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Measurement of copolar attenuation through the bright band at 4 & 7 GHz 1982

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MEASUREMENT OF COPOLAR ATTENUATION THROUGH THE BRIGHT BAND AT 4 & 7 GHz by JACK A. VAN DER STAR BASc, The University of British Columbia, 1977 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF APPLIED SCIENCE in THE DEPARTMENT OF ELECTRICAL ENGINEERING We accept this thesis as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA April 1982 • Jack A. Van der Star, 1982 I n p r e s e n t i n g t h i s t h e s i s i n p a r t i a l f u l f i l m e n t o f t h e r e q u i r e m e n t s f o r an a d v a n c e d d e g r e e a t t h e U n i v e r s i t y o f B r i t i s h C o l u m b i a , I a g r e e t h a t t h e L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r r e f e r e n c e a n d s t u d y . I f u r t h e r a g r e e t h a t p e r m i s s i o n f o r e x t e n s i v e c o p y i n g o f t h i s t h e s i s f o r s c h o l a r l y p u r p o s e s may be g r a n t e d by t h e h e a d o f my d e p a r t m e n t o r by h i s o r h e r r e p r e s e n t a t i v e s . I t i s u n d e r s t o o d t h a t c o p y i n g o r p u b l i c a t i o n o f t h i s t h e s i s f o r f i n a n c i a l g a i n s h a l l n o t be a l l o w e d w i t h o u t my w r i t t e n p e r m i s s i o n . D e p a r t m e n t o f The U n i v e r s i t y o f B r i t i s h C o l u m b i a 1956 Main Mall V a n c o u v e r , Canada V6T 1Y3 D a t e DE-6 (.3/81) ABSTRACT This thesis describes an experiment designed to measure microwave propa- gation through the bright band at 4 and 7 GHz. The path i s located approxi- mately 100 kilometers east of Vancouver, B r i t i s h Columbia, Canada, forming part of the Trans Canada Telephone System microwave network. The path i s coastal and mountainous i n nature, 41.3 kilometers i n length and experiences an average annual r a i n f a l l of 1600 mm/year. Due to these factors and an e l e - vation d i f f e r e n t i a l of 1227 m between transmitting and receiving s i t e s , the 0°C isotherm and hence bright band e f f e c t normally exist along the path from November to A p r i l . A measurement system based on remote telemetry i s used to obtain high resolution and accurately time-correlated data. Received signal l e v e l s are taken from f i v e selected 4 and 7 GHz microwave channels which are sampled at a rate of 10 Hz. Meteorological information i s obtained from f i v e locations along the path and sampled at a rate of 1 Hz. The data thus c o l l e c t e d are then time-correlated as i t arrives at the University of B r i t i s h Columbia (Vancouver) recording s i t e where i t i s analyzed using high-level language routines developed as part of a propagation data base management system. A detailed d e s c r i p t i o n of both the measurement system and the data management system are provided i n the t h e s i s . Results from several p r e c i p i t a t i o n systems indicate that bright band a t t e n u a t i o n can be many times ( i n dB per kilometer) greater than attenuation due to equivalent amounts of r a i n . This i s described by an Excess Attenuation ( i i ) Ratio (EAR) defined as the r a t i o of the excess attenuation i n dB/km c a l c u l a t e d using the Laws and Parson d i s t r i b u t i o n at 0°C. The experimental r e s u l t s com- pare favourably with those predicted by the t h e o r e t i c a l model of Matsumoto and N i s h i t s u j i . A s c i n t i l l a t i o n type fading phenomenon superimposed on the broad-band fade has also been observed during bright band propagation conditions. From the preliminary r e s u l t s t h i s phenomenon appears to be correlated with sudden changes i n d i f f e r e n t i a l temperature between transmitter and receiver s i t e s and thus a corresponding change i n the thickness of the bright band. ( i i±) TABLE OF CONTENTS Page ABSTRACT i i TABLE OF CONTENTS i v LIST OF ILLUSTRATIONS v i i LIST OF TABLES xiv ACKNOWLEDGEMENTS x v I. INTRODUCTION 1 1.1 The Importance of Microwave Propagation i n the Design of Microwave Systems 1 1.2 Factors A f f e c t i n g Microwave Propagation 2 1.2.1 Path Factors 3 1.2.2 Rain Attenuation 5 1.2.3 Multipath Fading 10 1.2.4 Other Propagation Factors 12 1.3 Improving R e l i a b i l i t y i n Path Design 13 1.4 Bright Band Effects 15 1.5 Scope of Thesis 21 1.5.1 The Research Program 21 1.5.2 Thesis Objectives 23 1.5.3 Thesis Outline 24 I I . THE EXPERIMENT 26 2.1 Introduction 26 2.2 The Path 26 2.3 Received Signal Monitoring 26 I I I . METEOROLOGICAL INSTRUMENTATION 35 3.1 System Design 35 3.1.1 Measurement C r i t e r i a 35 3.1.2 Site Selection 35 3.2 Meteorological Measurements 39 3.2.1 Rain 39 3.2.2 Temperature Transducer 41 3.2.3 Wind Velocity and Wind Direction Transducer . . . . 42 3.3. Meteorological-Data Sampling 42 (iv) Page IV. DATA ACQUISITION SYSTEM 45 4.1 Design C r i t e r i a for a Real Time Data A c q u i s i t i o n System . . 45 4.2 Site Selection 47 4.2.1 Received Signal Site 47 4.2.2 Meteorological Sites 48 4.3 Data C o l l e c t i o n Network Design 49 4.3.1 Data S t a t i s t i c s 49 4.3.2 Link Capacities 49 4.3.3 Node Considerations 50 4.3.4 Implementation of the Network Topology 51 4.4 Real Time Data Storage 52 4.4.1 Microprocessor Considerations . . 52 4.4.2 Data Storage Formats ,_2 4.5 Allowance for Future Data Requirements 4.6 An Alternate Data A c q u i s i t i o n System Using Chart Recorders. V. DATA BASE MANAGEMENT SYSTEM 5 5 5.1 Specifications 5.2 Design Considerations for DBMS Relative to Exi s t i n g and Future Systems 5 7 5.3 A System Description of DBMS 59 5.3.1 Data Transfer and Handling 59̂ 5.3.2 Estimate of DBMS Data Volumes 61 VI. RESULTS 62 6.1 Some I n i t i a l Results Obtained Using Chart Recording . . . . 62 6.2 Events Measured Using Remote Telemetry Showing Bright Band Propagation 66 6.2.1 January 23, 1982, 7:30-11:30 p.m 66 6.2.2 January 23, 1982, 2:00-4:30 p.m 70 6.2.3 February 19, 1982, 7:30-9:00 a.m 79 VII. CONCLUSIONS AND DIRECTIONS FOR FUTURE RESEARCH 84 7.1 Conclusions . . . 84 7.2 Directions f or Future Research 85 (v) Page 89 APPENDIX A Automatic Gain Control (AGC) Cali b r a t i o n s APPENDIX B Details of the Data A c q u i s i t i o n System Layout 9 5 APPENDIX C Equipment and Site Layouts 106 APPENDIX D Meteorological Transducers 122 APPENDIX E Signal Conditoning Units 127 APPENDIX F Analog to D i g i t a l Convertor 1 3 6 APPENDIX G D i g i t a l to Analog Convertor 142 APPENDIX H Modem Units 145 APPENDIX I Microprocessor Units 150 APPENDIX J Microprocessor Software 169 APPENDIX K The Bright Band Propagation Experiment's Data Base Management System . 190 REFERENCES 200 (vi) LIST OF ILLUSTRATIONS Figure Page 1.0 Path Factors 3 1.1 S p e c i f i c attenuation as a function of frequency for coherent wave propagation through uniform r a i n . The curves are based on the Laws and Parsons dropsize d i s t r i b u t i o n and the t e r - minal v e l o c i t i e s of Gunn and Kinzer. Rain tempera- ture of 20°C. Rain temperature of 0°C 3 1.2 A microwave system diagram i l l u s t r a t i n g space d i v e r s i t y , equipment d i v e r s i t y and frequency d i v e r s i t y 14 1.3 The character and c l a s s i f i c a t i o n of snow as i t passes through the bright band as seen on water-blue paper 18 1.4 F a l l i n g v e l o c i t y vs. r a d i i of raindrops and snowflakes . . . 19 1.5 Relative bright band geometries between slant path t e r r e s t i a l and earth space l i n k s 22 2.0 Geographical layout of the bright band propagation experiment 27 2.1 Path p r o f i l e : Ryder Lake to Dog Mountain 28 2.2 Path photographs 29 2.3 Frequency s e l e c t i o n plan and receiver equipment used at receiver s i t e 31 2.4 4 GHz receiver microwave transmission block diagram 32 2.5 7 GHz microwave transmission system block diagram 33 3.0 Measurement system layout 36 3.1 Path cross-section showing r e l a t i v e locations of the weather st a t i o n s i t e s 38 3.2 Weather s t a t i o n i n t e r - s i t e distances 40 3.3 Photograph of the U.B.C. Weatherlog microprocessor and meteorological signal conditioning unit 43 (vii) Figure Page 4.0 The data a c q u i s i t i o n system block diagram with component areas i d e n t i f i e d 46 4.1 Data c o l l e c t i o n network topology 51 4.2 Photograph of the Video Terminal Displaying Incoming Data . . 53 5.0 The bright band experiment data system flow chart 56 5.1 DBMS i n r e l a t i o n to other propagation data management systems 58 5.2 User flowchart to process time series data on the DBMS software system 60 6.0 Recordings of received s i g n a l at 7 GHz during bright band propagation: a) Event "A" (January 11-12, 1980) b) Event "B" (February 2, 1980) 63 6.1 The Agassiz temperature and 7.142 GHz signal l e v e l versus time 67 6.2 Agassiz r a i n rate and the 7.496 GHz signal l e v e l versus time 68 6.3 The 3.550 and 7.496 GHz sig n a l l e v e l s versus time 71 6.4 The Dog Mountain transmitter s i t e temperature and the 7.496 GHz reveiver l e v e l s versus time . . . . . . . 72 6.5 The Ryder Lake receiver s i t e temperature and the 7.496 GHz receiver l e v e l versus time 73 6.6 An expanded view at approximately 80 minutes into the event showing the Ryder Lake temperature and 7.496 GHz receiver l e v e l versus time 74 6.7 Ryder Lake d i f f e r e n t i a l temperature and 7.496 GHz received signal l e v e l versus time showing the fade di s c o n t i n u i t y 80 minutes into the event . . . . 75 6.8 Ryder Lake d i f f e r e n t i a l temperature and 7.496 GHz received s i g n a l l e v e l versus time showing d i s c o n t i n u i t i e s 30 minutes into the event 76 ( v i i i ) Figure Page 6.9 Ryder Lake windspeed, temperature and the 3.550 GHz received signal l e v e l versus time 77 6.10 An expanded view of the Ryder windspeed and 3.550 GHz received signal l e v e l versus time approximately 90 minutes in t o the event 78 6.11 Ryder Lake and Dog Mountain Temperature, Ryder Lake Windspeed and the 7.496 GHz receive signal l e v e l versus time 80 6.12 Agassiz r a i n rate and the 7.496 and 4.010 GHz receive signals versus time 81 6.13 Ryder Lake d i f f e r e n t i a l temperature and the 7.496 GH receive signal l e v e l versus time 83 7.0 Proposed system configuration to incorporate the d i g i t a l radio monitoring system 88 A-1 3550 MHz receiver AGC c a l i b r a t i o n 90 A-2 3790 MHz " " " 91 A -3 4010 MHz " " " 92 A-4 7142 MHz " " " 93 A-5 7496.5 MHz receiver AGC c a l i b r a t i o n . 94 B-l Path system layout for U.B.C. microwave propagation experiment . 97 B-2 Path p r o f i l e Ruby Creek to Ryder Lake 98 B-3 Path p r o f i l e : Bear Mountain to Ryder Lake 98 B-4 C i r c u i t layout from Dog Mountain to Ryder Lake 99 B-5 C i r c u i t layout from the Agassiz Experimental Farm to Ryder 99 Lake B-6 Schematic f o r the Ryder Lake to U.B.C. data c i r c u i t 10° B-7 The RS232 int e r f a c e f o r the Ryder Lake to U.B.C. data c i r c u i t 101 (ix) Figure Page C-l Ryder Lake s i t e photograph 102 C-2 Ryder Lake s i t e equipment configuration 103 C-3 Ryder Lake s i t e layout 104 C-4a Dog Mountain s i t e photograph 105 C-4b A photograph showing damage to the anemometer caused by severe i c i n g conditions at Dog Mountain 106 C-5 Dog Mountain s i t e equipment configuration 107 C-6 Dog Mountain s i t e layout 108 C-7 Agassiz Experimental Farm s i t e photograph 109 C-8 Agassiz Experimental Farm s i t e equipment configuration . . . 110 C-9 Agassiz Experimental Farm s i t e layout I l l C-10 Ruby Creek s i t e photograph 112 C - l l Ruby Creek s i t e equipment configuration 113 C-12 Ruby Creek s i t e layout 114 C-13 Bear Mountain s i t e photograph 115 C-14 Bear Mountain s i t e equipment configuration 117 C-15 Bear Mountain s i t e layout 118 C-16 The University of B r i t i s h Columbia s i t e photograph 119 C-17 The University of B r i t i s h Columbia equipment configuration . 120 C-18 The University of B r i t i s h Columbia s i t e layout 121 D-l A photograph of the anemometer 122 D-2 Anemometer c i r c u i t and wiring diagram 123 D-3 A t y p i c a l r a i n bucket and tip p i n g assembly 124 D-4 Photograph of the temperature probe 125 (x) Figure Page E-1 Top view Photograph of the meteorological s i g n a l conditioning unit 127 E-2 C i r c u i t schematic f o r the meteorological s i g n a l conditioning unit 128 E-3 Front and rear views of the meteorological s i g n a l 129 E-4 C i r c u i t schematic for the Bear Mountain s i g n a l conditioning card 132 E-5 C i r c u i t schematic for the receiver s i g n a l conditioning card . 134 F- l Photographs showing the A/D convertor separately and i n s t a l l e d 137 F-2 C i r c u i t schematic and physical layout for the Weatherlog analog to d i g i t a l convertor 139 F-3 Control s i g n a l timing diagram for the A/D convertor 140 F-4 Sample oscilloscope traces of the A/D output during c a l i b r a t i o n 140 F-5 A/D c a l i b r a t i o n program 141 G-l C i r c u i t schematic for the D/A convertor 143 G-2 L i s t i n g of the program to provide chart recordings from the receiver data using the D/A converter 144 H-l Photograph of an i n s t a l l e d modem transmit unit 145 H-2 Interface schematic for a Weatherlog modem transmit unit . . 147 H-3 Physical drawing of the Ryder Lake receiver unit showing top, front and rear views 148 H-4 Interface schematic for one of the modem receiver units . . . 149 1-1 Physical drawing of the UBC data formatting ( P//1) micro- processor showing fr o n t , top and rear views 151 1-2 Physical drawing of the UBC data processing ( P#2) micro- processor showing front, top and rear views 152 (xi) Figure Page 1-3 Photograph showing the i n t e r i o r layout of the data formatting (uP#l) and data processing (uP#2) microprocessors 153 1-4 .. C i r c u i t schematic and physical layout of the asynchronous interface (ACIA) card 156 1-5 Physical drawing of the Ryder Lake microprocessor unit showing front, top and rear views 160 1-6 Physical drawing of the Weatherlog microprocessor showing front, top and rear views 162 1-7 Photograph showing the i n t e r i o r layout of a t y p i c a l UBC Weatherlog microprocessor unit 163 1-8 Physical drawing of the low power microprocessor unit used at Bear Mountain 165 1-9 Photograph showing the i n t e r i o r layout of the Bear Mountain microprocessor unit 166 1-10 Equipment configuration to transfer data from the cassette tape drive to the NOVA 840 magnetic tape drive 167 1-11 C i r c u i t diagram of the RS232C to current loop interface . . . 168 J - l a Program flow chart for uP#l; the UBC data formatter . . . . 171 J-lb Data formatter buffer memory organization 172 J-2 Program flow charts for uP//2; the UBC data processor micro- processor unit 173 J-3 Diagram showing the structure of the time series queue (TSQ) 176 J-4 Data a c q u i s i t i o n flow chart for the Ryder Lake datalog 6800 microprocessor 183 J-5 Program flow chart for the UBC Weatherlog 8085 data a c q u i s i - t i o n microprocessors 185 J-6 Data a c q u i s i t i o n and control program flow chart for the remote Bear Mountain 1802 microprocessor unit 187 J-7 Program flow chart to transfer data from cassette tapes to magnetic tape using the NOVA 840 189 ( x i i ) gure Page K-1 DBMS functional flow chart showing completion status . . . . 192 K-2 DBMS main program flow chart 193 K-3 Sample P l o t t i n g Run 199 ( x i i i ) LIST OF TABLES Table Page 1 . 0 Attenuation M u l t i p l i e r s Due to Watery Snow 2 0 2 . 0 Microwave Transmission Calculations . 3 4 3 . 0 Geographical and Functional Site Details 37 3.1 Inter-Site Distances as a Function of Path Length 4 0 4 . 0 Data A c q u i s i t i o n System Link Capacities 5 4 5 . 0 DBMS Data Volume Estimates 6 1 6 . 0 Preliminary Results 6 4 6.1 Bright Band Excess Attenuation Ratio (EAR) Results 6 4 6.2 January 23, 1982 Results (7 GHz) 6 9 6.3 Bright-Band Excess Attenuation (EAR) Results 6 9 6.4 February 19, 1982 Results 8 2 6 . 5 February 19, 1982 EAR Results 8 2 A-1 Receiver Frequencies Polarizations and Associated AGC Curves. 8 9 B-l VHF Radio Path Transmission Calculations 9 6 U E-1 The Resistor Values Used i n the D i f f e r e n t i a l Gain Block f o r Optimum Gain 1 3 3 F - l A/D Convertor Channel Assignment Table 1 3 8 H-l Modem Center Frequency Assignments 1 4 6 1-1 I/O Port Address assignments f o r the Data Formatter Unit uP#l 1 5 4 1-2 I/O Port Address assignments for the Data Processor Unit uP#2 1 5 5 1-3 6800 Interrupt Vectors 1 5 7 1-4 Analog to D i g i t a l (A/D) Convertor Channel Assignments . . . . -j.59 1-5 1/0 Port Address Assignments f o r the Ryder Lake Unit . . . . 1 6 1 J - l RAM Time Assignments (uP#l) 1 7 8 J-2 Time Series Block Format 1 7 9 J-3 Data Format f o r the D i s t r i b u t i o n Buffer I 8 0 K-1 Data Directory for the Time Series Format 1 9 5 (xiv) ACKNOWLEDGEMENTS I would l i k e to acknowledge my appreciation to Dr. M.M.Z. Kharadly who has provided me with much needed support, supervision and suggestions throughout the course of t h i s research. A g r a t e f u l acknowledgement i s also extended to Mr. Nev i l l e Owen of the B r i t i s h Columbia Telephone Company for his much appreciated assistance, his f i e l d coordination and his advice throughout my thesis work. I would also l i k e to thank the following people at the B r i t i s h Columbia Telephone Company for t h e i r invaluable contributions made during this research: Mr. B i l l Squans Mr. Stan Dahl Mr. Red Matthews Mr. George Gatt Mr. Dwight Chan Mr. Peter Claydon In the same way I would l i k e to thank the following s t a f f at the Communications Research Centre i n Ottawa for the i r numerous suggestions, for th e i r continued support and for providing a stimulating working environment during my stay: Dr. Stewart McCormick Dr. Rod Olsen Dr. Dick Butler Dr. Ben Segal Dr. John Strickland Mr. N e v i l l e Reed Mr. Hassen Kheirallah Mr. Joe Schlesak (xv) My gratitude i s also extended to the following people at the Agassiz Experimental Farm for generously providing valuable back up meteorological data from t h e i r weather s t a t i o n , for maintaining the UBC chart recordings and looking a f t e r the UBC Weatherlog computer: Mr. Frank DeZwaan Ms. Moira Jewell I would l i k e to give many thanks to Dr. T e r r y Enegren and Mr. David Michelson, for implementing the integration phase of the remote telemetry and DBMS systems , making the results possible. I would also l i k e to express my gratitude to the following s t a f f at the Department of E l e c t r i c a l Engineering f o r t h e i r contributions: Mr. James Johnston Mr. E r i c Minch Mr. Edwin Lee Mr. Jun Lee Thanks are due to Ms. Sherry Lashmar and Mrs. Kathy Brindamour for typing the manuscript, Mr. Ben Van der Star for his help i n assembling the e l e c - tronics and to Mr. Len Smart for the development of the entry procedure and p l o t t i n g routine packages. I would also l i k e to thank a l l my friends and colleagues, p a r t i c u l a r l y Dr. B a s i l P e t e r s , Mr. Peter van der Gracht, Mr. Konrad Mauch and Mr. Frank Peabody for creating an enjoyable and stimulating working environ- ment. I would l i k e to g r e a t f u l l y acknowledge, as w e l l , the Agassiz Experi- mental Farm and the Canadian Broadcasting Corporation for t h e i r cooperation i n allowing the use of t h e i r f a c i l i t i e s at intermediate v a l l e y s i t e s along the path. (xvi) This work was supported by the B r i t i s h Columbia Telephone Company through contract number 0007Q8 (NO/KO), the Communications Research Centre i n Ottawa through contract numbers OSU 79-00061, OSU 80-00146 and 81-00112 and The National Science and Engineering Research Council of Canada through grant number A-3344. F i n a l l y , I would l i k e to thank my wife Kathy for her continued patience, encouragement and support during my master's program. ( x v i i ) 1 CHAPTER 1 INTRODUCTION 1.1 The Importance of Microwave Propagation In the Design of Microwave Systems Microwave propagation parameters af f e c t the r e l i a b i l i t y ( a v a i l a b i l i t y ) of t e r r e s t r i a l and s a t e l l i t e communication systems and thus have a major i n - fluence on t h e i r economics [1]. Therefore, techniques to confidently estimate t h i s r e l i a b i l i t y are es s e n t i a l before system planners and designers can imple- ment cost e f f e c t i v e and economically viable microwave transmission systems [2]. Microwave transmission systems below 10 GHz include both s a t e l l i t e and t e r r e s t r i a l networks with common c a r r i e r s and CATV operators being the main users. The least demanding from an a v a i l a b i l i t y viewpoint i s the CATV opera- tor. His performance requirements are deemed s a t i s f a c t o r y i f the system i s available for more than 99.8% of the time, which represents an outage of approximately 1000 minutes per year [3]. On the other hand, the most demand- ing user of communication systems are the common c a r r i e r s who presently operate at 4, 6 and 7 GHz and propose to st a r t operations i n the 8 GHz band [4]. An example of a t y p i c a l common c a r r i e r system s p e c i f i c a t i o n i s the one proposed for the Vancouver to Halifax, 8 GHz d i g i t a l c i r c u i t . The system i s sp e c i f i e d to be available for more than 99.98% of the time [5], where the u n a v a i l a b i l i t y of less than 0.02% has been allocated with an allowance of 1/2 (.01%) for equipment f a i l u r e s , 1/4 (.005%) for r a i n outages and 1/4 (.005%) for multi-path fading outage. On an average per-hop basis this represents an 2 u n a v a i l a b i l i t y requirement of less than .0002% (63.2 seconds) of the time, where the combined propagation outage factors of r a i n and fading may not account for more than .0001% (31.6 seconds). Therefore, accurate estimation of the propagation r e l i a b i l i t y i s e s s e n t i a l before i n s t a l l a t i o n since propagation factors not accounted for i n the o r i g i n a l design could prevent meeting the t o t a l system a v a i l a b i l i t y " objective. In t h i s l i g h t , the work described by this thesis was started to study factors associated with b r i g h t - band propagation at 4 and 7 GHz, for which no account has yet been made. 1.2 Factors A f f e c t i n g Microwave Propagation Microwave propagation for frequencies below 10 GHz are l a r g e l y affected by a path's geometry and associated weather c h a r a c t e r i s t i c s . Microwave propa- gation i s affected by the path's geometry i n the way of free space attenua- t i o n , curvature changes due to variations i n the r e f r a c t i v i t y p r o f i l e and obstruction losses. Propagation factors related to meteorological conditions along a microwave path result i n r a i n attenuation, multlpath fading, and reductions i n received signal l e v e l s due to the presence of the bright-band. Other factors such as gaseous absorption by water vapour oxygen and fog also exist to a minor extent below 10.GHz. A discussion of these factors and t h e i r determination i s the subject of this next section. 3 1.2.1 Path Factors Figure 1.0 shows an example of a l i n e - o f - s i g h t microwave path which would form a segment i n a common-carrier's back-bone microwave system. It would t y p i c a l l y have a hop length of 40 to 60 km, a fade margin of 40 dB and an operating frequency between 4 and 10 GHz [5]. Figure 1.0 Path Factors 4 The E f f e c t Due to Changes In R e f r a c t i v i t y Although a microwave path i s often termed to be " l i n e - o f - s i g h t " , the beam does not t r a v e l i n a straight l i n e through the atmosphere from the transmitter to the receiver but rather bends as a res u l t of a s l i g h t decrease i n the atmospheric r e f r a c t i v e index with height. This bending i s described by a "K" or equivalent earth radius factor which, i f mul t i p l i e d by the actual earth radius r Q , gives the f i c t i c i o u s earth curve, r, t r a v e l l e d by the propagating microwave beam. Therefore, variations i n atmospheric r e f r a c t i v i t y cause cor- responding changes i n the K factor and are described as a function of atmos- pheric temperature and water vapour content, as follows [6]: N = (n-1) 10 6 = 77.6 | + 3 , 7 3 1 0 5 6 (1-1) T 2 dry term wet term where N: r e f r a c t i v i t y (N units) n: r e f r a c t i v e index P: atmospheric pressure (m bar) T: absolute temperature (°K) e: water vapour pressure (m bar) If a point i s taken at a fixed elevation the radius of curvature of the beam, r, r e l a t i v e to the earth's radius r Q can be expressed as a function of the v e r t i c a l index of r e f r a c t i o n gradient dn/dh to give the following expres- sion f o r the K factor [7]: K - (1 + r | M 1 = (1 / 157) 1 r v o dh' v dh 1 o , (1-2) r = 6370 km o Published maps on world atmospheric radio r e f r a c t i v i t y and r e f r a c t i v i t y 5 gradients are available [8,9,10]. Calculation of the Free Space Attenuation The attenuation to a microwave signal emitted from an i s o t r o p i c radiator can be determined as a function of frequency and distance by the following expression, [2] : AdB = 9 2 , 4 + 2 0 1 O g 1 0 f + 2 0 l Q g i o D ( 1 _ 3 ) where, A : free space attenuation (dB) OLD f: frequency (GHz) D: distance (km) Obstruction Losses Obstruction losses vary according to a path's c h a r a c t e r i s t i c p r o f i l e and operating frequency which allows t h e i r estimation, eg. Bullington [11]. 1.2.2 Rain Attenuation Early t h e o r e t i c a l estimates of r a i n attenuation on microwave propagation were made by Ryde and Ryde [12,13] during World War H and were based on a f i r s t - o r d e r forward-scattering model that used a uniform d i s t r i b u t i o n of equi- diameter spheres. The r e s u l t i n g expression for attenuation for a plane wave i s given i n equation (1-4): a = 0.4343 x N x T r x D 2 x f (D / A , m) dB/km (1- 4) Si where, a: attenuation (dB/Km) N: density (m - 3) D: drop diameter (mm) 6 m: . n-jnx, the complex r e f r a c t i v e index of water f f l : r a t i o of energy absorbed and scattered to that i n c i d e n t upon the p r o j e c t e d a r e a of the d r o p . Medhurst, i n his review [14], corrected the numerical c a l c u l a t i o n s derived by Ryde using t h i s model but found a large v a r i a t i o n , greater than expected, i n experimental measurements [15,16,17,18]. Medhurst suggested that some of this v a r i a t i o n could be attributed to multiple scattering processes but further t h e o r e t i c a l analysis by Crane [19] and Rogers & Olsen [20] deter- mined that this e f f e c t would be i n s i g n i f i c a n t and the "single s c a t t e r i n g " model for rai n attenuation was, i n f a c t , v a l i d for frequencies lower than 20 GHz. The discrepancy between theory and experiment which Medhurst observed has since been attributed to inaccurate r a i n rate measurements. Most researchers at present acknowledge that good agreement between t h e o r e t i c a l estimates and c a r e f u l l y obtained experimental observations are possible [21]. In order to allow the c a l c u l a t i o n of the attenuation c o e f f i c i e n t using path-average ra i n rate data, a r e l a t i o n between the rai n rate, the density and the drop diameter i s required. This i s given i n terms of the terminal v e l o c i t y of a f a l l i n g drop i n (1-5): R = 1.885 x v x N x D 3 (mm/hr) (1-5) where, R: r a i n rate (mm/hr) v: terminal v e l o c i t y (m/sec) N: density (m - 3) D: drop diameter (mm) The terminal v e l o c i t y i s related to the drop diameter, as measured by Gunn and Kinzer [14] , and therefore the c a l c u l a t i o n of the attenuation c o e f f i c i e n t i s 7 possible for uniform r a i n for a single drop size using (1-4). P h y s i c a l l y , r a i n i s composed of drop-sizes e x h i b i t i n g a continuous range of diameters from 0.5 mm to 7 mm. Integrating the s p e c i f i c attenuation r e l a t i o n for a single drop size (1-4) over the whole drop size d i s t r i b u t i o n for various r a i n rates gives the attenuation by actual r a i n vs. r a i n rate. Figure 1.1, taken from [22], provides a graph of the s p e c i f i c attenuation versus frequency at various r a i n rates using this approach. The a p p l i c a b i l i t y of the r e s u l t s derived using the Ryde model i s dependent on the diameter of the spheres used and, therefore, the proper s e l e c t i o n of the drop size d i s t r i b u t i o n i s important. For most temperate- continental r a i n f a l l types the Laws and Parson d i s t r i b u t i o n provides a good c o r r e l a t i o n between the Ryde model and experiment [23]. Other drop size d i s - t r i b u t i o n s are available for d i f f e r i n g applications which include the Marshall and Palmer d i s t r i b u t i o n [24] and the Joss et a l . d i s t r i b u t i o n s [25] for d r i z z l e , wide spread r a i n and thunderstorms. A Simplified Empirical Model for Rain Attenuation as a Function of Rain Rate Further improvements to the c a l c u l a t i o n of s p e c i f i c attenuation as a function of r a i n rate have been made by Olsen, Rodgers and Hodge [22], who have developed the s i m p l i f y i n g empirical formula i n (1-6), known as the A - R r e l a t i o n : A = (1-6) where, A: attenuation (dB/Km) 8 F R E Q U E N C Y (GHz) Figure 1.1 S p e c i f i c attenuation as a function of frequency for coherent wave propagation through uniform r a i n . The curves are based on Laws and Parsons dropsize d i s t r i b u t i o n and the terminal v e l o c i t i e s of Gunn and Kinzer. Rain temperature of 20°C. Rain temperature of 0°C. 9 R: r a i n rate (mm/hr) a,b: frequency and r a i n temperature dependent parameters tabulated i n [26] Rain Rate Measurement The determination of path attenuation due to r a i n f a l l requires the accur- ate measurement of path average ra i n rate. This i s complicated by the fact that r a i n i s non-uniform i n nature and often consists of rain c e l l s of l i m i t e d extent [21]. Therefore, to obtain an accurate path average ra i n rate, the i n d i v i d u a l r a i n rates must be sampled at as many locations along the path as possible [26,27] or be estimated using synthetic storm techniques [59-62]. In a d i s t r i b u t e d system of rain guages, the path can be treated i n seg- ments where the t o t a l path attenuation due to rai n i s the sum of the i n d i v i d u a l segment attenuations, as follows: n n A = I A i = I  a x ( R ± n ±  ( 1 " 7 ) i = l i = l where, R^: rai n rate at guage i (mm/hr) Aj_: length of segment i as a percentage of path length (R^): s p e c i f i c attenuation i n dB/km at rain rate R̂ An approximation to (1-7) i s usually adopted, (1-8), which uses the path average r a i n rate d i r e c t l y through the assumption that variations i n r a i n rate segments are s u f f i c i e n t l y small that the inter-segment s p e c i f i c attenuations are l i n e a r l y r e l a t e d . 10 n ^ x £ A = a x { I 1 L *) x L (1-8) J * where, A: t o t a l path attenuation a^: s p e c i f i c attenuation for a determined path average r a i n rate (dB/km) R^: rai n rate for segment i (mm/hr) £^: length of segment i L: t o t a l path length (km) *: path average r a i n rate 1.2.3 Multipath Fading Under normal atmospheric conditions a l i n e - o f - s i g h t hop provides one propagation path between transmitter and receiver antennas. If cer t a i n changes i n the r e f r a c t i v i t y p r o f i l e occur, add i t i o n a l propagation paths can result p a r a l l e l to the main beam [6,28]. When these arr i v e together at the receiver, they add together according to t h e i r phase r e l a t i o n s h i p producing vari a t i o n s i n the received signal known as multipath fading. For N multiple p r o p a g a t i o n paths of amplitude and delay the transfer function describ- ing t h i s phenomenon can be expressed as follows [6]: N - j irf T H(f) = I a e n (1-9) , n n=l 0 11 Measurement Techniques and P h y s i c a l Models Invest igat ions of mult ipath have e i ther used a time-domain radar t e c h - nique where the a r r i v a l of pulses are monitored by number, amplitude and time delay or used a frequency-domain technique where the path i s swept i n f r e - quency and Four ier transformations are used to obtain the time-domain responses [29,30,31,32]. The conclus ion from these experiments was that the number of propagation paths depends s t rongly on the l i n k s ' meteorologica l condi t ions and that the frequency of a mult ipath fade increases with fade depth. Sanberg, using r e s u l t s from frequency swept measurements concluded that no mult ipath events occurred which could not be character ized by four or fewer rays [33]. Other swept measurements conducted by Martin [34] concluded that fades of the order of 20 dB are p r imar i l y due to two path propagation while deeper fades , of the order of 40 dB or more are due to the existence of at least three paths. Models based on these phys ica l parameters have been v e r i f i e d e x p e r i - mental ly for duct ing and for s p e c i a l i z e d types of atmospheric l ayer ing [35] but a general model which can be appl ied e m p i r i c a l l y from d i r e c t l y measured mult ipath parameters has yet to be developed [6]. r Est imat ion of Mul t ipath Propagation Outages In order to character ize mult ipath propagation i n a manner which allows path a v a i l a b i l i t i e s to be est imated, a general formula has been developed by Barnett [36] to c a l c u l a t e mult ipath outage p r o b a b i l i t i e s as f o l l o w s : U = a x b x 6.0 x 10~ 7 x f x D 3 x 1 0 t _ F / 1 0 ] (1-10) 12 where, U: fade p r o b a b i l i t y below fade margin a: path roughness factor (4 for very smooth, 1 for average with some roughness and 1/4 for very rough mountainous t e r r a i n . ) b: factor to convert worst month p r o b a b i l i t y to annual p r o b a b i l i t y (1/2 for hot humid, 1/4 for average inland and 1/8 for very dry mountainous) f: frequency (GHz) D: path length (km) F: fade margin under normal operation A v a i l a b i l i t y For propagation factors such as multipath the a v a i l a b i l i t y i s given by (1-11) [2]. A = (1-U) x 100% (1-11) where: A - A v a i l a b i l i t y defined as the percentage of time the received signal i s useable U - fade p r o b a b i l i t y defined as the f r a c t i o n of time the received signa l i s not useable. 1.2.4 Other Propagation Factors Gaseous Absorption by Water Vapour, Oxygen and Fog A minor e f f e c t on radio wave propagation near the earth's surface for frequencies lower than 10 GHz i s due to the absorption by water vapour and oxygen. This e f f e c t increases with higher frequencies. At 10 GHz the attenu- ation i s .007 dB/km at 20°C for oxygen absorption and .0045 dB/km at 20°C 13 for water vapour absorption [10]. The attenuation, therefore, amounts to less than one dB for an average 50 km microwave path. Fog also attenuates micro- waves by the same scattering mechanism as r a i n but due to the much smaller drop diameters involved the amount of attenuation i s minimal. Measured attenuations of 1 dB/km at 90 GHz are reported [37] which means for an average l i n k the attenuation i s considerably less than one dB for frequencies lower than 10 GHz. Bright Band E f f e c t s There i s increasing evidence to suggest that the bright band causes attenuation i n excess of what i s normally predicted by a rai n model. This i s discussed i n d e t a i l i n section 1.4. 1.3 Improving R e l i a b i l i t y i n Path Design Path r e l i a b i l i t y ( a v a i l a b i l i t y ) i s a combined function of the propagation and equipment r e l i a b i l i t i e s and therefore both need to be considered i n the design of a microwave l i n k [2]. Improvements i n propagation r e l i a b i l i t y can be achieved through careful path s e l e c t i o n and the use of frequency and space d i v e r s i t y to minimize the ef f e c t s of multipath and r a i n attenuation, while improvements i n equipment a v a i l a b i l i t y are accomplished by using r e l i a b l e system components and redundant configurations. Figure 1.2 i l l u s t r a t e s these techniques. . 14 Figure 1.2 A Microwave System Diagram I l l u s t r a t i n g Space D i v e r s i t y , Equipment Di v e r s i t y and Frequency Di v e r s i t y . For a t y p i c a l non-diversity path of given path distance, fade margin, frequency and r a i n s t a t i s t i c s the outage p r o b a b i l i t i e s due to r a i n and multi- path fading can be calculated from equations (1-6) and (1-10) res p e c t i v e l y . If further propagation r e l i a b i l i t y improvement i s required space d i v e r s i t y and/or frequency d i v e r s i t y can be used on the l i n k . The re l a t i o n s h i p used to calculate the space d i v e r s i t y improvement factor i s given by Vigants [38] as follows: I__ = (1.2 x 10~ 3 x f x S 2 x 1 0 [ F / 1 ° ] ) / D (1-12) where, T-SD: s P a c e d i v e r s i t y improvement factor 15 S: v e r t i c a l antenna spacing i n meters D: path length i n kilometers F: fade margin associated with the second antenna f: frequency i n GHz. Frequency D i v e r s i t y S i m i l a r l y , a r e l a t i o n to calculate the frequency d i v e r s i t y improvement factor i s given by Barnett . [36]: I F D = a x [Af/f] x 1 0 [ F / 1 0 ] (1-13) where, I F J J : frequency d i v e r s i t y improvement factor a: frequency band factor (3 for the 890 - 960 MHz band 1 for the 2 GHz band 1/2 for the 4 GHz band 1/4 for the 6 GHz band 1/8 for the 7 & 8 GHz bands and 1/12 for the 12 GHz band) f: frequency (Hz) Af: frequency spacing (Hz) F: fade margin (dB) 1.4 Bright Band E f f e c t s The bright band i s the t r a n s i t i o n region immediately below the 0°C i s o - therm where f a l l i n g snowflakes melt and are turning into r a i n . Thus, br i g h t - band propagation occurs when a microwave beam passes through p r e c i p i t a t i o n i n thi s region. It was named during World War II when high radar returns r e s u l t - ing from t h i s melting layer region caused a "bright band" on the radar screens. 1 6 From a propagation point of view, there i s increasing evidence which suggests that, during wet snow or sleet events, low angle microwave beams i n temperate marine climates experience attenuation i n excess of values predicted due to r a i n [39,40,41]. It has been postulated that the excess attenuation i s a result of increased absorption and s c a t t e r i n g upon transmission through the 0°C isotherm or bright band. Accurate d i r e c t measurement of this excess attenuation i s d i f f i c u l t and there have been only few reported cases where quantitative r e s u l t s are given. Oomeri and Aoyagi [40] from propagation tests carried out Sapporo and Hokuriku, Japan, indicate that s l e e t f a l l attenution (in dB) to be six to seven times as large as the attenuation that can be pre- dicted for the equivalent amount of r a i n . Watson [39], i n his survey, c i t e s propagation studies carried out i n the USSR [Al] which found s i m i l a r r e s u l t s . Measurements taken using radar also shows excessive attenuation i n the presence of bright band [42-47]. In addition to these published r e s u l t s , there are some reports i n Canada, Scandanavia and the United Kingdom of exces- sive attenuation i n the presence of sleet or wet snow [39]. Recently, by using s t a l l i t e beacon signals to measure di r e c t attenuation together with proven radar prediction methods for r a i n attenuation, more accurate measurements of bright band attenuation have been taken [44,47,48]. In t h i s technique the r a i n attenuation i s calculated to the base of the bright band and then this value i s subtracted from the t o t a l attenuation to give an amount a t t r i b u t a b l e to bright-band attenuation. Measurements taken by Hendry Antar, Schlesak and Olsen [47] using a dual-channel p o l a r i z a t i o n d i v e r s i t y radar show a c o r r e l a t i o n of increased excess attenuation ascribed to the melt- 17 ing layer with an increase i n the v e r t i c a l thickness of the bright band layer for a given p r e c i p i t a t i o n rate. They also found that the percentage of pre- ferred o r i e n t a t i o n of the p a r t i c l e s i n the melting layer to be t y p i c a l l y 20% as opposed to 65% to 85%, for r a i n . An attempt to model the bright band has been made i n a series of paper by N i s h i t s u j i and Matsumoto [49,50,51] using the Ryde and Ryde approach [12,13]. Their f i r s t paper [49] establishes a set of Nrs density d i s t r i b u t i o n tables of snowflake-size d i s t r i b u t i o n s for various c l a s s i f i c a t i o n s of snow si m i l a r to the tables of Laws and Parson. These d i s t r i b u t i o n tables were prepared for four snow c l a s s i f i c a t i o n s : namely, dry snow, moist snow, wet snow and watery snow of which the l a s t three represent snow types present i n the bright band. Figure 1.3 taken from this paper i l l u s t r a t e s these progressive changes i n the character of snowflakes as they would appear on water-blue paper for snow as i t passes through the bright band. In addition, N i s h i t s u j i and Matsumoto measured the f a l l i n g v e l o c i t y corresponding to each snowflake diameter and for each snow c l a s s i f i c a t i o n . A graph of these results i s presented i n Figure 1.4 taken from [49]. The p r e c i p i t a t i o n rate (P) can then be related to the density (Nrs), f a l l v e l o c i t y (Vrs) and the radius ( r r ) to allow the c a l c u l a t i o n of the snow attenuation f o r each snow c l a s s i f i c a t i o n as follows [51]: P = 4 7 T ^ r 3 V N (1-14) 3 r rs rs The greatest attenuation for equal p r e c i p i t a t i o n rates was then found to be due to watery snow i n the frequency range between 4 and 7 GHz. In terms of attenuation r e l a t i v e to r a i n of the same p r e c i p i t a t i o n rate the attenuation % • Large Small Rain drop or watery snow (2) • •- large Small Wotery snow (3) 0 Watery snow or wet snow (4) # Wet snow (5) wet snow or moist snow (6) Moist Snow (.7) Moist snow dry snow (B) Dry snow (9) • Graupel Figure 1.3 The Character and C l a s s i f i c a t i o n of Snow as i t passes through the Bright Band as seen on Water-Blue Paper. 10 0 .5 1.0 Radius ol ro in drop and snowfloke {cm) Figure 1.4 F a l l i n g Velocity vs. Radii of Raindrops and Snowflakes 20 due to watery snow i n this range was calculated to be 15 times i n dB's per kilometer. Table 1.0 presents these m u l t i p l i e r ' s i n dB's per kilometer for various frequencies as derived from the model f or wet snow [51]. There are several supporting physical reasons why the attenuation at a fixed p r e c i p i t a t i o n rate for watery and wet snow i s greater than that due to r a i n f a l l [50]: a) for a raindrop and watery snowflake of the same weight the l a t t e r has the greater radius; b) the rate of f a l l of watery snow as compared to a raindrop i s smaller so that the number of snowflakes i n a unit volume i s greater than that of r a i n ; c) snowflakes do not break up during t h e i r f a l l through the melting layer since the drop size spectrum j u s t above the melting layer i s s i m i l a r i n shape to that just below i t [53]; Table 1.0 Attenuation M u l t i p l i e r s Due to Watery Snow. Frequency (GHz) Attenuation M u l t i p l i e r (dB/km) 1 2 4 7 11 24 35 50 0.2 4.6 15.1 15.0 12.1 7.3 7.0 6.5 21 d) the d i s t r i b u t i o n of raindrop r a d i i i s semilogarithmic while that of watery snow i s the sum of the same semilogarithm due to aggregation at the top of the melting layer [52-57], which means there are many large sized snowflakes i n the bright band. This greatly impacts attenuation since the increase i s proportional to the cube of the diameter of a snowflake or raindrop. Possible Impact on Microwave Transmission Systems For paths such as earth-space l i n k s and slant paths i n temperate marine climates the bright band could have a s i g n i f i c a n t e f f e c t which suggests that allowances should be made for this type of attenuation when predicting propa- gation r e l i a b i l i t y . Excess attenuation as a result of propagation through the bright band appears to be increasingly more important to account f o r as frequencies greater than 8 GHz are used. Examples showing the geometries associated with an earth-space l i n k and a slant-path t e r r e s t i a l l i n k r e l a t i v e to the bright band are shown i n Figure 1.5 1.5 Scope of Thesis 1.5.1 The Research Program The objectives of the present propagation research program which i s being c a r r i e d out i n association with the Canadian Research Centre i n Ottawa and the B r i t i s h Columbia Telephone Company i n Vancouver are as follows: 1) To provide the f a c i l i t i e s to perform research into the various aspects of both analog and d i g i t a l microwave propagation. 2) To select and f u l l y instrument a suitable path(s) for the monitoring of a number of factors that a f f e c t microwave propagation. Figure 1.5 Relative Bright Geometries Between Slant Path T e r r e s t i a l and Earth-Space Links 23 3) To e s t a b l i s h the necessary data c o l l e c t i o n and data analysis i n f r a - structure to e f f i c i e n t l y store, r e t r i e v e and analyze large amounts of propagation data. 4) To e s t a b l i s h the r e l a t i o n s h i p , i f any, between the occurrence of bright band and multipath fading phenomenon and the performance of c e r t a i n microwave l i n k s . 5) To be able to determine a s t a t i s t i c a l model which takes into account bright band attenuation factors that would enable improved a v a i l a b i l i t y design for both t e r r e s t r i a l and earth space paths. 1.5.2 Thesis Objectives The main objectives of the work i n this thesis may be stated as follows: 1) I d e n t i f i c a t i o n and measurement of the parameters a f f e c t i n g bright band propagation. 2) Development and implementation of a working telemetry based data c o l - l e c t i o n system which can accurately measure, time correlate and pre- process large amounts of received signal and meteorological data. 3) Development of a data base management system to store and analyze the data c o l l e c t e d . 4) Analysis of the data c o l l e c t e d to determine bright-band propagation e f f e c t s i n the 4 and 7 GHZ range and provide a comparison to the t h e o r e t i c a l model 24 1.5.3 Thesis Outline A de s c r i p t i o n of the path selected i s the subject of Chapter I I . Included i s a path p r o f i l e , a summary of the path's previous propagation h i s t o r y as well as the calculated and measured system performance charac- t e r i s t i c s . Chapter III deals with the c r i t e r i a for meteorological s i t e s e l e c t i o n and includes a description of the wind d i r e c t i o n , wind speed, temperature and r a i n transducers through which the meteorological parameters a f f e c t i n g excess path attenuation can be measured. Chapter IV deals with the data handling aspects of c o l l e c t i n g the data from received signal and meteorological sensors and the network design for doing this i n real time. Included are sections dealing with the data s t a t i s - t i c s , the l i n k c a p a c i t i e s , the microprocessors and the preprocessed time series and d i s t r i b u t i o n series formats. Chapter V deals with the s p e c i f i c a t i o n , the design and the implementation of a data base management system. This i s discussed i n r e l a t i o n to software systems presently i n existence, to the current bright band system and to future propagation research software requirements. Included i s an i l l u s t r a - t i o n of the t o t a l data processing and handling system and the economics associated with using t h i s system. Chapter VI presents results of copolar attenuation through the bright band at 4 and 7 GHz. One set of these r e s u l t s has been taken from chart recordings during January-February 1980. Another set of results taken during January-February 1982 using the telemetry based data c o l l e c t i o n system as described i n Chapters I I I , IV, and V, are also presented i n th i s chapter. 25 These r e s u l t s represent a l i m i t e d set to convey the character of the data measured and the nature of bright band propagation and to i l l u s t r a t e possible correlations to meteorological parameters. Conclusions based on both the chart recorder and the telemetry based system are presented i n Chapter VII as well as suggestions to further develope the measurement system and the analysis techniques used i n this t h e s i s . 26 CHAPTER II THE EXPERIMENT 2.1 Introduction This chapter provides a description of the path selected, the equipment used and the system fade margin parameters. 2.2 The Path The path under i n v e s t i g a t i o n i s part of the Trans Canada Telephone System microwave network and i s located approximately 100 kilometers east of Vancouver, B.C., Canada. It i s coastal and mountainous i n nature, 41.3 k i l o - meters i n length and l i e s between s i t e elevations of 236 m and 1436 m above mean sea l e v e l . Because the path has an elevation d i f f e r e n t i a l of 1227 m and an annual average r a i n f a l l of 1600 mm/yr. , there i s a high p r o b a b i l i t y that the 0°C isotherm (and hence bright band) w i l l exist at an intermediate eleva- ti o n between the transmitter and receiver s i t e s . The geographical layout and p r o f i l e of the path are shown i n Figures 2.0 and 2.1 respectively. Photo- graphs are also provided looking d i r e c t l y down the path from the transmitter s i t e (Figure 2.2(a)) and d i r e c t l y up the path from the receiver s i t e (Figure 2.2(b)). 2.3 Received Signal Monitoring At the receiver s i t e , s i g n a l l e v e l s from f i v e microwave channels are monitored and sampled at a rate of 10 Hz. These were selected on the basis of obtaining maximum information with respect to broadband and narrowband m u l t i - Figure 2.0 Geographical Layout of the Bright Band Propagation Experiment. Figure 2 .1 Path P r o f i l e : Ryder Lake to Dog Mountain. 29 a) From Transmitter Site: (Dog Mountain) Looking South indicates location of Receiver Site b) From Receiver Site: (Ryder Lake) Looking North "+" indicates location of Transmitter Site. Figure 2 . 2 Path Photographs. 30 path fading, copolar attenuation and cross-polar e f f e c t s . Four of the chan- nels are of horizontal p o l a r i z a t i o n and were selected at each end of the 4 and 7 GHz bands. The remaining channel i s at 4 GHz and has a v e r t i c a l p o l a r i z a - t i o n . S p e c i f i c information on the frequencies selected and the radio equipment used are given i n Figure 2.3. A sampling rate of 10 Hz has been selected as a compromise between the capacity of the high speed data l i n k and maintaining the i n t e g r i t y of the re- ceived signal data during fast fade events. Fade rates of 50 to 60 dB/sec have been observed on a s i m i l a r experimental l i n k i n B r i t i s h Columbia [57], Therefore, a 10 Hz receiver signal sampling rate has been chosen to avoid lo s i n g this fade information and yet maintain the data flow within the capa- c i t y of the data l i n k . The block diagrams are given for both the 4 and 7 GHz transmission sys- tems used i n this experiment as shown i n Figures 2.4 and 2.5 r e s p e c t i v e l y . These are used to calculate the received signal l e v e l s , fade margins and r e s u l t i n g annual outage p r o b a b i l i t i e s i n the transmission calculations of Table 2.0. In both the 4 and 7 GHz cases the measured and calculated received s i g n a l l e v e l s agree to within 1 dB. The r e s u l t i n g outage p r o b a b i l i t y due to propagation events i s estimated to be 4.4 minutes/year for the 4 GHz system and 31.6 minutes/year for the 7 GHz system. The received signa l l e v e l i s monitored from the Automatic Gain Control (AGC) feedback voltage which i s proportional to the magnitude of the incoming s i g n a l . The v a r i a t i o n of the AGC voltage versus receiver input signa l l e v e l i s given i n Appendix A for the f i v e microwave receivers monitored. 31 PARABOLIC HORIZONTAL HORN REFLECTOR FROM DOG MOUNTAIN * - SELECTED RECEIVER CHANNELS HORIZONTAL 878 C3 RADIO EQUIPMENT * 7142 MHz 7496.5 « MHz 7 GHz F R E Q U E N C Y P L A N MHz *• <!0!0 4090 4170 FROM DOG MOUNTAIN VERTICAL HORIZONTAL RADIO EQUIPMENT TO 2S TO 2S ^ J TO 2 J RA 3 RA 3 TD 2 TD 2S TO 2 MHz 3550 * 3630 3710 3790 * 3870 4 G H z F R E Q U E N C Y P L A N Figure 2.3 Frequency Selection Plan and Receiver Equipment used at Receiver S i t e . HORIZONTAL 4 0 / 0 M H Z Figure 2.4 4 GHz. Microwave Transmission Block Diagram tV/? /37 <S\ 7/42. O AfMZ o 0 TO ^SC£/t/£/ZS + 3 0 ^ 5 , 7/42.0 M/-/Z. Figure 2.5 7 GHz. Microwave Transmission System Block Diagram 34 Table 2.0 Microwave Transmission Calculations 1) Locations Dog Ryder Dog Ryder Mtn. Lake Mtn. Lake 2) Latitude °N 49°24'35" 49°06'52" 49°24,35" 49°06'52 3) Longitude °W 121033'28M 121°54'07" 121°33'28" 121°54'07 4) Elevation (meters) 1463m 235m 1463m 236m 5) Antenna Height (meters) 20m 20m 9m 8m 6) Azimuth (°T) 217.5 217.5 8) Frequency (MHz) 4010 7496.5 9) Path Length (km) 41.3 41.3 10) Path Attenuation (dB) 136.8 142.3 11) Misc. Losses (dB) 1.0 1.0 12) Transmission Line Type WR229 WR229 WR137 WRI 3 7 13) Transmission Line Loss 0.8 0.8 1.8 3.8 14) Circulator Loss 0.6 0.6 0.8 0.8 15) F i l t e r Loss - - -16) Connector Loss 0.4 0.4 0.6 0.6 17) Radome Loss 1.0 1.0 1.0 1.0 18) Total Loss (dB) -143.4 -153.7 19) Antenna Type Horn Horn Reflector Reflector Parabolic Parabolic 20) Antenna Gain (dBi) +39.5 +39.5 +42.9 +42.9 21) Transmitter Power (dBm) +33.0 +30.0 22) Received Signal Level -31.4 (-31.0 Measured) -37.9 (-38.5 Measun (18+20+21) 23) Receiver Threshold (dBm) -68.5 -69.5 24) Fade Margin (22-23) -37.1 (-37.5 Measured) 31.6 (-31.0 Measun 25) Propagation Availability % (Annual)* 99.9992 99.994 26) Annual Outage Estimate 4.4 Min/Year 31.6 Min/Year *The propagation ava i l a b i l i t y on line 25 has been calculated using the following formula [2,36,58]: Propagation Availability % =• 100[l-ab(6.0xl0~ 7xfxD 3xl0 (~ F / 1 0 ))] where a • Terrian roughness factor (1 « average) b • Climate Factor (1/4 •» normal temperate) f » frequency in Gigahertz D • distance in kilometers F • fade margin i n dB 35 CHAPTER III METEOROLOGICAL INSTRUMENTATION 3.1 System Design 3.1.1 Measurement C r i t e r i a In order to measure the ef f e c t s of copolar propagation through the bright band i t i s important to be able to monitor the presence of the 0°C isotherm along the path, to determine the thickness of the bright-band region and to measure the p r e c i p i t a t i o n rates through the band. The presence of the bright band can be detected by establishing the temperature d i f f e r e n t i a l between the transmitter and receiver s i t e s to see i f the 0°C isotherm i s included. The thickness of the bright-band region, once detected, i s then determined i n d i r e c t l y by establishing the temperature gradient through the 0°C isotherm. The p r e c i p i t a t i o n rates can be monitored d i r e c t l y through a network of r a i n gauges or i n d i r e c t l y using synthetic storm techniques [59-62]. The l a t t e r requires the measurement of windspeed and wind d i r e c t i o n , preferably at several points along the path to determine p r e c i p i t a t i o n c e l l locations as a f u n c t i o n of time. 3.1.2 Site Selection In order to meet the measurement c r i t e r i a of obtaining detailed temper- ature gradient, point r a i n f a l l rate information and wind information, f i v e weather stations have been selected between transmitter and receiver s i t e s . These s i t e s are shown i n F i g . 3.0 with t h e i r geographical and functional s i t e 36 DOG MOUNTAIN (V ) TRANSMIT SITE RECEIVE SITE E L E V ' 256 in Figure 3.0 Measurement System Layout. information provided i n Table 3.0. Detailed s i t e plans, equipment configura- tions and s i t e photographs are available for each s i t e i n Appendix C. The temperature gradient can be determined from the three s i t e s located at beam elevation, with one at the transmitter s i t e (V), one at mid-path (III) (at suitable elevation) and one at the receiver s i t e ( I ) . The point r a i n f a l l rate information i s obtained from these as well as from the two remaining weather stations (II and IV) situated at intermediate s i t e s along the v a l l e y f l o o r beneath the path. These intermediate s i t e s are valuable since they allow the measurement of the melted p r e c i p i t a t i o n rates d i r e c t l y under the Table 3.0 Geographical and Functional Site Details SITE Coordinates & Elevation Data Collected I. Ryder Lake 49 06* 52" N. Lat. 121 54' 07" W. Long. Elevation: 236 m Receiver Signals 2-4 GHz. Hor. Pol 1- 4 GHz. Ver. Pol 2- 7 GHz. Hor. Pol Meteorological II. Agassiz Experi- mental 49 14' 40" N. Lat. 121 47' 18" W. Long. Elevation: 15 m Meteorological III. Bear Mtn. 49 18' 25" N. Lat. 121 41' 30" W. Long. Elevation: 945 m Meteorological IV. Ruby Creek 49 21' 15" N. Lat. 121 36' 45" W. Long. Elevation: 31 m Meteorological V. Dog. Mtn. 49 24* 35" N. Lat. 121 33' 28" W. Long. Elevation: 1463 m Meteorological Primary Importance Multiplex's F i e l d data Receiver Site Receiver Signals Rain Rate Temperature Rain Rate Intermediate Site on Valley Floor Temperature Intermediate Site at Path Elevation Rain Rate Intermediate Site on Valley Floor Temperature Transmitter Site 38 path during bright band a c t i v i t y . This i s possible due to t h e i r much lower and hence warmer s i t e elevations. F i g . 3.1 provides a cross-section view of the path showing the r e l a t i v e locations of the weather station s i t e s selected. 0 5 10 15 20 25 30 35 40 41.5 • DISTANCE IN KILOMETRES Figure 3.1 Path Cross-section Showing Relative Locations of the Weather Station Sites. 39 3.2 Meteorological Measurements 3.2.1 Rain The rain gauges used i n this thesis are of the tipping-bucket variety capable of measuring point rain rates of up to 400mm/hour. Accurate measure- ment above this rate i s not important because of the low probability of such events in the path area [63,64]. The rain bucket tips after each 0.318mm of rain which generates a pulse by momentarily closing a glass encapsulated reed switch relay. The pulse thus generated i s latched using a signal conditioning c i r c u i t for sampling by the microprocessor after which time the latch i s cleared to await the next bucket t i p . For a detailed description of the signal conditioning c i r c u i t with respect to c i r c u i t schematics, physical specifications and photograph refer to Appendix E. With the path being located approximately 100 kilometers east of Vancouver, i t was essential that the tipping buckets require low maintenance. For this reason a molded p l a s t i c unit which i s inherently corrosion resistant was acquired. Appendix D-3 provides a detailed description and photograph of this unit. Five rain gauges were i n s t a l l e d along the path at each of the weather station s i t e s . Figure 3.2 and Table 3.1 show the i n t e r - s i t e spacings and the spacings as a function of t o t a l path length. 40 RYDER AGASSIZ BEAR RUBY DOG LAKE EXPERIMENTAL MOUNTAIN CREEK MOUNTAIN FARM . I 1 1 1 1 0.0 17.83 24.20 33.71 41.25 DISTANCE IN K I L O M E T R E S Figure 3.2 Weather Station Inter-Site Distances. Table 3.1 Inter-Site Distances as a Function of Path Length Ryder Agassiz Bear Ruby Dog Lake Exp.Farm Mtn. Creek Mtn. Ryder Lake - .43 .59 .82 1.0 Agassiz Exp. Farm - .15 .39 .57 Bear Mountain - .23 .41 Ruby Creek .18 Dog Mountain - The t o t a l r a i n rate for the path i s determined using a distance weighted average from the r a i n rates at each of the s i t e s . The rai n rate between any two i n t e r v a l bucket t i p s at a working gauge i s f i r s t determined by equation 3-1. RR = tJ-P s l z e n ^\ ^ s i t e 1 A T ( 3 _ 1 ) where t i p Tip Size = 0.318mm AT^p = time i n t e r v a l between two t i p s . 41 Then "path averaged r a i n rate" (RR path) calculated using equation (3-2). (RR _ , + RR . .) x (% Path) ,„ .. . D D _ s i t e 1 s i t e 2' ' s i t e 1 - s i t e 2 path ' 2 (RR . „ + RR _) x (% Path) . . , s i t e 2 s i t e 3 s i t e 1 - s i t e 2 2 H~ • • • • + (RR . k .. n + RR „) x (% Path) , s i t e N-1 s i t e N s i t e N-1 - Site N It i s important to calculate this r a i n rate with only, those gauges which are operational and not affected by accumulations of snow. An attempt has been made to minimize errors due to these factors by re j e c t i n g r a i n information from gauges where no a c t i v i t y i s observed during the passage of a p r e c i p i t a t i o n event. 3.2.2 Temperature Transducer Temperature transducers were placed at a l l the s i t e s to measure the out- side ambient temperature. As a system, these transducers determine the pres- ence of the 0°C isotherm and hence the bright band along the path as well as i n d i r e c t l y determining the thickness of the bright band region by esta b l i s h i n g the temperature gradient between transmitter and receiver s i t e elevations. Their design i s based on the l i n e a r temperature c o e f f i c i e n t of a semi- conductor junction when forward biased with a constant current source. The transducer i s conditioned to provide a switch selectable output of 0.01 vo l t s per degree centigrade or per degree fahrenheit allowing for single point c a l i - bration. Further d e t a i l s are given i n Appendix D describing the unit as well as providing the c a l i b r a t i o n procedure. 4 2 3.2.3 Wind V e l o c i t y and Wind Di r e c t i o n Transducer A l l the s i t e s , except Ruby Creek and Bear Mountain, are equipped with a propeller type anemometer with the purpose of monitoring both wind v e l o c i t y and wind d i r e c t i o n . The v e l o c i t y i s derived from the output of the unit's propeller-driven dc generator which exhibits a l i n e a r windspeed-voltage char- a c t e r i s t i c . The azimuth, on the other hand, i s provided by the l i n e a r output voltage which i s proportional to the angle r e l a t i v e to true north based on the output of a gear-driven potentiometer. The wind v e l o c i t y and wind speed information obtained from these trans- ducers i s required to be able to apply synthetic storm techniques [59-62] i n the processing of the propagation data for research purposes. More detailed information on the anemometer unit i s given i n Appendix D. 3.3 Meteorological-Data Sampling The basic ac powered weather s i t e s of the Agassiz Experimental Farm, Ruby Creek and Dog Mountain are each equipped with one U.B.C. Weatherlog Micropro- cessor and one Meteorological Signal Conditioning Unit. A photograph of these units i s presented i n Figure 3.3. Details on these units i s given i n Appendix I for the weatherlog processor and i n Appendix E for the signal conditioning u n i t . 43 Figure 3.3 Photograph of the U.B.C. Weatherlog Microprocessor and Meteorological Signal Conditioning Unit. The weatherlog has been programmed so that i t samples the meteorological variables of wind d i r e c t i o n , wind v e l o c i t y , temperature and r a i n f a l l on a one- second software-determined i n t e r v a l . The output of the unit i s a voice f r e - quency FSK modulated s i g n a l . The sampling of the meteorological variables at the Ryder Lake and Bear Mountain sites follow the same "weatherlog" system design, but use other microprocessor configurations at these s i t e s due to d i f f e r i n g monitoring requirements and power a v a i l a b i l i t y c o n s t r a i n t s . In choosing the optimum sampling rate, a trade-off i s made between l o s i n g information of f a s t varying v a r i a b l e s , transmitting data wi t h i n the maximum l i n k capacity and minimizing the design complexity of the s i g n a l conditioning unit. The compromise reached was to use a 1 Hz sampling rate, to transmit the data at 110 bps and design the conditioning unit to l a t c h bucket t i p s u n t i l 44 sampled. This 'is a reasonable compromise since the information for a l l the variables except the fa s t e s t changes i n wind v e l o c i t y and wind d i r e c t i o n are retained and l i t t l e information i s l o s t i n the most important variables of temperature or r a i n f a l l . This leaves a growth allowances of 1 2 0 % for future data requirements as addi t i o n a l transducers are needed. 45 CHAPTER IV DATA ACQUISITION SYSTEM 4.1 Design C r i t e r i a for a Real Time Data A c q u i s i t i o n System The data a c q u i s i t i o n system must be capable of acquiring i n re a l time the sampled meteorological and received signal l e v e l data and then be able to store this data i n a format compatible for processing on a general purpose computer. To do this the data must be routed from the s i t e s , shown i n Figure 3.0, through a series of data l i n k s to arri v e at the University of B r i t i s h Columbia for r e a l time c o r r e l a t i o n . The design of the data a c q u i s i t i o n system comprises three basic areas: a I) The on-site data a c q u i s i t i o n II) The data c o l l e c t i o n network III) The real-time storage, formatting and coordination of the data. Figure 4.0 shows the data a c q u i s i t i o n system block diagram with each of the three component areas i d e n t i f i e d . Component area I, the on-site data a c q u i s i - t i o n , deals with the type of data, the analog to d i g i t a l (A/D) sampling rates and the interface to the outgoing data l i n k . Component area I I , the data- c o l l e c t i o n network, i s concerned with minimizing system cost and delay time under ce r t a i n l i n k - c a p a c i t y , link-flow and routing contraints. Component area I I I , the real-time storage, formatting and coordination of the data, i s con- cerned with the time c o r r e l a t i o n of the incoming data and the processing of the data into suitable time series and d i s t r i b u t i o n series storage formats. 46 SITE NAME RECEIVED SIGNAL LEVELS (AGO C H A N N E L T Y P E MICROWAVE PATH UNIVERSITY OF BRITISH COLUMBIA ( U.B.C.} RAIN RATE RYOER TEMPERATURE LAKE WIND SPEED l — WIND DIREC. RR — - WS WD RR — — BEAR T — * MOUNTAIN MICRO PPO;ESSOR| (yuP) SIGNAL L E V E L C A B L E DATA METEOROLOGICAL C A B L E 100 tt>j DOG MOUNTAIN AGASSIZ EXPERIMENTAL FARM RUBY C R E E K Z1 P H M MICROWAVE ^ 1 M M W T x VHF M ws- wo- RR - T - H M VOICE CIRCUIT M P M M VHF H M RYDER L A K E TO UBC DATA LINK VIDEO TERMINAL AREA I - A R E A II AREA rr U.B.C. COMPUTING C E N T R E ASEA m Figure 4.0 The Data Acquisition System Block Diagram With Component Areas Identified. 47 4.2 Site Selection 4.2.1 Received Signal Site The Ryder Lake data a c q u i s i t i o n equipment, which monitors the received s i g n a l l e v e l s , must provide s u f f i c i e n t samples and quantization resolution to accurately reconstruct the received s i g n a l l e v e l s from the outgoing data stream. This applies p a r t i c u l a r l y to fast fades which have previously been observed at rates up to 50-60 dB per second on s i m i l a r paths i n the region [57]. The received signal data transmitted must also allow easy formatting, must be sent at a rate which i s equal to or less than the outgoing l i n k capa- c i t y and must maintain o v e r a l l system timing. To meet these design objec- t i v e s , an accurately determined sampling rate of 10 Hz was chosen, the received signal l e v e l s were conditioned to +0-5 volts matching the input range of the A/D and the number of outputted quantization b i t s were limited to eight b i t s to meet system data formats. The r e s u l t i n g data rate of 600 b i t s per second from the f i v e monitored received s i g n a l l e v e l s i s calculated as follows: (One - 8 b i t synch byte + f i v e - 8 b i t receiver samples + 1 s t a r t bit/byte + 1 stop bit/byte) a l l times 10 sampling cycles per second = 600 bps. For more information concerning the receiver signal conditioning units refer to Appendix E, and for a detailed d e s c r i p t i o n of the Ryder Lake received s i g n a l l e v e l data a c q u i s i t i o n microprocessor refer to Appendix I. 48 4.2.2 Meteorological Sites The purpose of the data a c q u i s i t i o n equipment at the meteorological s i t e s i s to sample the weather variables of wind d i r e c t i o n , wind v e l o c i t y , tempera- ture and r a i n f a l l at one second i n t e r v a l s and send these back v i a the s i t e ' s outgoing communication channel into the data c o l l e c t i o n network. The data a c q u i s i t i o n equipment consists b a s i c a l l y of a microprocessor which coordinates the sampling (see Appendix I ) , a meteorological signal conditioning unit which provides a f u l l range, +0-5 v o l t , input to the A/D (see Appendix E) and a modem which encodes the data as a frequency s h i f t keyed (FSK) output to the data channel (see Appendix H). The outgoing data rate of 110 bps was chosen keeping future data growth requirements in mind. At present, the data sent for a one second sampling cycle includes four - 8 b i t bytes, one - 8 b i t synchronization byte as well as one star t b i t and one stop b i t for each of these bytes to give a net data rate of 50 bps. This leaves an excess capacity of 60 bps for future use. The type of communications channels used from the meteorological s i t e s are shown i n the system block diagram of Figure 4.0 and includes VHF radio channels from the Bear Mountain (III) and Ruby Creek (IV) s i t e s , a microwave radio channel from Dog Mountain (V), a telephone c i r c u i t from the Agassiz Experimental Farm (II) and a cable at Ryder Lake ( I ) . The organization of these communication channels into a data c o l l e c t i o n network i s the subject of the next se c t i o n . 49 4.3 Data C o l l e c t i o n Network Design 4.3.1 Data S t a t i s t i c s From section 4.2 i t i s evident that the data c o l l e c t i o n system must handle the s t a t i s t i c a l l y - d i f f e r e n t receiver and meteorological data packets. A packet of receiver signal l e v e l data i s sent from s i t e I every one-tenth of a second, consisting of 5 samples (the 3550, 3790, 4010, 7142.0 and 7496.5 GHz AGC voltages), followed by a synchronization byte. The net a r r i v a l rate for this receiver amplitude data including the start and stop b i t s i s 600 bps. A data packet of meteorological data, on the other hand, i s sent from each of the f i v e weather station s i t e s , consisting of four samples (wind d i r e c t i o n , wind v e l o c i t y , temperature and r a i n f a l l ) , followed by synchronization byte. The net data rate for the meteorological data on a per s i t e basis including s t a r t and stop b i t s i s 50 bps. 4.3.2 Link Capacities In order to define a network topology, the l i n k capacities and cost for each of the outgoing communication channels were considered. Several a l t e r n a - tives exist for each s i t e but the l i n k and associated communications channel providing for the best cost-capacity trade-off are as follows: i ) Ryder Lake to UBC (telephone c i r c u i t ) This l i n k was r e s t r i c t e d to an order-wire type telephone c i r c u i t chan- nel available from the telephone company's e x i s t i n g network. This l i n k corresponds to a conditioned telephone c i r c u i t with a data capacity of 2400 bps. 50 i i ) Other Telephone C i r c u i t s Other telephone c i r c u i t channels were e a s i l y obtained from the Agassiz Experimental Farm and from the Dog Mountain s i t e (via microwave) to the Ryder Lake s i t e . The c i r c u i t from Agassiz i s a dedicated unconditioned telephone c i r c u i t through the regions switched network with a capacity of 1200 bps (see Figure B-5). The Dog Mountain c i r c u i t uses the lower frequency portion of a network alarm channel and has maximum capacity of 300 bps (see Figure B-4). i i i ) Radio Channels Two VHF radio licenses were obtained to provide the remaining two com- munication channels from Ruby Creek and Bear Mountain to Ryder Lake. These u t i l i z e the voice frequency pass band of the VHF radios providing a maximum l i n k capacity of 600 bps. For detailed information on a l l these data l i n k s please refer to Appendix B where the i r c i r c u i t schematics, path p r o f i l e s and transmission calculations are given. 4.3.3 Node Considerations Individual node design must be consistent with the o v e r a l l data acqui- s i t i o n objective to coordinate and time correlate a l l c o l l e c t e d data. This implies that no data storage or buffers at any of the c o l l e c t o r or a c q u i s i t i o n nodes can delay the a r r i v a l of data at the storage node (UBC) and that the sampled data should be sent immediately (as i t i s monitored). 51 4.3.4 Implementation of the Network Topology The f i n a l data a c q u i s i t i o n topology was l a r g e l y determined by the con- s t r a i n t s of cost, capacity and a v a i l a b i l i t y of the communication channels be- tween nodes. The r e s u l t i n g topology i s presented i n Figure 4.1. Figure 4.1 Data C o l l e c t i o n Network Topology 52 4.4 Real Time Data Storage 4.4.1 Microprocessor Considerations The a c q u i s i t i o n system data storage microprocessor i s located at UBC and handles the administrative tasks of tagging the data with r e a l time as i t a r r i v e s , of organizing the data into useful data storage formats and of out- putting the processed data onto a magnetic tape and onto a video monitor. This processor's main objective i s to reduce the volume of data to manageable leve l s by s e l e c t i n g only desirable time series i n t e r v a l s as well as compress- ing the data using hourly d i s t r i b u t i o n s . This technique reduces the stored data volume to approximately 10% of the t o t a l incoming data so that under normal operating conditions a 4.5 megabyte data cassette w i l l record approxi- mately 10 days of system output. To make i t e f f e c t i v e , the UBC computer i s interfaced using RS 232 ports and uses two CPU's to d i s t r i b u t e the tasks of processing, formatting and data s e l e c t i o n . A video monitor has been added to allow the r e a l time display of incoming data as shown i n Figure 4.2. Refer to Appendix I for a complete desc r i p t i o n of the UBC microprocessor hardware and to Appendix J for a d i s - cussion of the UBC processor programs. 4.4.2 Data Storage Formats The data which arrives at UBC i s stored i n two basic formats; one for time series data and another for d i s t r i b u t i o n data. The time series data includes a l l the a r r i v i n g data whereas the d i s t r i b u t i o n data format provides a cumulative hourly t o t a l of each variable for the number of samples taken at a given value. The time series data i s only stored when an event occurs and |INE 63 1] 15 57 51 ws ei ei MI <w ee MY 44 44 SA 44 06 •W 55 53 45 <N ee MSZ M> 61 ta 94 61 n.n. Cl 16 81 <n ei wt.n. C7 02 D7 13 14 C4 05 N 13 14 C5 02 05 13 14 Cb 05 03 13 14 CJ 02 08 13 14 C5 03 05 13 14 C4 05 03 13 14 C8 02 03 13 14 C4 05 Ob 13 14 C4 02 07 13 14 Figure 4.2 Photograph of Video Terminal Displaying Incoming Data therefore time series dumps are random i n nature and vary i n length whereas the d i s t r i b u t i o n buffer i s dumped hourly and has a fixed length of 3890 bytes. The time series data i s organized into a queue comprised of 12 complete one second blocks where each one second block i s composed of 80 bytes. The d i s - t r i b u t i o n data i s comprised of 5 types of data (wind d i r e c t i o n , wind v e l o c i t y , temperature, r a i n f a l l and receiver amplitude) with 5 double byte d i s t r i b u t i o n s for each meteorological data type and 5 double byte d i s t r i b u t i o n s for each receiver amplitude. Of these, each meteorological d i s t r i b u t i o n has 64 double byte "bins" and each receiver signal amplitude d i s t r i b u t i o n has 128 double byte "bins". Each bin represents a certain sampled value. The format used for the time series queue i s given i n Table J-2 and the format for the d i s - t r i b u t i o n series queue i s provided i n Table J-3 of Appendix J . 54 4.5 Allowance f o r Future Data Requirements The present data a c q u i s i t i o n system design has l e f t a substantial amount of data capacity unused as shown i n Table 4.0. This was intended to provide the c a p a b i l i t y of adding add i t i o n a l propagation experiments to the network as the program progresses. If the assumption i s made that the network capacity i s l a r g e l y determined by the Ryder Lake to UBC l i n k then there i s 65% or 1550 bps of unused data handling capacity. This i s calculated based on using e f f e c t i v e t o t a l data rates since a s t a t i s t i c a l data multiplex i s used on the Ryder Lake to UBC l i n k . Table 4.0 Data Ac q u i s i t i o n System Link Capacities CAPACITY CAPACITY TOTAL USED UNUSED LINK CAPACITY bps % bps % 1) Ryder to UBC 2400 850 35 1550 65 2) Dog to Ryder 300 50 17 250 83 3) Ruby to Ryder 600 50 8 550 92 4) Bear to Ryder 600 50 8 550 92 5) Agassiz to Ryder 900 50 6 850 94 4.6 An Alternate Data A c q u i s i t i o n System Using Chart Recorders Prior to the implementation of the automated data a c q u i s i t i o n system a system of chart recorders were used to monitor two 7 GHz microwave channels at the receive s i t e and meteorological variables from four stations located along the path. This system produced the f i r s t preliminary results which were pre- sented i n two papers [65,66] and are given i n t h i s thesis i n section 6.1. 55 CHAPTER V DATA BASE MANAGEMENT SYSTEM 5.1 Sp e c i f i c a t i o n s The data base management system (DBMS) has been developed as part of this research to provide an e f f i c i e n t means, through the use of a general purpose computer, to handle the analysis and storage of large volumes of meteoro- l o g i c a l and propagation data. Within the o v e r a l l data handling problem, as far as the bright-band research i s concerned, DBMS takes over data handling at the point where the 800 bpi, 9-track raw data tape i s transfered from the NOVA 840 to the UBC computing center. This interface i s i l l u s t r a t e d i n the data system flow chart of Figure 5.0. In developing the s p e c i f i c a t i o n s for DBMS, several general issues were considered. F i r s t , DBMS must be easy to use so that a researcher with minimal f a m i l i a r i t y to MTS can u t i l i z e i t . Second, DBMS must be f l e x i b i l e to allow d i f f e r e n t propagation data series formats to be handled and yet require a minimum amount of software r e v i s i o n to incorporate the necessary changes. Third, DBMS must make maximum use of ex i s t i n g software packages developed for the 74 GHz experiment [66,70] and the l i b r a r y routines' resident on the MTS system. F i n a l l y , DBMS must use "time" as the universal f i e l d of access to system data records since i t i s inherently a common variable for a l l propagation data. > In addition to these general s p e c i f i c a t i o n s DBMS must s a t i s f y four func- t i o n a l requirements: 1. It must enter new data onto the system (ENTER), fmt fro'-ofty .co / \ fmtt<or*/*g><*J^\ fTf***er0f<yco7\ Aw,'M^/«lf lA J V aarv J V data * > \^ ^ 56 *y</Cr Lit. (eeoc) freceiver ^ eft mux ^ PATLOG UBC (eeoo) DATA ACOU/3ITIOA/ DATA SASE / . DBMS CA m daM'/A4 TS) Jo* STAT/ST'tCAl €r GRAPHICAL A/VALfS'S ure 5.0 The Bright Band Experiment Data System Flow Chart 57 2. It must be capable of li m i t e d perusal and data s e l e c t i o n from summarized r e s u l t s (SCAN), 3. It must be able to extract s p e c i f i e d data records from the data base f o r independent analysis (EXTRACT), 4. It must allow easy ap p l i c a t i o n of graphical and s t a t i s t i c a l analy- s i s routines (PLOT). For a detailed description of the ENTER, the SCAN, the EXTRACT and the (PLOT) routines, refer to Appendix K. 5.2 Design Considerations f o r DBMS Relative to Exi s t i n g and Future Systems In the design of DBMS, several other experiments and data base storage systems ( i n progress or proposed) were considered i n r e l a t i o n to each other as shown i n Figure 5.1. At the present time the 74 GHz and the bright band experiments contribute data to the UBC data base while the B.C. Telephone Company monitoring system develops i t s own data base. In the future, the proposed d i g i t a l radio propagation experiment w i l l contribute data to both these data bases as well as to the one at the Communications Research Centre, Ottawa, Ontario. Therefore, i t would be desirable to transfer data between the systems i n order to allow researchers at one loc a t i o n to have access to data from the other. There are several methods which can be used to transfer these data between systems, as i l l u s t r a t e d i n Figure 5.1. The most r e l i a b l e method, which i s also the most u n i v e r s a l , i s to transfer the raw data cassettes between systems. This method i s desirable since the data processing would be under the control of the researcher who wants the r e s u l t s . Another reason, adding to this method's u n i v e r s a l i t y i s that the cassette recording formats 58 74 R A W G H Z P/ITA E N T E R S A I N I 1 I C R C P/OITAL | I &AIY R4TA ac TCL R A W D A T A PP£SE/VrAT/OA/ /POL/r/A/fS PPfSEA/TAT/OA/ POur/A/ES Figure 5.1 DBMS i n Relation to Other Propagation Data Management Systems. 59 are the same as other Canadian propagation experiments. The most e f f i c i e n t method to interface the two data bases would be to transfer the data on magnetic tapes between computing centers and use a bridg- ing routine to reformat the data. This method i s workable provided a large number of bridging routines are not required and the number of tapes to be transferred i s not excessive. 5.3 A System Description of DBMS 5.3.1 Data Transfer and Handling DBMS starts inputting data by evoking the "ENTER" mode. This inputs raw data of either time series or d i s t r i b u t i o n series formats for processing from an unlabelled magnetic tape, previously transferred on the NOVA system at a density of 800 bpi i n half word hexidecimal format from the cassettes. Once inputted the data i s entered on a disc f i l e . For the d i s t r i b u t i o n series data one preprocessing scan i s made and for the time series data two preprocessing scans are made. In the l a t t e r case the f i r s t scan processes the bucket-tip information to determine rain rates and the second scan converts the data using scaling factors and look-up tables to provide the engineering u n i t s . The converted d i s c f i l e s can then be outputted to a l a b e l l e d 6450 bpi data tape using the MTS "FILESAVE" system or further processed by evoking the "PLOT" mode to display the data i n one of several options. These include time seri e s plots of windspeed, temperature, temperature gradient, d i f f e r e n t i a l temperature and receiver sign a l strength. Figure 5.2 gives a block diagram of the DBMS software system to process the time series data. At the present time the routines to process the d i s - t r i b u t i o n series data have yet to be implemented. R DBMS OPTIONS 1, ENTER 2, PLOT 3, SCAN 4, EXTRACT PLOT OPTIONS 1, lRx, RAIN 2, 1 TEMP, lRx 3, lRx, 1 WIND 4, 2Rx 1,3 SCALE FACTORS SELECT VA~IA3LT PLOTSEE 3,4 • TEMP OPTIONS 1,1 TEMP, lRx 2, dT/dt, lRx 3, T:SITE, lRx 4, dT/dH, lRx Rx OPTIONS 1, N. RES, 1 SEC. AVE. 2, HIGH RES. lflO SEC. ENTER OPTIONS 1, TAPE 2, PERM FILE 3, PERM FILE 4, TEMP FILE 5, TEMP FILE "EAD DATA CONVERT DATA OUTPuT TO-DAT/. OUTPUT Figure 5.2 User Flowchart to Process time series data on the DBMS software system. 61 5.3.2 Estimate of DBMS Data Volumes Size estimates for the bright-band data base are of i n t e r e s t . The amount of data acquired i s determined mainly by the event c r i t e r i a set to record time series data. Assuming that the event c r i t e r i a i s set so that on an average, 5% of the time series data i s recorded the corresponding yearly data volume estimates are presented i n Table 5.0. It i s estimated that two 6250 bpi 2400 foot magnetic tapes per year i s necessary to store the d i s t r i b u t i o n data and six 6250 bpi 2400 foot magnetic tapes per year are required to store the time series data. Table 5.0 DBMS Data Volume Estimates D i s t r i b u t i o n Volumes ( i n bytes) Time Series Volumes (@ 5% i n bytes 3,890/hr. 93,360/day 653,520/wk. 2,800,800/mo. 33,609,600/yr. 14,580/hr. 349,920/day 2,449,440/wk. 10,497.600/mo. 125,971,200/yr. 62 CHAPTER VI' RESULTS 6.0 Introduction Results are presented from two series of measurements. The f i r s t series were taken i n early 1980 using chart recorders from which two events are analyzed e x h i b i t i n g opposite dynamics i n the movement of the 0°C isotherm. These results are presented i n section 6.1. The second series of measurements were taken i n early 1980 and uses the remote telemetry system as described i n Chapters I I , IV and V. Results from three events are analysed i n section 6.3 showing various aspects of bright band propagation phenomenon. 6.1 Some I n i t i a l Results Obtained Using Chart Recordings Prior to completion of the telemetry based system data was co l l e c t e d from January 3, 1980 to March 30, 1980, using chart recorders. During t h i s time a number of events were recorded showing the presence of bright-band e f f e c t s . Table 6.0 shows two sets of data taken during separate bright-band events. The two events selected show opposite dynamics associated with the v e r t i - c a l movement of the 0°C isotherm. Charts of the received signal data are shown i n Figure 6.1 along with the corresponding sampling i n t e r v a l s that were used i n Table 6.0 and 6.1. Event "A", recorded on January 11-12, 1980, shows the 0°C isotherm r i s i n g i n elevation from below the path while event "B", recorded on February 2, 1980, shows the 0°C isotherm descending i n elevation from above the path. The presence of the bright band i s v e r i f i e d by tempera- ture recordings and r a i n gauge a c t i v i t y at the transmitter and receiver s i t e s . Figure 6.0 Recordings of Received Signal at 7 GHz During Bright-Band Propagation a) Event "A" (January 11-12, 1980) b) Event "B" (February 2, 1980) Table 6.0 Preliminary Results Average Average Attenuation i n dB Event & Rain Rate Excess Sample No. (mm/hr) Meas. Rain* Atten. "A" 1 13.4 16.6 4.3 12.3 2 9.5 13.5 2.3 11.2 3 13.4 20.0 4.3 15.7 4 3.8 9.0 1.0 8.0 5 13.3 15.5 4.3 11.2 "B" 1 8.1 2.9 2.4 0.5 2 8.0 3.8 2.4 1.4 3 17.7 6.9 6.2 0.7 4 19.1 10.9 6.8 4.1 5 9.3 15.0 2.5 12.5 6 7.2 16.6 2.1 14.5 7 5.5 17.4 1.6 15.8 8 4.3 10.4 1.1 9.3 *Derived using the Laws and Parson D i s t r i b u t i o n for 0°C Table 6.1 Bright-Band Excess Attenuation Ratio (EAR) Results Average Rain Bright-band Excess Attenuation Event No. Attenuation Attenuation Ratio dB/km dB/km (EAR) "A" 1 0.104 0.851 8.2 2 0.056 0.775 13.9 3 0.104 1.086 10.5 4 0.024 0.553 23.1 5 0.104 0.775 7.5 "B" 1 0.058 0.036 0.6* 2 0.058 0.097 1.8* 3 0.150 0.048 0.3* 4 0.164 0.291 1.7* 5 0.060 0.865 13.1 6 0.051 1.003 19.7 7 0.039 1.093 28.0 8 0.027 0.643 23.8 *The 0°C isotherm i s above the transmitter s i t e for these data points. 65 These results show that the measured attenuation i s considerably above that predicted by a ra i n model and, at t h i s frequency, could only be att r i b u t e d to excess bright-band attenuation. The radar r e f l e c t i v i t y p r o f i l e s presented by Dissanayake and McEwan [44] show that the bright band can be ex- pected to occur for approximately 35% of the t o t a l path length. In this t h e s i s , the excess attenuation has been defined i n terms of a r a t i o of the excess attenuation i n dB/km att r i b u t a b l e to bright band divided by the rain attenuation i n dB/km using the Laws and Parson d i s t r i b u t i o n at 0°C [23], The r a t i o thus defined w i l l be referred to as the Excess Attenuation Ratio (EAR). The EAR's for the corresponding sampling i n t e r v a l s used i n Table 6.0 have been calculated and are presented i n Table 6.1. The excess attenuation ra t i o s for event "A" are generally lower than for event "B", both being determined assuming r a i n along the whole path. This may be explained as follows. In event "B" the 0°C isotherm started from above the transmitter s i t e with rain attenuation occurring along the whole path. Since wet snow or sleet would have been f a l l i n g at the transmitter s i t e during event "B", a contribution to the excess attenuation may also have come from accumu- la t i o n s on the radome. Taking these factors into account, the EAR's for event "A" would be lower and more i n l i n e with the EAR's found i n event "A". Radome accumulations for event "A" would have been minimal since "dry" snow was present at the transmitter s i t e and r a i n was f a l l i n g at the receiver s i t e f o r the sampling i n t e r v a l s selected. In both events, rapid s c i n t i l l a t i o n type fl u c t u a t i o n s of 5 to 10 Hz appeared on the received s i g n a l recordings. These fluctuations coincided with the occurrence of heavy bright-band fading and were estimated to be up to 15 66 dB i n depth. It has been suggested that these fast fades are due to r e f r a c - t i v e multipath as a result of propagation through the bright band region.* Although these spikes were present i n the recordings, the measured attenuation i n Table 6.0 was averaged along a baseline assuming that the spikes were not present. In order to study the cause of these s c i n t i l l a t i o n s i n more d e t a i l , to determine the bright-band EAR's with greater resolution and to minimize errors due to radome snow accumulation, an improved experimental design based on remote telemetry was implemented. A description of this improved measure- ment system has been presented i n Chapters I I , IV and V and some preliminary re s u l t s from t h i s system are given i n Section 6.2. 6.2 Remote Telemetry Results Showing Bright Band Propagation 6.2.1 January 23, 1982, 7:30-11:30 p.m. These re s u l t s were taken a f t e r a major storm front moved easterly through the path during a period of evenly d i s t r i b u t e d wide spread p r e c i p i t a t i o n . An increase i n attenuation .is evident as the 0°C isotherm moves into the path as shown i n Figure 6.1. The p r e c i p i t a t i o n rates were measured for the decaying portion of the event as shown by the r a i n rate and attenuation plots i n Figure 6.3. Excess Attenuation Ratios (EAR's) were calculated f or the sampling points shown i n Figure 6.2 and the r e s u l t s are presented i n Tables 6.2 and 6.3. These range from 10.4 to 19.8 and agree favourably to the EAR of 15 predicted by theory [50]. The presence of the bright band was v e r i f i e d by temperature recordings at the transmitter and receiver s i t e s . * Private discussions with R.K. Crane at the URSI, Commission F, Symposium held at Lennoxville, Quebec, May 1980. 67 Figure 6.1 The Agassiz Temperature and 7.142 GHz Signals Versus Time 68 Figure 6.2 Agassiz Rain Rate and The 7.496 GHz Signal Level Versus Time 69 Table 6.2 January 23, 1982 Results (7 GHz) Average Average Attenuation i n dB Event & Rain Rate Excess Sample No. (mm/hr) Meas. Rain* Atten. 1 4.4 8.8 1.5 7.3 2 4.4 7.8 1.5 6.3 3 3.5 7.1 1.1 6.0, 4 4.4 6.9 1.5 5.4 5 1.3 3.0 0.4 0.2 *Derived using the Laws and Parson D i s t r i b u t i o n f o r 0°C Table 6.3 Bright-Band Excess Attenuation Ratio (EAR) Results Average Rain Bright-band Excess Attenuation Event & Attenuation Attenuation Ratio Sample No. dB/km dB/km (EAR) 1 0.036 0.51 14.0 2 0.036 0.44 12.1 3 0.027 0.42 15.4 4 0.036 0.37 10.4 5 0.009 0.18 19.8 *The 0°C isotherm i s above the transmitter s i t e for these data points. These results show that the measured attenuation i s considerably above that predicted by a r a i n model and again as i n the chart recordings could only be at t r i b u t e d at th i s frequency to excess bright-band attenuation. Although r a i n information was taken at only one s i t e the uniform and widespread nature of th i s event's p r e c i p i t a t i o n gives consistent results with theory. 70 In t h i s event which i s s i m i l a r to the l a t e r part of event B i n Figure 6.0, no rapid s c i n t i l l a t i o n type fluctuations were observed. This corre- sponded to gradual changes i n temperature over t h i s period. 6.2.2 January 23, 1982, 2:00-4:30 p.m. The system front for the event on January 23, 1982, passed through the microwave l i n k between 2:00 and 4:30 p.m. producing fades of up to 30 dB on the 7 GHz receivers and up to 19 dB on the 4 GHz receivers, as shown i n Figure 6.3. The bright band was present along the path as indicated by the tempera- ture recordings for the Dog Mountain transmitter s i t e and the Ryder Lake receiver s i t e i n Figures 6.4 and 6.5 res p e c t i v e l y . As shown on Figure 6.5, there appears to be a correspondence between the passage of the temperature through 0°C at Ryder Lake s i t e with the discon- t i n u i t i e s i n received signal l e v e l recordings at 7 GHz. Figure 6.6 shows an expanded view of Figure 6.5 around 80 minutes into the event showing d e t a i l s of t h i s correspondence. Expanded views of the d i f f e r e n t i a l temperature around the d i s c o n t i n u i t i e s shows a corresponding increase i n the rate of change of temperature at these points. Figure 6.7 shows the increase i n d i f f e r e n t i a l temperature for the fade d i s c o n t i n u i t y 80 minutes into the event and Figure 6.8 shows d i s c o n t i n u i - t i e s e a r l i e r i n the event around 30 minutes. A s i m i l a r correspondence i s seen i n the Ryder temperature and the rapid changes i n the 3.550 GHz signal as shown i n Figure 6.9. These changes show that as the 0°C isotherm moves into and out of the path there are corresponding rapid changes i n received signa l attenuation. 7 1 Figure 6.3 The 3.550 GHz and 7.496 GHz Signal Levels Versus Time P R E L I M I N A R Y B R I G H T - B A N D R E S U L T S BASED DN JANUARY 23. 1982 7ELEHETRT DfllA Figure 6.4 The Dog Mountain Transmitter Site Temperature and The 7.496 GHz Receiver Level Versus Time 7 3 Figure 6.5 The Ryder Lake Receiver Site Temperature and The 7.496 GHz Signal Reciever Level Versus Time PRELIMINARY BRIGHT-BAND RESULTS BASED ON JfiNURRY 23. 1982 TELEMETRf DflTfl jAPPRox. so MI:TLTES INTO EVENT ^ i-* 2D J'.D 4^ ?o ^ ?T TIME (MINUTES) 8 - B Figure 6.6 An Expanded View At Approximately 80 Minutes Into The Event Showing The 7.496 GHz Receiver Signal Level Versus Time 75 Figure 6.7 Ryder Lake D i f f e r e n t i a l Temperature and 7.496 GHz Receiver Signal Level Versus Time Showing The Discontinuity 80 Minutes Into The Event 76 Figure 6.8 The Ryder Lake D i f f e r e n t i a l Temperature and 7.496 GHz Receiver Signal Level Versus Time Showing Discontinuities 30 Minutes Into The Event. 77 Figure 6.9 Ryder-Lake Windspeed, Temperature, and The.3.550 GHz Reciever Signal Level Versus Time 78 Bh a 4- K- 5 tun UJ £L CD PRELIMINARY BRIGHT-BAND RESULTS BASED ON JflNURRT 23. 1982 TELEMETRY DflTfl RYDER ULW WINDSPEED 11 3.550 GHz 1 1— 1 1 1 1 1 1 T 1 D.Q 3.0 6-0 9.0 12.0 15.0 IB.a 21.0 34. D 77.0 30.0 TIME (MINUTESI Figure 6.10 An Expanded View Of The Ryder Lake Windspeed and 3.550 GHz Receiver Signal Level Versus Time Approximately 90 Minutes Into The -Event 79 Figure 6.10 shows an expanded view of the Ryder windspeed and 3.550 GHz signal versus time s t a r t i n g before the 90 minute d i s c o n t i n u i t y . The sudden reduction i n received signal l e v e l was preceded by a sudden drop i n the wind- speed. Rain information for this portion of the event was not available since the r a i n buckets were obstructed by i c e . 6.2.3 February 19, 1982, 7:30-9:00 a.m. These results were taken during the easterly passage of a storm front through the path on February 19, 1982. The presence of the 0°C isotherm dur- ing this event i s indicated by the temperature recordings for the transmitter and receiver s i t e i n Figure 6.11. Excess Attenuation Ratios were calculated for both 4 and 7 GHz and are presented i n Tables 6.4 and 6.5 according to the sample points shown i n the received signa l l e v e l and r a i n rate plots i n Figure 6.12. These results generally show that the measured attenuation during the presence of the bright band i s s i g n i f i c a n t l y greater than that due to pure r a i n . Although there i s a great v a r i a b i l i t y i n the Excess Attenuation Ratios for this event t h i s could be attributed to r a i n rate for the path being taken at only one s i t e (Agassiz) and to the turbulent nature of the storm front as i t passed through. Evidence of the turbulent make-up of th i s event i s observed i n the rapid fluctuations of the Ryder Lake temperature and windspeed plots shown i n Figure 6.11. S c i n t i l l a t i o n l i k e fading phenomenon which appeared f i r s t on the chart recordings i n section 6.1 also were observed i n t h i s event i n the 7.496 re- ceived s i g n a l l e v e l s . More observations and analysis needs to be undertaken Figure 6.11 Ryder Lake and Dog Mountain Temperatures, Ryder Lake Windspeed and The 7.496 GHz Receiver Signal Level Versus Time 81 Figure 6.12 Agassiz Rain Rate, The 7.496 GHz and 4.010 GHz Receiver Signals Versus Time Table 6.4 February 19, 1982 Results Frequency Average Average Attenuation in dB & Rain Rate Excess Sample No. (mm/hr) Meas. Rain* Atten. 4.010 1 0.6 0.6 .04 0.56 2 4.0 1.6 .20 1.40 3 11.2 2.5 .57 1.93 4 9.0 2.4 .45 1.95 5 4.0 1.0 .20 0.80 6 1.2 0.7 .06 0.64 7.495 1 0.6 1.5 0.17 1.33 2 4.0 6.0 1.36 4.64 3 11.2 8.5 4.50 4.00 4 9.0 6.5 3.50 3.00 5 4.0 3.0 1.36 1.64 6 1.2 3.7 0.36 3.31 Derived using the Laws and Parson Distribution for 0°C Table 6.5 February 19, 1982 Results Frequency Average Rain Bright-band Excess Attenuation & Attenuation Attenuation Ratio Sample No. dB/km dB/km (EAR) 4.010 1 .00103 .044 42.7 2 .0048 .097 20.2 3 .0137 .134 9.8 4 .0110 .135 12.3 5 .0048 .056 11.7 6 .00145 .044 30.3 7.496 1 .0041 .092 22.4 2 .0329 .321 9.8 3 .1110 .277 2.5 4 .0860 .208 2.4 5 .0329 .114 3.5 6 .0088 .229 26.0 82.5 before d e f i n i t e conclusions as to the cause of these s c i n t i l l a t i o n s can be determined. This data does suggest, however, that these rapid fades corre- spond to rapid changes i n temperature and that these could result i n changes to the thickness of the bright band along the path. The spikes i n the temperature plot change at rates of up to 2°C per second at each side of the fade t r a n s i t i o n as shown i n Figure 6.13. The f e a s i b i l i t y of d i f f e r e n t i a l temperature p h y s i c a l l y changing at these rates i s shown by Thompson et a l . i n t h e i r paper on atmospheric turbulence measurements [71]. In this p a r t i c u l a r event the temperature fluctuations decrease to j u s t above 0°C which would suggest that the thickness of the bright band would increase due to a reduction i n temperature gradient for these periods. Further research i s being carried out to f i n d the cause of this s c i n t i l l a t i o n phenomenon. 83 Figure 6.13 Ryder Lake D i f f e r e n t i a l Temperature and The 7.496 GHz Receiver Signal Level Versus Time 84 CHAPTER VII CONCLUSIONS AND DIRECTIONS FOR FUTURE WORK 7.1 Conclusions Previous observations using chart recordings [64,65] showed that excess attenuation at 7 GHz due to the bright band i s considerable with the magnitudes being consistent with those predicted by N i s h i t s u j i and Matsumoto for watery snow. Based on these preliminary observations, the excess attenuation r a t i o s ranged from 7 to 28 times ( i n dB) while the model for watery snow predicts an excess attenuation r a t i o of 15 at 7 GHz. The large variance between the measured values from those predicted can be attributed to several f a c t o r s ; f i r s t , the inaccuracies which can be attributed to a low density r a i n bucket network for determining r a i n rates i n turbulent events, second, deviation of the thickness of the bright band from the assumed 400 m and t h i r d , differences between the path averaged p r e c i p i t a t i o n rate from that of a p r e c i p i t a t i o n rate averaged s o l e l y within the bright band. The r e s u l t s , however, suggested that the N i s h i t s u j i and the Matsumoto model for watery snow was applicable and therefore variations between measure- ment and that predicted by theory would most l i k e l y be a t t r i b u t a b l e to the experimental methods used. The remote-telemetry-based measurement system prov i d e d a c c u r a t e c o r r e l a t i o n s between meteorological phenomenon and received signal l e v e l s , confirmed the s c i n t i l l a t i o n phenomenon superimposed on the broad band fade previously observed with the chart recorders and showed that bright band propagation was affected by the turbulent meteorological phenomenon during the 85 f i r s t phases of a storm system which became more stable as the storm decayed. Excess Attenuation Ratios consistent with theory were obtainable during the decaying phases of a storm where widespread uniform p r e c i p i t a t i o n rates were occurring. Under these conditions (unfortunately only one was operating) a single r a i n bucket near the center of the path generally provided s u f f i c i e n t information. However, when the path was influenced by a storm front the r a i n information from a single s i t e was not enough to obtain consistent r e s u l t s . The s c i n t i l l a t i o n phenomenon during fading appeared to correspond with rapid fluctuations i n temperature around 0°C but further measurements and analysis are required to draw firm conclusions regarding the physical mechanisms r e s u l t i n g i n these observations. 7.2 Directions for Future Research This thesis lays the groundwork to evaluate the proposed 8 GHz d i g i t a l radio with respect to i t s a v a i l a b i l i t y under various propagation conditions. During t h i s i n t i a l bright-band study i t has become clearer that factors which can be attributed to the bright band may also s i g n i f i c a n t l y impact the propa- gation of the 8 GHz d i g i t a l radio on c e r t a i n slant paths. For example, the rapid s c i n t i l l a t i o n s observed during deep bright band fading may a f f e c t the b i t error rate performance [5,6] of the radio. Another factor of considerable concern i s that the EAR i s expected to be 15 at 8 GHz [51] and since r a i n attenuation s t a r t s becoming a s i g n i f i c a n t factor at this frequency i t makes bright band attenuation even more important. As shown by the recordings i n Figure 6.0 under heavy widespread r a i n conditions a bright band fade can l a s t f or several hours making i t an important design v a r i a b l e . Therefore 86 to der ive maximum benef i t from the next phase i n th is research program, the d i g i t a l radio and the br ight band experiment should be run concur rent ly . Figure 7.0 gives two a l ternate system block diagrams to accomplish t h i s , the f i r s t uses the data l i n k to send the rea l time clock as data and the second opt ion uses a WWVB time recorder at each s i t e . In terms of improving the present system, the fo l lowing suggestions can be made: (a) The temperature measurements at Ryder Lake (I) should be made to provide greater r e s o l u t i o n around 0°C and be sampled at 10 Hz to re ta in information on i t s v a r i a t i o n s . (b) A s tu rd ie r anemometer and radiant heater should be i n s t a l l e d at the Dog Mountain s i t e . (c) A t ime- lapse camera should monitor the Dog Mountain transmit antenna radomes for accumulations during p r e c i p i t a t i o n events. (d) A heating system should be developed to e l iminate accumulations of snow i n the ra in buckets. (e) The code for the SCAN and EXTRACT features of DBMS needs to be implemented. ( f ) A g raph ica l rout ine could be developed to plot temperature contours on a path cross s e c t i o n . (g) A s t a t i s t i c a l rout ine needs to be incorporated i n DBMS to determine fade p r o b a b i l i t i e s from the d i s t r i b u t i o n se r ies data . Long term object ives i n the area of br ight band propagation research should i n c l u d e : 87 A detai l e d evaluation of other slant paths such as earth-space l i n k s with respect to bright band e f f e c t s and t h e i r p o t e n t i a l e f f e c t on sys- tem a v a i l a b i l i t y . The N i s h i t s u j i and Matsumoto models describing snow attenuation by snow c l a s s i f i c a t i o n should be extended to the bright band. This extension should determine attenuation for the bright band by f i r s t e s t a b l i s h i n g i t s c h a r a c t e r i s t i c snow p r o f i l e i n terms of moist, wet and watery snow and then c a l c u l a t i n g the attenuation as a function of temperature gradient (or bright band thickness) and p r e c i p i t a t i o n rate. A model needs to be developed to account for the s c i n t i l l a t i o n type which corresponded to rapid changes i n temperature. 88 PATA (5 &4PJO SIGNALS P/G/T/ll ty/?oc£Ssoe.\ &4/VP PAT* P/OfTAL \T/M£ S/e/Grr~r J&fP/O P/G / Ts4L M/CXO • Y'/eocf-ssoK WKJI/B r/MS UBC M/C&O-# • • Bs4/VP /&4P/0 Py4T>* /eyptzy^ Figure 7.0 Proposed System Configurations to Incorporate the D i g i t a l Radio Monitoring System 89 APPENDIX A AUTOMATIC GAIN CONTROL (AGC) CALIBRATIONS To obtain accurate received s i g n a l l e v e l values the AGC feedback voltage must be accurately c a l i b r a t e d . This i s achieved by i n s e r t i n g a known signal l e v e l of the correct frequency into the input of the microwave receiver and monitoring the AGC voltage output. In th i s experiment the AGC voltages were monitored at the output of the receiver s i g n a l conditioning c i r c u i t (see Appendix E) and plotted against the receiver input s i g n a l l e v e l to produce the AGC curves shown i n Figures A - l to A-5. These curves then form the basis for the look up tables and i n t e r p o l a t i o n routines used as part of the entry procedure software i n the data base management system as described i n Chapter V and Appendix K. The receiver frequencies, polarizations and associated AGC curves used i n this experiment are given i n Table A - l . TABLE A - l Receiver Frequencies Polarizations and Associated AGC Curves Receiver Frequency (MHz) Po l a r i z a t i o n V = V e r t i c a l H = Horizontal Associated AGC Curve by Figure # 3550 3790 4010 7142.0 7496.5 H V H H H A - l A-2 A-3 A-4 A-5 FIGURE A - I 3550 MHZ RECEIVER A G C CALIBRATION  RECEIVER INPUT L E V E L d B m  RECEIVER INPUT L E V E L dBm 9 5 APPENDIX B DETAILS OF THE DATA ACQUISITION SYSTEM LAYOUT Figure B-l gives a 1:250,000 topographical map showing the system layout for the UBC microwave propagation experiment including a l l the s i t e s and associated data l i n k s . These include the Dog Mountain to Ryder Lake microwave path, the outgoing high speed data l i n k to UBC and the end-links to the i n t e r - mediate s i t e s of Ruby Creek, Bear Mountain and the Agassiz Experimental Farm. A more detailed description for a l l these l i n k s i s given i n Figure B-2 to Figure B-7. Figures B-2 and B-3 provide d e t a i l e d path p r o f i l e s on 4/3 earth paper for the VHF radio l i n k s from Bear Mountain to Ryder Lake and from Ruby Creek to Ryder Lake, respectively. Table B-l presents the VHF transmission calculations for these two paths using techniques developed by Bullington [11,67] and Okumura et a l . [68]. Detailed c i r c u i t layouts, showing l e v e l s , entry points and routing, are provided i n Figures B-4 and B-5 for the l i n k s from Dog Mountain to Ryder Lake and from the Agassiz Experimental Farm to Ryder Lake, respectively. F i n a l l y , a detailed c i r c u i t and routing diagram for the Ryder Lake to UBC data l i n k i s shown i n Figure B-6 and a detailed i l l u s - t r a t i o n of the associated RS 232 interface configurations between the micro- processors and the s t a t i s t i c a l multiplex units i s given i n Figure B-7. 96 TABLE B - l VHF Radio Path Transmission Calculations 1) Locations Bear Mountain Latitude °N 49°18'25" Longitude °W 121°41'30" Elevation (Meters) 945 Antenna Height (Meters) 7 DOC C a l l Sign Azimuth (°T) Frequency (MHz) Path Length (km) Path Attenuation (dB) Shadow Loss (dB) VGK 927 Ryder Lake 49 o06 ,52• 121 o54 ,07 1 236 15 VGK 928 218°T 160.11 26.1 -104.7 0.0 Transmission Line Type RG 58 Line Loss (dB) -1.0 Connector Loss (dB) -1.0 Misc. Loss (dB) -0.5 RG 58 -2.5 -3.5 -0.5 Total Losses (dB) Antenna Gain (dBd) -113.7 9.0 +11.0 Transmitter Power (dBw) -5.2 Received Signal Level (dBw) -98.9 (16+17+18) Threshold @ 12 dB SINAD (dBw) -149.0 Fade Margin (dB) SINAD (dBw) 50.1 A v a i l a b i l i t y % Annual 99.9998 [67,68,69] Ruby Creek 49°21'15" 121°36'45" 31 10 VGK 926 Ryder Lake 49 o06 ,52• 121o54'07" 236 15 VGK 928 212°T 151.79 33.7 -102.4 26.0 RG 58 -5.0 -1.0 -0.5 RG 58 -2.5 -3.5 -0.5 -141.4 +9.0 +11.0 + 4.8 116.6 -149.0 32.4 99.989 97 FIGURE B- l PATH SYSTEM LAYOUT FOR UBC MICROWAVE PROPAGATION EXPERIMENT l_jf >-Cultus Lake Chitttark Iwtr / y?™^^p.rk\ I ' - i ^ r ^ . ^ »A PROVINCIAL • :»72 FOREST^°°nl_ i 4 9 ° 0 0 - , ~ i N1TED STATES • 122°00' OF AMERICA 650 600 Figure B-2 Path P r o f i l e : Ruby Creek to Ryder Lake DISTANCE IN KILOMETERS Figure B-3 Path P r o f i l e : Bear Mountain to Ryder Lake 99 DOG MOUNTAIN DOG MOUNTAIN MICRO- PROCESSOR V.f. DATA OUTPUT 2 .0V P - P L E V E L - l 6 d B RYDER L A K E 34A 3 4A GROUP GRP. SHELF SH. U B C DATA ON GROUP N9 2 CHANNEL N s 5 OF S I G A L A R M S Y S T E M BNC V.f. DATA INPUT 16V P -P RYDER LAKE MODEM BOX Figure B-4 C i r c u i t Layout from Dog Mountain to Ryder Lake AGASSIZ EXPERIMENTAL FARM MICRO - PROCESSOR a < Ml a I E BNC Z v.f. DATA OUTPUT 10V P - P C U S T O M E R I N T E R F A C E E X C H A N G E ROUTING RYDER BNC LAKE MODEM 0 >> BOX T " J V.f. DATA INPUT 8 V P -P Figure B-5 C i r c u i t Layout from the Agassiz Experimental Farm to Ryder Lake R Y D E R L A K E R 5 2 J 2 I N T E R F A C E S 9 C T E L R Y D E R L A K E D T I •*1 O A T A C H A N N E L S F R O M U B C < T E L E M E T R Y ) S Y S T E M ' C . I • « i H e n I Y H C H R O N O U I M U X tOI C MOMM W M r- 4 1 1 2 L O O P U C I U N I T PAP 4 It «• I—I o C X R D R O U P t C H A N N E L t V A N C O U V E R R Y D E R L A K E 14 A B R O U P t C H A N N E L I r L. C U T U WK III U B C E L E C T R I C A L E N O I N E E R I N B B U I L O I N S R O O M 4 4 B I •** I < 1 > . 1 I I . . . {-•) (•«•• » • « • • M a uec R S E » I N T E R F A C E S 4 1 1 1 L O O T B A C K U N I T w 201 C M O D E M S Y N C H R O N O U S M U > PN4I00II T O U B C O A Y A L O G D A T A C O L L E C T I O N M I C R O P R O C E S S O R t CNAMMIl. V A N C O U V E R R Y D E R L A K E 3 4 A C R O U P 2 C H A N N E L t SCHEMATIC FOR THE RYDER LAKE TO UBC DATA CIRCUIT O 101 PIN I Rx 2 Tx 3 4 5 6 7 6 20 22 25 RYDER LAKE PIN <— — • PIN DESIGNATIONS U.B.C. PIN RS 232 DATA TERMINAL EQUIPMENT (DTE) DATA COMMUNICATIONS EQUIPMENT (DCE) DCE PIN n I 2 3 4 5 6 7 8 20 22 25 DTE RYDER MICROPROCESSOR OR MODEM BOX RYDER SUPER MUX 480 UB.C. SUPER MUX 480 U.B.C. DATA LOG MICROPROCESSOR Figure B-7 The RS232C Interface f o r the Ryder Lake to UBC Data C i r c u i t 102 APPENDIX C EQUIPMENT AND SITE LAYOUTS C-l Ryder Lake This s i t e i s the data concentration node where a l l the experimental f i e l d data are c o l l e c t e d before being s t a t i s t i c a l l y multiplexed onto a telephone c i r c u i t f o r transmission to the University of B r i t i s h Columbia. The on-site data a c q u i s i t i o n system serves two main purposes: f i r s t , to c o l l e c t received signal l e v e l data from f i v e selected 4 and 7 GHz microwave channels and, second, to monitor the wind speed, wind d i r e c t i o n , temperature and r a i n rate variables at the s i t e . Figure C - l i s a photograph of the s i t e , Figure C-2 shows the equipment configuration and Figure C-3 i l l u s t r a t e s the s i t e layout. Figure C - l Ryder Lake Site Photograph ANEMOMETER HAJN tUCKET imp omecriwi KETtOlltV COMCMTIOMIM I T »»ov DC •ana ymo i m p • IKO DIHCCT. T I 4 I MMi » « C - M » i MNl. AtC - •ISO MMl. * « C • I T S O MMl. M C - 4010 MMl. A » C " T I I . H K 7 . t H 0 . 9RL 816 f U l ANTENNA MIN' DO A M TO 000 MOUNTAIN 4 VIA 37A OROUP t CHANNEL 9 (SEE FIO 0-4) TO AGASSI! 4 EXPERIMENTAL FARM ( S E E FIO 8-51 n i n r • P t i r r t a vttr RADIO HCCCIVI* IHCCIIVIII U . B . C . C A T A L O G M I C R O P R O C E S S O R ( 6 8 0 0 ) R Y D E R L A K E UBC MODEM UNIT RYDER LAKE " T I T " 73 • C - l N C — U NC * RSIS2 INTERFACE (SEE FIO » - 7 ) fc=d no VAC _ L _ OC POWER SUPPLY • TO UB.C VIA J 4 A OROUP t CHANNEL t (SEE FIOO-OI OC POWER SUPPLY RYDER LAKE SITE EQUIPMENT CONFIGURATION F I G U R E C - 2 MAR. 12,110! w.l c. n f l i I O I •tola L U I o w.ac. BAT4 LM I T I C I L U I O OC POWER SUPPLY FOR VHF RADIOS BEAR MTN. VHF RECEIVER RUBY CREEK VHF RECEIVER -METEOROLOGICAL CONDITIONING UNIT M » u mix 4 1 0 mm* uui 4«o > ASYNCRONOUS MULTIPLEXER 201C - MODEM - SYNCHRONOUS MULTIPLEXER 4112 LOOPBACK MODULE FRONT VIEW OF THE UBC EQUIPMENT BAY AT RYDER LAKE 1 VHF RECEIVE ANTENNA ANEMOMETER TELEPHONE CIRCUIT PLAN VIEW OF THE RYDER LAKE SITE RYDER LAKE SITE LAYOUT FIGURE C - S MAR 12,196?. o 105 C-2 Dog Mountain The Dog Mountain s i t e which i s the transmitter s i t e and the northern terminus of the microwave l i n k under i n v e s t i g a t i o n , has an e l e v a t i o n of 1463r. A weather s t a t i o n located there senses meteorological information and sends I t back to Vancouver v i a a spare data channel on the 51G alarm system to the Ryder Lake s i t e . At Ryder Lake t h i s information i s s t a t i s t i c a l l y multiplexed for retransmission to UBC. Access to the s i t e i s by cable car as shown i n the s i t e photograph, Figure C-4a. Figure C-4a Dog Mountain S i t e Photograph The equipment configuration i s given i n Figure C-5 and a s i t e layout (relevant to t h i s work) i s shown i n Figure C-6. 106 This s i t e experiences severe i c i n g conditions which have caused the destruction of the experiment's i n i t i a l anemometer, as shown i n Figure C-4b. To prevent t h i s destructive i c e build-up i n the future i t i s recommended that a radiant heater be i n s t a l l e d directed at the anemometer*. The weather micro- processor could be used to control the heater during i c i n g conditions by turning i t on only during a -5°C to +3°C temperature range. Figure C-4b A Photograph Showing Damage to the Anemometer Caused by Severe Icing Conditions at Dog Mountain ANEMOMETER KfTtOM- LMICAi. I J t U l r 110 VAC 1 OC POWER BUPPLV HPO PIPICTIOW » ' » » • » » U B C . WEATHERLOO MICRO PROCESSOR (BOSS) DOS MOUNTAIN VF. DATA OUTPUT I V p-p I jooJ tiit PAD • WAT «PO WU M I O 0 I 34 A OROUP I CHANNELS 0 n o NE ?N 910 LARM CHANNEL TO U.B.C. VIA RYDER LAKE U E F l O t C -t 00 •-• TO II t A I M N tTPTIM PROPOSED PROPOSEO CAMERA HEATER CONTROL CONTROL DOG MOUNTAIN SITE EQUIPMENT CONFIGURATION •'• FIGURE C - S ISSUE I FEB. 26,1981 TO 34* CHANNEL (ONI CHS) \ V/// TEMPERATURE PR06E OC POWER SUPPLY - B C TEL EOUIPMENT » U «e«TNU L M DO# MOUNTAIN r PROM METEOROLOOICAL SENSORS use. EQUIPMENT - BAY -METEOROLOOICAL INTERFACE UNIT BATTERY AREA CABLE FROM METEOROLOOICAL SENSORS THE PLAN VIEW OF DOG MOUNTAIN SITE / / / / / / / ; / / /"/ / -ANEMOMETER FRONT VIEW OF THE UBC EOUIPMENT BAY AT DOG MOUNTAIN DOG MOUNTAIN SITE LAYOUT FIGURE C - 8 FEB. 28 ,1981 o 0 0 l n 9 C-3 Agassiz Experimental Farm This site has an elevation of 15m, is 17.8 kilometers from the Ryder Lake receive end and is 200 meters off beam-center. Its primary purpose is to collect meteorological data with particular emphasis on the measurement of rainfall. This site is co-located with the experimental farm's weather station which provides a source of valuable back-up data, as well as gives information on other variables such as pressure and humidity which are not monitored in this experiment. Being situated 610m below beam elevation, melted precipitation rates can be measured using a tipping bucket rain gauge even though the freezing level may be at or below path elevation. The data thus collected are sent to Ryder Lake via a telephone circuit and from there on to UBC, using the statistical multiplex. Refer to Figure C-7 for a site photograph, Figure C-8 for the equipment configuration and Figure C-9 for the site layout. Figure C-7 Agassiz Experimental Farm Site Photograph 8 — r - < 3 ANEMOMETER TEMPERATURE WHO OmiCTIM W'WD i m p IIO VAC _ J POWER SUPPLY BNC U.at WEATHERLOQ MICRO PROCESSOR (8085) AOASSII EXPERIMENTAL SITE BNC =13 vr DATA OUTPUT l O V p - p • C TtL CUITOIttA IMUNrtCI TO U.B.C. POC— VIA RYDER LA K E I M S n « * e - i A AGASSIZ EXPERIMENTAL FARM SITE EQUIPMENT CONFIGURATION FIGURE C - 8 h-1 O j- BC T CUPHONf / OUTLET I T*»LI ro* THfl lUIIII •lr>CHII1II1T«L MM HITCOItOLOflCAL (MTKUM UTI y WALL _1 U.i.C •TIATHItLM m i n i o 0 I 1 H I M H 1 I L WMMO HETEOBOLOOICAL SIGNAL CONDITIONING UNIT FRONT VIEW OF THE UBC EOUIPMENT AT THE AGASSIZ EXPERIMENTAL FARM PLAN VIEW OF THE AGASSIZ EXPERIMENTAL FARM SITE AGASSIZ EXPERIMENTAL FARM SITE LAYOUT FIGURE C - 9 FEB. 2S.I9SI 112 C-4 Ruby Creek The Ruby Creek Site has an elevation of 31m, Is 300m off beam-center and 33.9 kilometers from the Ryder Lake receive end. The site provides for power, a tower and a shelter. It also l i e s 1158m below beam elevation, making i t well suited for use as an intermediate weather station for monitoring melted precipitation rates. The sampled data are sent to Ryder Lake via a VHF radio link and from there i t is assigned a data multiplex channel to complete the routing to UBC. For detailed information, refer to Figure C-10 for a site photograph, Figure C - l l for the site's equipment configuration and Figure C-12 for the site layout. Figure C-10 Ruby Creek Site Photograph NO CONNECTION TO ANEMOMETER Tiff IN* RAIN tUCXET TEMPERATURE ~ It ItETEORO-LORICAL •IQRAL CONDITION!* UNIT •»— . RAIN CLEAR < ^ H C WIHO Ol RECTI ON M C ^ j . NC VINO •Mtft NC, IIOVAC I OC POWER SUPPLY U3.C. W E A T H E R L O G M I C R O P R O C E S S O R ( S O B S ) R U B Y C R E E K -o 191.76 M H i G A I N 9.0 4 B * 2 I 7 . 4 * T POWER SUPPLY T O U B C V I A R Y D E R L A K E ( S E E r i o ' i C t • M l VHF RADIO TRANSMITTER t o r n TO RMC RUBY CREEK SITE EQUIPMENT CONFIGURATION «0I> IKN U K WCATHCRLOO DC POWER SUPPLY FOR V H F RADIO FRONT VIEW OF THE UBC EQUIPMENT AT THE RUBY CREEK INSTALLATION PLAN VIEW OF THE RUBY CREEK SITE RUBY CREEK SITE LAYOUT ISSUE f 115 C-5 Bear Mountain The Bear Mountain site is located at beam elevation on a mountaintop near mid-path. It has a site elevation of 945m and is situated 26.3km from Ryder Lake and 3km to the northwest side of the microwave beam. The Bear Mountain site is important for investigating the bright band region since i t allows an Intermediate temperature point to be monitored thus enabling a more accurate temperature gradient profile to be established allow- ing a more accurate determination of the bright-band thickness. In the final site selection, special consideration has been given to finding a sheltered Figure C-l3 Bear Mountain Site Photograph 116 lo c a t i o n that would minimize misleading readings due to l o c a l convection e f f e c t s . A photograph of the s i t e i s i l l u s t r a t e d i n Figure C-13. The weather data w i l l be monitored by a battery-powered data a c q u i s i t i o n system and transmitted to UBC v i a a 0.3 Watt VHF radio l i n k to Ryder Lake. The equipment configuration f o r th i s system i s shown i n Figure C-14 and the s i t e layout i n Figure C-15. C-6 University of B r i t i s h Columbia Recording Terminus The University of B r i t i s h Columbia (UBC) s i t e i s located i n Room 448 of the E l e c t r i c a l Engineering building and i s the terminus for a l l the data c o l - lected. The data which arrive v i a a telephone c i r c u i t , are demultiplexed, coded with the sampling time and condensed for storage on magnetic cassette tape. F a c i l i t i e s are provided for the re a l time viewing of the incoming data using the video terminal and the chart recorder together with the d i g i t a l to analog convertor. A photograph of the UBC terminus i s shown i n Figure C-16. The equipment configuration i s shown i n Figure C-17 and the s i t e layout i n Figure C-18. •am CIIH BNC 0 \) (00 tl MH] u 0 A I N S O I rt tH.6«T ; TO U.B.C •y RYDER LJ U.B.C. REMOTE WEATHERLOG MICRO PROCESSOR (1802) BEAR MOUNTAIN JUL. DC POWER SUPPLY (BATTERY! CAUSTIC POTASH 1000 A-MR CAPACITY BEAR MOUNTAIN SITE EQUIPMENT CONFIGURATION • ' FIGURE C-14 ISSUE I MAR IC.ISS2 SIDE VIEW OF EQUIPMENT TREE PLAN VIEW OF THE BEAR MOUNTAIN SITE FIGURE C - 1 5 •MR. 12.198 J 0 0 119 Figure C-16 University of B r i t i s h Columbia Site Photograph F R O M R Y D C R L A W A N D O T H E R _ , M E T E O R O L O O I C A L 300C* S I T E S I M l F l i t • • I , C - l , O - l , c - i , c - u a e - t l l IBM 3010 COMPUTER VIDEO TERMINAL • f K > D/A CONVERTOR i ~ M DC POWER SUPPLY C H A R T R E C O R D E R M A O N E T I C T A P E R E C O R D E R UNIVERSITY OF BRITISH COLUMBIA EOUIPMENT CONFIGURATION FIGURE C - 1 7 M A R . 12,1982 WINDOW IBM 3101 VIOCO TERMINAL /lP N» I OATA a FORMATTER. M I C R O P R O C E S S O R R A C K M l OATA PROCESSOR S T N C M U > M̂D'EM S U P E R M U X 4 8 0 S U P E R M U X 4 8 0 ^ W A L L S ] \ \ \ \ \ FRONT VIEW OF THE UBC EQUIPMENT TABLE I POWER STRIP I B M 9101 V I D E O T E R M I N A L O A CONVERTOR r t P t m c m . j^j RECORDER PROCESSORi C H A R T R E C O R D E R ROOM 448 HECTOR MCCLOUO BUILDING SUPER MUX 4*0 PLAN VIEW OF THE UBC SITE UNIVERSITY OF BRITISH COLUMBIA SITE LAYOUT FIGURE C - 18 MAR. .It, 1 9 8 2 122 APPENDIX D METEOROLOGICAL TRANSDUCERS D-l The Anemometer The anemometers used are of the propeller-vane v a r i e t y capable of measur- ing both wind speed and wind d i r e c t i o n . A photograph of an anemometer i s shown i n Figure D - l . Figure D-l A Photograph of the Anemometer To be able to monitor wind speed and wind d i r e c t i o n using the anemometer, three separate input and output signals need to be Interfaced to the u n i t , as shown i n the c i r c u i t and wiring diagram of Figure D-2. These include the potentiometer input e x c i t a t i o n voltage for azimuth, i t s output voltage and the wind speed output voltage derived from the pr o p e l l e r - d r i v e n DC generator. 123 Figure D-2 Anemometer C i r c u i t & Wiring Diagram These units have proven to work r e l i a b l y at a l l s i t e s except for Dog Mountain where severe i c i n g conditions damaged the i n i t i a l anemometer i n s t a l - l a t i o n . A radiant heater has been recommended to resolve t h i s problem, as indicated i n Appendix C-2. D-2 The Tipping-Bucket Rain Gauge The r a i n gauges used are of the tipping-bucket var i e t y and are capable of measuring point r a i n rates up to 400 mm/hr. Accurate measurement above t h i s rate i s not important due to the low p r o b a b i l i t y of such events i n t h i s area. The r a i n gauges have a c o l l e c t i n g area of 383.6 cm2 and a nominal t i p size of 12.2 grams or 12.2 cubic centimeters of water so that a t i p occurs 124 after each .318 mm of r a i n . This c a l i b r a t i o n i s done by f i r s t pouring a known quantity of water through the bucket and counting the number of t i p s to give the volume of water per t i p . Then, by d i v i d i n g the volume of water per t i p by the c o l l e c t i n g area of the bucket, the r a i n f a l l per t i p , i s c a l c u l a t e d . E l e c t r i c a l sensing i s accomplished by generating a pulse as the bucket t i p s by passing a permanent magnet, attached to the bucket's t i p p i n g arm, i n near proximity to a chassis-mounted reed switch. Rain bucket maintenance has been minimal during the l a s t year of operation, l a r g e l y due to t h e i r p l a s t i c corrosion proof construction. Figure D-3 shows a photograph of the r a i n bucket and i t s t i p p i n g assembly. Figure D-3 A Ty p i c a l Rain Bucket and Tipping Assembly. 125 D-3 The Temperature Transducer The operation of the temperature transducer is based upon the linear temperature coefficient of a semi-conductor junction when forward biased with a constant current. The forward voltage which results across the junction varies linearly with temperature and is amplified to produce a DC output volt- age of 10 millivolts per degree with separate gain circuits to provide indica- tions In degrees Centigrade or degrees Fahrenheit. A photograph of the temperature transducer appears in Figure D-4. The temperature sensor Is located on the tip of the probe. The tri-position switch allows for selection between an off position, or either the Fahrenheit or centigrade gain circuits. In this experiment the Fahrenheit gain circuit is selected in order to maintain unipolar operation into the conditioning cir- cuits over the desired temperature range of 0°F-64°F, (Appendix E). Figure D-4 Photograph of the Temperature Probe 126 C a l i b r a t i o n of the temperature transducer can be accomplished by the following one-point c a l i b r a t i o n procedure. F i r s t the probe i s immersed i n a cup of semi-melted snow (temperature 32.2°F or 0°C). Then the t r i - p o s i t i o n switch i s used to select both the Fahrenheit and Centigrade gain scales and the output voltages are noted. These voltages represent the freezing point for each scale and the difference between the two readings represents 32.2°. Thus i f the Fahrenheit scale i s used for monitoring, the lower of the two voltage readings i s 0°F and, s i m i l a r l y , i f the centigrade scale i s used the higher of the two voltage readings i s +32.2°C. (This c a l i b r a t i o n assumes that both the °C and °F gain c i r c u i t s have been accurately calibrated according to the i n s t r u c t i o n manual.) Care must be taken to ensure that the temperature probe i s i n s t a l l e d with an i s o l a t e d DC power supply since the probe loses c a l i b r a t i o n when a non-isolated source i s used due to a ground loop condition. Response Time The response time of the temperature transducer was measured to be 60 degrees Centrigrade per second. This was done by quickly immersing the temperature probe into a cup of cold water a f t e r being i n a room temperature enviroment and observing the response on a storage o s c i l l o s c o p e . 127 APPENDIX E SIGNAL CONDITIONING UNITS E-1 Meteorological Signal Conditioning Units The - e t e o r o l o g i c a l s i g n a l conditioning units provide the i n t e r f a c e between the various weather transducer outputs and the + 0-5 v o l t range analog to d i g i t a l convertor inputs. The c i r c u i t , as presented i n Figure E-2, i s op- amp derived. Adjustable potentiometers at the front edge of the printed c i r - c u i t board (see photograph i n Figure E-1) provide gain c o n t r o l adjustments f o r each of the conditioned s i g n a l s . The input/output connections f o r the unit are shown i n Figure E-3. Figure E-1 Top View Photograph of the Meteorological Signal Conditioning Unit. K> CO 129 G o G TIP 0 BKT G © CNT ® RAIN G TEMP ® TEMP o POWER G G G G G G SPARES ® ws © WD METEOROLOGICAL INTERFACE UNIT h-ACCESS HOLES TO GAIN CONTROL POTENTIOMETERS 0 ) FRONT VIEW RAIN 0 TEMP 0 WS 0 WD 0 0 0 0 0 RAIN CLEAR -12 V • 5 V + 12 V b) REAR VIEW Figure E-3 Front and Rear Views of the Meteorological Signal Conditioning Unit. 1 3 0 The set-up procedure i s best completed i n the laboratory before i n s t a l l a - t i o n and i s done through the adjustment of the gain control potentiometers. The procedure to c a l i b r a t e each meteorological variables i s as follows: i ) Rain: Connect the counter and r a i n bucket leads to the front panel inputs using 'harwin' connectors and observe the output from the rear panel using an o s c i l l o s c o p e . Connect a pulse generator into the r a i n clear port on the back panel and set i t for a several second i n t e r v a l between pulses. Now adjust the gain of the r a i n c i r c u i t u n t i l a bucket t i p pulse latches high at the output, indicated by the green LED turning on. Next, observe to see i f the pulse from the generator clears the l a t c h . If not, ease off the gain u n t i l the latch i s cleared. When both a t i p of the bucket sets the latch and a pulse from the generator resets i t , the r a i n c i r c u i t i s ready for operation, i i ) Temperature: Connect the output of the temperature probe into the front panel input of the meteorological conditioning unit using 'harwin' connectors. Ensure that the temperature probe i s powered from an i s o - lated -9.0 v o l t DC power source so that the accuracy of the c a l i b r a t i o n i s maintained. Now place the probe into an i c e water mixture and adjust the gain u n t i l 32.2°F. on the Fahrenheit scale gives an output of 2.5 v o l t s . The c i r c u i t i s now ready for operation. This procedure provides a temperature dynamic range of 0°F (0 v o l t s ) to 64.4°F (5.0 v o l t s ) . 131 i i i ) Wind D i r e c t i o n : Connect both the +5 v o l t s azimuth e x c i t e r voltage and the wind d i r e c t i o n input voltage to the input molex connector (See Figure E-2 for d e t a i l s ) , i v ) Wind Speed: Connect the windspeed output of the anemometer to the input of the molex connector (See Figure E-2 for d e t a i l s ) . Now adjust the potentiometer for a gain of 1/2.. This i s e a s i l y accomplished by using a dual trace oscilloscope where the f i r s t channel at 1 volt per d i v i s i o n monitors the input voltage and the second channel at 0.5 volt per d i v i - sion monitors the output voltage. At ground p o s i t i o n a l i g n both traces. Now apply a fan to the anemometer propeller and adjust the gain so that the two traces remain superimposed. This procedure allows for wind speeds i n excess of 100 kilometers per hour to be monitored and allows the factory c a l i b r a t i o n graph for output voltage versus wind speed to be read d i r e c t l y by simply d i v i d i n g the "oltage scale i n h a l f . The Bear Mountain Conditioning Card The c i r c u i t schematic for the Bear Mountain signal conditioning card i s presented i n Figure E-4. As shown, the c i r c u i t i s b a s i c a l l y two parts, the f i r s t being a single op-amp d i f f e r e n t i a l amplifier to condition the tempera- ture voltage and the second i s a voltage follower, S-R l a t c h to condition the bucket t i p voltages. The t o t a l current consumption i s less than 5 ma for t h i s configuration making i t well suited for t h i s a p p l i c a t i o n . 132 GAIN OUT ^2 V = R, VALUES USED R, = 2 2 K R 2 = I O O K a) TEMPERATURE CONDITIONING CIRCUIT b) RAIN CONDITIONING CIRCUIT Figure E-4 C i r c u i t Schematic for the Bear Mountain Signal Conditioning Card 133 E-2 Receiver Signal Conditioning The receiver signal conditioning unit provides an optimum input range of + 0-5 vo l t s i g n a l to the analog to d i g i t a l convertor from the 4 and 7 GHz receiver AGC outputs. The c i r c u i t schematic for one of the d i f f e r e n t i a l amp- l i f i e r gain blocks used on the receiver conditioning card i s shown i n Figure E-5. A d i f f e r e n t i a l gain block was used for each of the f i v e AGC voltages monitored and a l l f i v e gain blocks required were incorporated on one card which was mounted on the 6800 mother board. The same card was also used at Ryder Lake to condition the meteorological signals. Table E-1 provides the re s i s t o r values used to achieve the optimum gains for each receiver and meteorological signal monitored. Table E-1 The Resistor Values Used i n the D i f f e r e n t i a l Gain Block for Optimum Gain SIGNAL R l » R i + R 2,R 5 R 6 ' R 7 R 3 GAIN Q p T 3550 GHz 20K 5 OK 25K lOOKpot - .93 3790 GHz 20K 50K 25K lOOKpot - 1.26 4010 20K 50K 25K lOOKpot - 1.40 7142.0 10K 10K 50K 50Kpot -35.0 7496.2 10K 10K 50K 50Kpot -50.0 WS 10K 50K 10K lOOKpot + 0.5 WD 10K 50K 22K lOOKpot + 0.8 TEMP 50K 5 OK 50K lOOKpot + 5.0 RAIN 10K 50K 22K lOOKpot + 1.0 134 IF : R | = R 4 ; R 2 = R 5 i R6=R? Figure E-5 C i r c u i t Schematic for One of the Gain Blocks for the Receiver Signal Conditioning Card 135 Set Up Procedure Each rece iver condi t ion ing c i r c u i t i s set -up i n the same manner. F i r s t inser t a s i g n a l +10dB higher than the normal c lea r weather received s i g n a l l e v e l s in to the input of each microwave rece iver using a microwave s i g n a l generator. This provides a safe margin for overfades. At th is l e v e l , tune the gain of the rece iver cond i t ion ing unit to match the highest al lowable input voltage to the analog to d i g i t a l convertor . Af ter doing th is the rece iver s i g n a l condi t ion ing unit i s now ready to be included as part of the c a l i b r a t i o n procedure to obtain the AGC curves i n Appendix A. 136 APPENDIX F ANALOG TO DIGITAL CONVERTOR Two types of analog to d i g i t a l (A/D) convertors have been used i n th i s work. The f i r s t unit i s a 16 channel A/D with 12 b i t s resolution developed for use with the 6800 system by the Communications Research Centre, Ottawa, and i s currently being used i n the Ryder Lake microprocessor (see Appendix I ) . The second unit i s a low power consumption 16 channel A/D with 8 b i t s r e s o l u - t i o n which has been e s p e c i a l l y designed for this research, to be used i n con- junction with both the RCA 1802 and the INTEL 8085 microprocessors. The remainder of this appendix w i l l deal with this second A/D convertor. Figure F - l provides photographs of this A/D convertor viewed by i t s e l f and as an i n s t a l l e d u n i t . F - l Functional Description The second A/D convertor has the c a p a b i l i t y of addressing one of sixteen + 0-5 volt analog channels and converting the voltage appearing on the s e l e c t - ed channel to a latched hexi-decimal output with values ranging from 00 to FF. Although the 0816 A/D convertor module has the c a p a b i l i t y of 16 input chan- nels, so f a r only four conditioned meteorological outputs from the condition- ing unit have been connected. These A/D channels are assigned according to the following t a b l e : Figure F - l Photographs showing the A/D Convertor Separately and I n s t a l l e d . 138 TABLE F - l A/D Convertor Channel Assignment Table A/D Channel Meteorological Variable 3 Wind Direction 4 Wind Speed 5 Temperature 6 Rain 7 Not Defined When this A/D convertor i s used with an 8085 system, control of the chan- nel s e l e c t i o n and variable conversion i s done through the s e l e c t i o n of appro- pr i a t e software output i n s t r u c t i o n s . Figure F-2 provides a schematic of the A/D convertor board with the con- t r o l l o g i c associated with s p e c i f i c output ins t r u c t i o n s i d e n t i f i e d . Figure F- 3 provides the timing between each of the control s i g n a l s . In the design of this A/D board s p e c i a l care has been taken i n s e l e c t i n g components with low power consumption to allow d i r e c t a p p l i c a t i o n of this unit i n battery powered s i t e s such as Bear Mountain. F-2 A/D Convertor C a l i b r a t i o n Procedure C a l i b r a t i o n of the A/D convertor i s accomplished by sweeping the 0-5 V range of a selected A/D channel with a known voltage and monitoring the value of the hexidecimal output. This procedure i s s i m p l i f i e d i f the test program i n Figure F-5 i s used. It allows the A/D's hexidecimal output to be viewed d i r e c t l y on an oscilloscope by monitoring the s e r i a l output pin (SOD) of the 8085 microprocessor. Figure F-4 provides a sample oscilloscope trace of SOD using the c a l i b r a t i o n test program. R A I R c u m A/D BOARD SCHEMATIC ICI •Dean PHYSICAL LAYOUT /I 40M \ i CIRCUIT SCHEMATIC a PHYSICAL LAYOUT FOR T H E W E A T H E R L O G A N A L O G U E TO DIGITAL C O N V E R T O R FIGURE F - 2 M A R . 12.1962 140 OUT 01. 0 U T " 4 F OUT 2 F S T A R T C O N V E R S A T I O N (SO ADDRESS L A T C H E N A B L E (ALE) END OF CONVERSATION ( E O C ) JI I I i I I TYPICALLY lOQx/sec Figure F-3 Control Signal Timing Diagram for the A/D Converter RS232 OUTPUT (SOD) •12V -12V OUTPUT = 29 HEX 0 0 1 0 1 0 0 1 7 MSB 6 5 4 3 2 1 RAIN CLEAR OUTPUT •5V 0 LSB PULSES PRODUCED IN SOFTWARE BY THE "OUT IF" INSTRUCTION Figure F-4 Sample Oscilloscope Traces of the A/D Output During C a l i b r a t i o n 141 Tektronix 8000/8085 ASM V3. 1 P « 9 C 00001 00002 -00005 00004 00005 oooo: i t THIS PROGRAM READS ONE CHANNEL OF THC A/D AND OUTPUTS THE I RESULT IN C0NTIN0U3 LOOP FASHION SO THAT THE DATA CAM DE READ FROM Or : I L L C A RAIN CLEAR PULCE—IT I '".'CD 00007 00003 -©000?- 00010 00011 •O0012• I EACH PIT AND A DOUBLE PULSE IS USED TO INDICATE THE START OF THE I DATA BYTE. ON THE SCOPE THE DATA APPEARS WITH THE LEAST SICVIIFIO* -: : BIT—AS—THE-THE FIRST-BJT--AT-THE-LEFT SIDE-OF-THE DATA BYTE. - - 00013 00014 -OO015. 00016 00017 •ocuais oooo 0100 0102 01 fi-1 oooo C30001 ORG OOOH JMP MAIN -ORG—lOOH- D300 MAIN MVI A.31H OUT 00 MVI A.03H 00019 OOOl'O -0002- SIM MVI H.3FH SPHL DATA CHANNEL ON A/D IS SELECTED 00040 00041 00012 IN 02 IN 02 00043 00044 00045-0004 & 00047 000.1;: DATA BYTE IS SENT OUT IN A CONTINOUS LOOP FASHION 012A 01 7'T OEOS ? # # # # # * * # # * * * # * # * # * # * * « • # * # # # # # * * # » * * * * # * * * * # * * CC2 MVI COSH 0004? 00050 —00051- 00052 00053 C12E 0130 0131 0132 0134 D31F OF 4 7 Fi.̂ O E6C0 CUT IFH CC1 RRC MOV..D*-A— ORI 40H ANI OCOH 00054 00055 -00056 O0057 0005S 0136 0133 0139 013A 013B OOOS' -' 010C D31F 30 78 OD C23001 OUT IFH SIM DCR C JN2 CC1 «.'MP CC2 00060 00061 -OO062 00063 00064 000^5 0150 0151 0152 0154 Oir-5 0150 00 •C9 1E50 ID 025101 DELAY ORG 150H NOP -SET DL1 CC? MVI E DCR E JNZ ceo 50H 00066 00067 0153 C? RET Figure F-5 A/D C a l i b r a t i o n Program 142 APPENDIX G DIGITAL TO ANALOG CONVERTOR The d i g i t a l to analog (D/A) convertor has been used i n the f i r s t phase of this experiment to generate chart recordings of the variables sampled by the data a c q u i s i t i o n system and to v e r i f y the accuracy of the res u l t s processed by the data base management system (Chapter V). The c i r c u i t schematic for the D/A unit and i t s interface to the UBC 6800 microprocessor i s presented i n Figure G-l. In the f i r s t phase of this experiment the D/A was used i n conjunction with the cassette recorder. This was done by f i r s t using the recorder to store the time series data as i t arrived at UBC from one selected RS 232 data channel. The data thus taken was then read back from the cassette recorder into the UBC 6800 microprocessor which selected a p a r t i c u l a r variable from the time series data to be outputted through the D/A. This s e l e c t i o n process i s e a s i l y accomplished since each variable a r r i v i n g on the RS 232 port i s assigned a s p e c i f i c p o s ition with respect to the sampling-interval synchro- n i z a t i o n byte. The program for this s e l e c t i o n i s given i n Figure G-2. TYPE RS232 CONNECTOR TO D/A PORT ON MICRO PROCESSOR MSB Bl 7 Bz 6 6 B 3 7 5 B4 8 4 Bs 9 3 B 6 10 2 B7 11 | LSB B8 12 9 _ 1 r DAC-08 3 16 13 Aj>F r X H .01/JF Eo = I F S " R L TO CHART RECORDER H r -IOV. +IOV. Figure G-l C i r c u i t Schematic f o r the D/A Converter T H I S PRnpftAM I S USED TO SF|_ FCT TTM F — S F R TFS ! AS I T A R R I V E S AT UBC FROM THE DATA L I N K j A V A R I A B L E R E L A T I V E TO A SYNCHRONIZATION i BYTE ISL.SELEC.TEEI_FCR_ OUTPUT. TO.. JHE_D7.fi ! AND THE A P P R O P I A T E V A R I A B L E I S CHOSEN BY '. E D I T I N G THE COMMENT STATEMENTS j ORG OEOOOH I VARPTR EQU O O O l ?VARPTR EQU 0002 i 1 ?VARPTR EQU 0003 VARPTR ?VARPT EQU ^ EQU 0004 0005 7 ACTIVATED FOR RAIN OR RX#4 STK'PTR EQU 0AO50H PIACRA EQU 0801 I K • • PIADRA EQU OSO1 OH : PIA REGISTERS CTR EQU CLR 0A040H PIACRA LDA A #OFFK CLEAR PIA CONTOl RESIST ER STA A PIADRA SET PIA AS OUTPUT LDA A #04H ; NON INTERRUPT PORT STA A PIACRA LDA A #03H 7 RESET ACIA STA A OSO1 EH LDA A #015H STA A OSO1 EH ; COMMAND REGISTER SET UP LDS #STKPTR 5 STACK POINTER LOOP LDA A OSO1 EH LOAD STATUS FROM PORT 7 LSR A BCS DTOA RDRF YES GET BYTE •JMP LOOP DTOA LDA B 0S01FH 7 LOAD CMP B ttOFFH ; IS IT SYNCH BEQ ZERO YES- RESET COUNTER ! LDA A CTR CMP A #VARPTR IS THIS THE VARIABLE BEQ OUTPUT Y E S : SEND OUT D/A I NC CTR •JMP LOOP NO: INPUT NEXT VARIABLE OUTPUT STA J L PIADRA 5 SEND OUT D/A I NC CTR JMP LOOP 7FRi"! i":.' R CTR RESET COUNTFR I NC CTR JMP LOOP LOOK FOR NEXT BYTE „ „. END _ Figure G-2 L i s t i n g of the Program to Provide Chart Recordings from the Receiver Data Using the D/A 145 APPENDIX H MODEM UNITS H-l Modem Transmit Units A modem transmit unit i s included i n each of the Dog Mountain, Ruby Creek and Agassiz Experimental Farm Weatherlog Microprocessors. Each unit takes a ±12 v o l t RS 232 compatible 110 bps s e r i a l data stream and encodes t h i s to output a voice frequency FSK modulated s i g n a l . The modulated s i g n a l i s then carried by way of eith e r a VHF or a telephone communications channel to the modem receivers at the Ryder Lake S i t e . The receive modems are described i n section H-2. Figure H-l Photograph of an I n t a l l e d Modem Transmit Unit 146 The centre frequencies for the modems that were available i n this project are given i n Table H-l as follows: Table H-l Modem Centre Frequency Assignments Frequency (Hz) Code Links Used 480 DA 720 DB Dog Mountain 960 DC Agassiz Experimental Farm^Bear Mountain 1200 DD Ruby Creek 1440 DE Figure H-l shows a picture of a t y p i c a l modem transmit unit as i n s t a l l e d i n a Weatherlog Microprocessor and Figure H-2 gives the interface schematic between the modem transmit unit and the microprocessor. H-2 Modem Receive Units A l l four modem receiver units are located at the Ryder Lake Site (see Appendix C) and have been integrated into one 19" rack mounted unit known as the "UBC Modem Unit". Each modem receiver inputs a voice frequency FSK modu- lated si g n a l and decodes i t into a 110 bps RS 232 compatible output to d u p l i - cate the input of the transmit unit (see Section H-l). The RS 232 output from each RS 232 unit i s then relayed onto UBC for storage v i a separate c h a n n e l on the s t a t i s t i c a l multiplex. The physical layout of the "UBC Receiver Modem Unit" depicting f r o n t , back and top views i s shown In Figure H-3 and a schematic of a t y p i c a l i n t e r - face between a modem receiver unit and the RS 232 output connections i s given i n Figure H-4. 147 MODEM TRANSMIT UNIT A O B e o 0 * E e F • H O i J o KO L O MO N O + 12 - 12 INDEX VF OUT GND. RT S TRANSMITTED DATA HALF DUPLEX HUE CTS DSR INTERLOCK LOCAL COPY 12 PIN MOLEX CONNECTOR (RED) (GRAY) (ORANGE) (BLACK) (WHITE) (YELLOW) (BLUE) (BROWN) (GREEN) © (2) 0 © © (2) 0 © © 0 0 © © © © 0 © © © 0 0 © + 12 - 1 2 POWER SUPPLY ,BNC 1 N.C. " SERIAL DATA IN N.C. + 12 • +12 N.C. N.C. TERMINAL - ± ? STRIP Figure H-2 Interface Schematic f or a Weather Log Modem Transmit Unit in u i PORTS DOB MOUNTAIN RECEIVER MOOCH CARO RUBY CRCCK RECEIVER MCOtM CARO TERMINAL STRIP S 0 9 9 ® 0 o e s a e s S 0 0 s e 0 0 e •CAR MOUNTAIN MOOCH RECEIVER CARO DC POWER SUPPLY AGASSI! EXPERIMENTAL FARM RECEIVER MODEM CARD DUMMY RESET SWITCH POWER LIGHT SWITCH TOP VIEW SHOWING INTERIOR LAYOUT OF THE MODEM UNIT | ~ ) U B C M O D E M U N I T ^ © RESET O FRONT VIEW VF INPUTS r © © © © AGASSIl BEAR MTN. RUBY CK. 000 MTN J RS 232 OUTPUTS REAR VIEW PHYSICAL DRAWING OF THE RYDER LAKE . i RECEIVER UNIT SHOWING TOP, FRONT 8 REAR VIEWS FIGURE H - S MAR 12.1912 CO 149 Y M O D E M R E C E I V E R U N I T O o o o o o o o o o o o + 12V. - I 2 V VF I N P U T GND NC RCV LOOP (-I2V1I R E C E I V E D DATA RCV LINE SIG DET NC REMOTE RCV DISABLE LOCAL COPY INPUT NC NC NC " \ T O S P O W E R - ) S U P P L Y B N C < 2 0 GND' GND RTS CTS DTR Tx F E M A L E RS232 C O N N E C T O R Figure H-4 Interface Schematic for One of the Modem Receiver Units 150 APPENDIX I MICROPROCESSOR UNITS 1-1 The UBC Microprocessors i ) General Description The two UBC microprocessors are both Motorola 6800 based units and are used f o r the purpose of time c o r r e l a t i n g the data as i t arrives at UBC from the sampling processors along the path. The data formatter unit (uP#l) c o l - l e c t s the incoming data, constructs the time series queues and outputs the results each second to the data processor unit (yP#2). The data processor unit then reduces the data to manageable lev e l s by constructing hourly d i s t r i - butions and choosing selected time series i n t e r v a l s for storage onto a 4.5 megabyte capacity cassette recorder. The software routines to do this are discussed i n Appendix J. Two methods have been employed to prevue and test the incoming data stream. The method currently used takes the time series data outputted from the data formatter (uP#l) and resends i t using the data processor (uP//2) to a video monitor. A photograph of the video display and discussion of this method i s given i n Chapter IV. A second method was employed i n the f i r s t phases of the system integration by reading selected variables from the a r r i v - ing data streams and outputting these through a di g i t a l - t o - a n a l o g convertor, as described i n Appendix G. The physical layouts for the UBC microprocessors are shown i n Figure 1-1 and 1-2 for the data formatter and data processor respectively. These draw- ings show the rear termination assignments, the front panel display and the WK tn dew tn at »- < a *t< CD O >" K tL>- Out DO U 3 K O OCO I LI I I o I v 1/0 S L O T S MPU ( WITH EPROM) R E 0 U L A T 0 R jBOARD DISPLAY BOARD S 8 0 0 MOTHER BOARD TOP VIEW POWER SWITCH IIOVA P C V ~ RUBY AGASSIZ SPARE ' • • C D O 2A SA OO FUSES . ( = • C Z D 1— I I — 1 OUT DOG BEAR RYD. SWT. BUG REAR VIEW • UT M A . RCV. o o o o o o g FRONT VIEW UBC DATA LOG © PROSRAM RE a 3 PHYSICAL DRAWING OF THE UBC DATA FORMATTER (uP N*2) MICROPROCESSORj SHOWING FRONT,TOP AND REAR VIEWS FIGURE l-l MARCH I t . l S S Z (—1 Ln h-1 < a: - £ < F 1° _• .> K Q . Q a. Til K m ta. O O o o O ID <D CD CO O t «D O O o Q O o CD « CO CD \ v — — I/O SLOTS M P U ( W I T H E P R O M ) TOP VIEW •rt'mt- na O C . P O W E R C O N N E C T O R F U S E S TT] +} +12 - 1 2 ii] o o o P R O C E S S O R D I G I T A L I 1 'î 'A- V I D E O T E R M I N A L P O R T S | ^ T A P E U N I T REAR VIEW U B C NI ! O A T A P R O C E S S O R R Y D E R R E S E T R E S E T P 3 <= FRONT VIEW PHYSICAL DRAWING OF THE UBC OATA PROCESSINC tyiP N« 2 ) MICROPROCESSOR SHOWING FRONT.TOP ANO REAR VIEWS - FIGURE 1-2 I S S U E I M A R C H 1 2 , 1 9 6 2 a) The Data Formatter (uP#l) Figure 1-3 Photographs Showing the I n t e r i o r Layout of the Two UBC Microprocessors 154 processor mother board layouts. A photograph of both microprocessors i s given i n Figure 1-3 i l l u s t r a t i n g t h e i r i n t e r i o r layouts. An i n t e g r a l part of the UBC unit are the ACIA cards which provide the communications interface between the s e r i a l RS 232 input/output ports and the p a r a l l e l data bus of the microprocessors. Each ACIA card provides an i n t e r - face to two RS 232 ports according to the assignments shown i n Table 1-1 and 1-2 for uP 1 and 2. Its c i r c u i t schematic and physical layout are given i n Figure 1-4. Table 1-1 I/O Port Address Assignments for the Data Formatter Unit yP//l I/O PORT it PORT ADDRESS FUNCTION ASSIGNMENT 0 8000 8001 8002 8003 Not assigned 8004 PIA I/O Reg. 8005 DDR 8006 PIA I/O Reg. 8007 DDR Terminal Port PIA 8008 8009 800A 800B Not assigned 800C 800D 800E 800F 8010 8011 8012 8013 ACIA CMD ACIA I/O Reg. ACIA CMD ACIA I/O Reg. Not assigned Spare 1/0 Port Ryder Lake Meteorological Table 1-1 cont'd. 8014 ACIA CMD Reg. 8015 ACIA I/O Reg. 8016 ACIA CMD Reg. 8017 ACIA I/O Reg. 8018 ACIA CMD Reg. 8019 ACIA I/O Reg. 801A ACIA CMD Reg. 80IB ACIA I/O Reg. 80IC ACIA CMD Reg. 801D ACIA I/O Reg. 80IE ACIA CMD Reg. 80IF ACIA I/O Reg. Agassiz Experimental Farm Bear Mountain Ruby Creek Dog Mountain Tape Unit RS232 Output Port Receiver Channel from Ryder Lake Table 1-2 I/O Port Address Assignments for the Data Processor Unit uP#2 PORT ADDRESS FUNCTION 8018 ACIA CMD Reg. 8019 ACIA I/O Reg. 801A ACIA CMD Reg. 80IB ACIA I/O Reg. 80IC ACIA CMD Reg. 801D ACIA I/O Reg. 801E ACIA CMD Reg. 80IF ACIA I/O Reg. ASSIGNMENT Output Port to Video Screen and Tape Unit Receive from uP#2 Future D i g i t a l I/O Ports B A U D R A T E S E L E C T I O N J U M P E R S OUTPUT CONNECTORS « 3 NCRttBXaCTSr TXtTXiRTS GND M O L E X C O N N E C T O R T O 6800 M O T H E R B O A R D J tt ii i4 it >*• \fi ii io 9 i r -mrt. | 4CI.4 USO-J , IJ H •*-tJa'- sSSjl lis DATA B U S ti *CM8» <TX) j T t r t i j j h 1 r n . * s 5 S U 5 5 i IH 13 H is /* ir im HUHIIDM »sv REG. D A T A B U S I/O S E L E C T RESET ! ' IIO 300 6 0 0 1200 9600 » 8 V R/W DT 0 6 D5 04 P' D2 DI DO RSI RS2 IRO NMI INDEX GND tl2V -I2V NC NC I N T E R F A C E C O N N E C T O R T O 6 8 0 0 M O T H E R B O A R D CIRCUIT SCHEMATIC ASYNCHRONOUS INTERFACE CARD 7BI54 6 8 S 0 - 2 I I •TO S E L E C T O P T I O N S P I N S M U S T BE J U M P E R E D | _ C H A N 2 , I I 0 B A N D J C H I , IIO t _ C H A N 2 ' 3 0 0 - C H I . 3 0 0 : H A N 2 , 6 0 0 . - C H I , 6 0 0 j — C H A N 2 , 1 2 0 0 - C H I , 1 2 0 0 IH A N 2 , 9 6 0 0 - C H I , 8 6 0 0 I N C — C T S : E X T . C O N T R O L CTS". A L W A Y S v E N A B L E D \ O P T I O N S E L E C T I O N C O N N E C T O R • 8 V N C C H I R X C H 2 R X C T S N C C H I T X C H 2 T X R T S GND M O L E X ( F ) > O U T P U T C O N N E C T O R TORS 2 3 2 P O R T S I/O CONNECTIONS PHYSICAL LAYOUTS ASYNCHRONOUS INTERFACE CARD CIRCUIT SCHEMATIC A N D PHYSICAL LAYOUT OF T H E ASYNCHRONOUS INTERFACE (ACIA) CARD F I G U R E 1-4 ISSUE I M A R 12 , 1 9 B 2 U l 157 Specifications a) MPU board • modified to produce data rates of 110, 300, 600, 1200 and 9600 bps. (uP//l). • unmodified i n uP#2 to give data rates of 110, 300, 600, 1200 and 2400 • i f the SWTBUG monitor i s to be used switch off both "PROM" dip switches and switch on the "SWT" and "MONITOR" dip switches. • to use a program i n the EPROM, switch on the "LO PROM" or the "HI PROM" dip switch and turn off the "SWT" and "MONITOR" dip switches. The EPROM program then starts i n location E000 1 & of the memory space with the interrupt vectors being assigned the following addresses. Table 1-3 6800 Interrupt Vectors Location Type of Vector E7F8 E7FA E7FC E7FE Interrupt Request (IRQ) Non Maskable Interrupt (NMI) Software Interrupt (SWI) Restart b) ACTA board • The boards must be strapped according to Figure 1-4 to determine t h e i r data rates. 158 c) Regulator board Input Voltage: ±24V Output Voltages: +12V -12V +14.6V -14.6V UD1 (uP//l only) UD2 (uP//l only) d) Total AC power required 500ma at 110V. A.C. 1-2 The Ryder Lake Microprocessor Unit The Ryder Lake Microprocessor unit i s based on the Motorola 6800. Its purpose i s to sample both the received signal l e v e l s and the meteorological information from this s i t e and send i t to UBC v i a two separate data channels. Every 1/10 of a second the received signal l e v e l s are sampled and on every tenth sampling i n t e r v a l ( i . e . each second) the weather information i s also sampled and sent. The analog-to-digital convertor i n this unit i s able to resolve to 12 b i t s which i s more than required. Therefore, each sample i s f i r s t reduced by s t r i p p i n g the four least s i g n i f i c a n t b i t s before the 8 b i t samples are output- ted. The channel assignments for the analog-to-digital convertor are provided i n Table 1-4, as follows: 159 Table 1-4 Analog to D i g i t a l (A/D) Convertor Channel Assignments A/D Channel Channel Assignment F Unassigned E Unassigned D Rain C Temperature B Wind Speed A Unassigned 9 Wind Direction 8 Unassigned 7 Unassigned 6 Unassigned 5 Unassigned 4 7496 GHz Rx 3 7142 GHz Rx 2 4010 GHz Rx 1 3790 GHz Rx 0 3550 GHz Rx • Figure 1-5 provides a drawing showing the hardware assignment s l o t s for the CPU, the ACIA card and the an a l o g - t o - d i g i t a l convertor. Table 1-5 pro- vides the I/O port address assignments for the Ryder Lake Unit, as follows: 5 J! 5°si « s 9 S K o o O F t CO u. 5 m o « 1 o m | § i s 1 o CD o CO 1 o 1 « o i u Q 1 o 1 » 1 CO 1 u « o « 5 • s • 8 5 CD A / D BOARD | 8 t ; » - 8 8 2 3 ) METEOROLOGICAL CONDITIONING CARD RECEIVE SIGNAL CONDITIONING CARD MPU BOARD (WITH E PROM I TOP VIEW WEATNCR CHANNELS RECEIVER CHANNELS G « O 8 & b M r ^ i t i C o o o o vie L H SPEED * K M T L 4 « Q-I2V. © PORT OC POWER OUTPUTS REAR VIEW U B C DATA LOO • RESIT O c. MO 1200 o o o n a MET (CV R Y D E R L A K E . ft POWER m FRONT VIEW PHYSICAL 0RAWING OF THE RYDER LAKE MICROPROCES- SOR UNIT SHOWING FRONT, TOP AND REAR VIEWS FIGURE X - S (MARCH 12 ,1982 o 161 Table 1-5 I/O Port Address Assignments for the Ryder Lake Unit I/O PORT # PORT ADDRESS FUNCTION ASSIGNMENT 8008 ACIA CMD Reg. 8009 ACIA I/O Reg. 80OA ACIA CMD Reg. 800B ACIA I/O Reg. High speed Receiver Data Low speed Meteorological Data 8018 to 801B DC Power Supply Interface A l l other I/O port addresses are unassigned. 1-3 The Weatherlog Microprocessor Units The weatherlog microprocessor units used at Dog Mountain, Ruby Creek and the Agassiz Experimental Farm are based on the INTEL 8085. Their purpose i s to sample the meteorological variables of wind speed, wind d i r e c t i o n , tempera- ture and r a i n at one second i n t e r v a l s . The inputs to the microprocessor's A/D channels are 0-5 volts which are provided at the output of the meteorological signal conditioning unit (see Appendix E). The weatherlog microprocessor incorporates a low speed frequency s h i f t keyed modem between the RS 232 output of the 8085 i n t e r n a l processor to the voice frequency 600 ohm unbalanced out- put of the weatherlog. The FSK output thus derived i s then applied to the corresponding channel back to Ryder Lake. From the Ruby Creek location t h i s i s v i a VHF radio, from Dog Mountain t h i s i s v i a the 37A message c i r c u i t on the A/D CONVERTOR j , h i MOOCH TRANSMIT CARD [ A / 0 TO AO»a I N T E R F A C E | MOOIM I N T E R F A C E | POWER INTERFACE r-i-ri •taHnninnnniBiiii_ X N T I L S I C R O / M •ORt C O M P U T I R • O A R D TOP VIEW MAIN - TERMINAL STRIP © • ' « WIND SPEED © WIND DIRECTION o IIO VAC ©•. O-.t VOLTAOC OUTPUTS o MOOIM OUTPUT © RAIN o RAIN CLEAR o TEMPERATURE W P U S I REAR VIEW L U B C WEATHER LOO © R E S E T DOG MOUNTAIN 3 5 9 I T E N A M E ' FRONT VIEW PHYSICAL DRAWING OF THE WEATHER LOG MICRO- PROCESSOR SHOWING FRONT, TOP AND REAR VIEWS F I G U R E 1-6 MARCH IS , 1981 163 7 GHz radio and from the Agassiz Experimental Farm t h i s i s v i a a telephone l i n k . A drawing i n d i c a t i n g the p o s i t i o n i n g w i t h i n the weatherlog unit of the 8085 computer board, the A/D convertor and the modem transmit card i s given i n Figure 1-6. A photograph of t h i s i n t e r i o r layout i s shown i n Figure 1-7. Figure 1-7 Photograph showing the I n t e r i o r Layout of a Typical UBC Weatherlog Microprocessor Unit. 1-4 The Bear Mountain Microprocessor Unit The purpose of the Bear Mountain Microprocessor i s to sample the meteoro- l o g i c a l variables of temperature and r a i n once per second and output the data onto the radio l i n k to Ryder Lake. 164 In designing the microprocessor unit for th i s s i t e , s p e c i a l care was taken to minimize the power consumption and to choose a technology which could withstand large temperature variations (±40°C). CMOS technology was selected for the microprocessor, the A/D and the signal conditioning unit. The micro- processor i s an RCA 1802 and the c i r c u i t s for the A/D and signal conditioning units are described i n Appendices F and E respectively. The t o t a l power con- sumption of the CMOS elec t r o n i c s was 70 ma. The radio used i s a hand-held unit from Motorola s p e c i a l l y designed for low power consumption ap p l i c a t i o n s . Optimization of the radio's power con- sumption was achieved through the use of a high gain transmitting antenna and eliminating the power consumption of the radio's f i n a l transmitter stage, thus reducing the RF output power from 1.5 watts to 300 mwatts and the radio's current draw to 225 ma. The expected operational l i f e - t i m e for the Bear Mountain s i t e based on 2000 A-HR caustic potash c e l l s i s therefore 1.01 years for the radio battery and 3.23 years for the elec t r o n i c s battery. It i s recommended that battery replacement i s done by helicopter since the road access i s rugged (four wheel drive only) which could damage the c e l l s . A drawing of the equipment configuration showing the microprocessor, the radio, the A/D and the signal conditioning unit i s given i n Figure 1-8 and a photograph i n 1-9. £91 166 Figure 1-9 Photograph showing the I n t e r i o r Layout of the Bear Mountain Microprocessor Unit 1-5 The NOVA 840 Minicomputer The purpose of the NOVA 840 minicomputer i s to take the data recorded on the cassette tapes and then transfer these data i n s e r i a l fashion to IBM f o r - matted 800 bpi magnetic tape. Figure 1-10 i l l u s t r a t e s the equipment arrange- ment needed to transfe r the data. In order to enter data on the NOVA, an RS 232 to current loop i n t e r f a c e was constructed as the NOVA had no RS 232 input ports. The RS 232 to current loop interface schematic i s given i n Figure I—11. 167 IO0 4.5 MEGA BYTE CASSETTE TAPE COLUMBIA RS232 DATA 300 D TO CASSETTE 1 1 CURRENT RS232 LOOP TAPE UNIT INTERFACE | 1 NOVA 1 1 CURFcENT 840 LOOP 800 bpi MAGNETIC TAPE Figure 1-10 Equipment Configuration to Transfer Data from the Cassette Tape Drive to the Nova 840 Magnetic Tape Drive. 6 168 ro /vow 64o TO ojsssrrr *?S 232 l£l/£LS Figure 1-11 C i r c u i t Schematic of the RS-232C to Current Loop Interface 169 APPENDIX J MICROPROCESSOR SOFTWARE J - l The UBC Microprocessors i ) Functional Description The main function of the UBC 6800 microprocessor software i n the data formatter (uP//l) and the data processor (yP#2) i s to time-correlate a l l the f i e l d data as these arrives on the data l i n k , output the data for r e a l time viewing on a video monitor, compress i t into s t a t i s t i c a l d i s t r i b u t i o n s , select time series segments for storage and f i n a l l y store the data on magnetic tape using suitable formats. Due to timing constraints and the complexity of i n - corporating a l l these tasks under the control of a single CPU, these tasks were d i s t r i b u t e d between two processors. The f i r s t processor, the data f o r - matter or uP//l, has been assigned the tasks of inputting the a r r i v i n g f i e l d data, coding t h i s data to re a l time, formatting i t into buffers and outputting the formatted data once per second to the second CPU. The second processor, the data processor or uP//2 has been assigned the tasks of outputting the data for r e a l time viewing on a video monitor, generating s t a t i s t i c a l d i s t r i b u t i o n s from the data, choosing time series segments and storing these records onto a magnetic cassette recorder i n a recoverable format. The interfaces between both UBC microprocessors, from the s t a t i s t i c a l multiplex and uP#l, from both microprocessors to the video terminal and from uP#2 to the cassette recorder are a l l RS232C. The input/output ports are a l l configured i n the software. 170 The program flow chart for the data formatter (yP#l) i s given i n F i g . J - l a , a diagram of i t s buffer memory organization i s shown i n Figure J - l b and the program flow chart for the data processor (yP#2) i s presented i n F i g . J-2. i i ) Input/Output Software Design Sp e c i f i c a t i o n s I. Received Signal Data The signal amplitude data arrives at the input of the data formatter (uP//].) i n r o t a t i o n a l order at one-tenth of a second i n t e r v a l s s t a r t i n g from the lowest frequency receiver. A synchronizing byte (FF) i s received a f t e r the highest frequency receiver sample arrives and i s used to update the software clock on the basis of 10 incoming synch bytes equalling 1 second. After each second the received signal data i s dumped to the data processor (yP#2). The data processor checks the incoming l e v e l s for multipath and fading by determining i f they exceed a s p e c i f i e d range. If this i s the case, a time series dump i s i n i t i a t e d . The data processor f i n i s h e s by taking each byte of receiver signal data to update an hourly d i s t r i b u t i o n buffer, to store i t i n a rotating time series queue and to send i t for viewing to a video monitor. I I . Meteorological Data Each second,.four successive bytes arr i v e on the f i v e input meteoro- l o g i c a l channels, and immediately following t h e i r a r r i v a l a synchronizing byte i s sent. Their order of a r r i v a l i s wind d i r e c t i o n , wind speed, temperature and r a i n f a l l . As each of these samples i s received, t h e i r p o s i t i o n i n the data formatter unit's (uP#l) input buffers are updated with the new values and before they are outputted to the data processor | » A C I A * • BUFFER PO i NT E ft [ • CL C BUFFERS | « BIT FIABB 10 99 P O L L I K » U T AMD OUTPL/T P O U T a «C POL BHD POL 0 0 8 P O L HUB POL m c P O L IND POL • CII POL ASA POL M C POL • MO P O L WTO P O L -*® — 0 -K£> -KiD -*® -MD -KD -KD -KD -KD _-KD ^ PCVW ) SCT DATA*« I 1 BND POL ^ BEl SVNCH FLAB •CT BFLAB BIT BUFPtn ADDPEtS EQUAL TO DUMP AOON, fOP n»o »/W PROGRAM FLOW CHART FOR uP N« I,THE ue: DATA FORMATTER MICRO PROCESSOR UNIT F I G U R E J - l o M A R C H ti , JeJ| BUFFER Ns-I BUFFER N g l 2 BUFFER 3 Figure J - l b Data Formatter (yP#l) Buffer Memory Organization INPUT DATA _rROM_«_P N t " I OUTPUT DATA TO VIDEO DISPLAY BESET TIME __SEHIES F L A O SET TIME SERIES DUMP F L A G BEGIN T1 ME SERIES DUMP . 1 r R E S E T T t M E S E R I E S F L A O S E T DISTRIBUTION DUMP F LA f t START O l S T R l B U T T o i T DUMP . 1 r UPDATE ACIA 2-« T S_ I GET MINUTES « T L A S T COUNT •12 R E S E T E V E N T F L A G ™SET TIME S E R I E S WAIT F L A O COPT TIME S E R I E S Q U E U E r I SIT HOUR F U t ^ MAIN ) PROGRAM FLOW CHART FOR uP N*2 THE UBC DATA PROCESSOR MICRO PROCESSOR UNIT FIGURE J - 2 MARCH 121ISS2 174 (yP//2). The data processor then takes each byte of meteorological data updating i t s hourly d i s t r i b u t i o n buffer, storing i t i n a rotating time series queue and outputting i t for viewing to a video monitor. I I I . Headers and T r a i l e r s Every second the time series queue block i s sent by the data formatter (uP#l) after being terminated by two "FF" t r a i l e r markers. Immediately following this a header for a new time series queue block i s i n i t i a l i z e d , comprise^ of data bytes to i d e n t i f y record type, month, day, hour, minute and second. IV. C r i t e r i a to Dump the D i s t r i b u t i o n Buffer Every hour the buffer containing the d i s t r i b u t i o n data i n the data processor (uP//2) i s dumped to the magnetic cassette recorder unless a time series dump i s i n progress. For this s p e c i a l case, the dump of the d i s t r i b u t i o n buffer waits u n t i l the time series queue dump i s completed before t r a n s f e r r i n g the d i s t r i b u t i o n data. The d i s t r i b u t i o n buffer i s comprised of f i v e types of data (wind d i r e c t i o n , wind speed, temperature, r a i n f a l l and receiver amplitude) with f i v e single byte d i s t r i b u t i o n s for each meteorological variable type and f i v e double byte d i s t r i b u t i o n s for each receiver amplitude. Each meteorological d i s t r i b u t i o n has 4 0 1 6 = 6 4 1 Q double byte bins and each receiver amplitude d i s t r i b u t i o n has 128 double byte bins to give the following t o t a l memory required for one d i s t r i b u t i o n buffer: 175 5 x [7 + 4 x 128 + 256 + 3] = 3890 bytes This includes a header of 7 bytes and a t r a i l e r of 3 bytes for each variable type. For two d i s t r i b u t i o n buffers twice t h i s number of bytes i s required to give a t o t a l processor buffer requirement of 7780 bytes. Therefore, at 9 6 0 0 bps the hourly dump w i l l take 3.2 seconds. V. C r i t e r i a to Dump the Time Series Data Whenever an event i s detected the time series queue i s dumped from the buffer i n the data processor (uP//2) to the cassette recorder unless a d i s t r i b u t i o n dump i s i n progress. In th i s case the time queue i s trans- ferred into an output buffer to await completion of the d i s t r i b u t i o n dump. The time series queue (TSQ) i s comprised of: 12 x [7 header + 5x4 meteorological + 1 0 x 5 receiver + , 1 event + 2 t r a i l e r ] = 960 bytes At 9600 bps this w i l l take a minimum of 1.0 seconds to output for storage. The receiver event f l a g i s tested i n the MAIN program. If i t i s found to be set, the TSQ dump i s i n i t i a l i z e d and the TSQ i s copied to an output buffer to f i r s t allow completion of other I/O i n progress. When a propagation event has been detected, the time series dump f l a g over the next 12 seconds i s disabled so that a dump i s not being requested every tenth of a second during the duration of the event. Another consideration i s that a flagged event w i l l not, i n general, occur conveniently at the end of an i n t e g r a l second which means when making, the TSQ copy to the output buffer t y p i c a l l y only 11 complete seconds of data would be transferred. The twelfth second block of data 176 would normally be incomplete and would consist on ,the average of f i v e one-tenth of a second receiver sample sets and an incomplete meteorologi- c a l set. The buffer must therefore be designed to hold 13 seconds to, ensure a twelve second record. The r e s u l t i n g TSQ i s given i n Figure J-3, as follows: TSQ POINTER Figure J-3 Diagram Showing the Structure of the Time Series Queue (TSQ) The TSQ pointer i s used to f i n d the f i r s t block for dumping and the next block for f i l l i n g . When the event f l a g i s set, the TSQ s t a r t i n g from the TSQ pointer i s dumped. The dump pointer cycles around from the 177 high address to the low address and then upwards u n t i l the most recently completed block i s encountered. VI. Storage Requirements The question arises as to how much data w i l l be generated for s t o r - age. There are b a s i c a l l y two types of data s e r i e s ; the f i r s t being d i s - t r i b u t i o n data recorded at 3890 bytes per hour and the second being TSQ data with a maximum rate of 288,000 bytes per hour but more t y p i c a l l y 14,400 bytes per hour at an anticipated event p r o b a b i l i t y of 0.05. Thus the t o t a l number of bytes expected to be recorded hourly i s 18,290 bytes. At this rate the 4.5 mega byte magnetic cassette cartridges can be expected to l a s t an average of 246 hours, or 10.25 days. This i s expect- ed to vary from 15.4 hours where a l l TSQ data are recorded to 48.2 days when no TSQ data are recorded, i i i ) Software Clock Real time i s maintained through a software clock that i s incremented upon the a r r i v a l of each synch byte and i s kept on the basis of a 10 synch bytes equalling one second. The time i s stored i n RAM locations, 200-204 of the data formatter with the i n i t i a l time being entered through the "SWTBUG" moni- tor (see Appendix 1-1). Table J - l gives the RAM time assignments which must be entered i n hexedecimal format when i n i t i a l l i z e d . 178 Table J - l RAM Time Assignments (pP#l) Location Assignment Month 0200 0201 Day Hour 0202 0203 Minute 0204 Second i v ) Data Formats There are two basic data formats outputted by the data processor (yP//2); a time series format and a d i s t r i b u t i o n series format. The time series format i s given i n Table J-2 and i s repeated for each one second record dumped. A minimum of 12 one second records are dumped preceding an event with new time series records being dumped as long as the event p e r s i s t s . The d i s t r i b u t i o n series format, on the other hand, i s given i n Table J-3 and i s dumped hourly even i f no propagation events occur. 179 Table J-2 Time Series Block Format Byte Description S p e c i f i c Comments 1 Record Type FE = Time Series Block 2 Months BCD 3 Days BCD 4 Hours BCD 5 Minutes BCD 6 Seconds BCD 7 Gauge Status HEX 8 Wind Direction Dog Mountain 9 Wind Speed Dog Mountain A Temperature Dog Mountain B R a i n f a l l Dog Mountain C Wind Direction Ruby Creek D Wind Speed Ruby Creek E Te-perature Ruby Creek F R a i n f a l l Ruby Creek 10 Wind Direct i o n 11 Wind Speed 12 Temperature 13 R a i n f a l l 14 Wind Direct i o n 15 Wind Speed 16 Temperature 17 R a i n f a l l 18 Wind Direction 19 Wind Speed IA Temperature IB R a i n f a l l IC Receiver 1 ID Receiver 2 IE Receiver 3 IF Receiver 4 20 Receiver 5 Bear Mountain Bear Mountain Bear Mountain Bear Mountain Agassiz Experimental Farm Agassiz Experimental Farm Agassiz Experimental Farm Agassiz Experimental Farm Ryder Lake Ryder Lake Ryder Lake Ryder Lake 3550 MHz F i r s t 100 msec. 3790 MHz F i r s t 100 msec. 4010 MHz F i r s t 100 msec. 7142 MHz F i r s t 100 msec. 7496.5 MHz F i r s t 100 msec. Table J-2 Time Series Block Format (cont'd.) Byte Description S p e c i f i c Comments 21-25 Second 100 msec. 26-2H Third 100 msec. 2B-2F Fourth 100 msec. 30-34 F i f t h 100 msec. 35-39 Sixth 100 msec. 3A-3E Seventh 100 msec. 3F-43 Eighth 100 msec. 44-48 Ninth 100 msec. 49-4D Tenth 100 msec. 4E EVENT INDICATOR cc = Fade 99 = Rain 4F-50 EOB TRAILER Two consecutive FF's Table J-3 Data Format for the D i s t r i b u t i o n Buffer Byte Description S p e c i f i c Comments 0 Record Type (FD) FD = D i s t r i b u t i o n Series 1 Month BCD 2 Day BCD 3 Hour BCD 4 Minute BCD 5 Second BCD 6 Data Type (01) Data Type Control Word 7-86 Dog Mountain Wind Direction D i s t r i b u t i o n 87-106 Ruby Creek 107-186 Bear Mountain 187-206 Agassiz Exp. Farm Wind Direction D i s t r i b u t i o n 207-286 Ryder Lake 287 FF T r a i l e r 288 FF 289 FF Table J-3 Data Format for the D i s t r i b u t i o n Buffer (cont'd.) Byte Description S p e c i f i c Comments 28A Record Type (FD) Header 28B Month 28C Day 28D Hour 28E Minute 28F Seconds Header 290 Data Type (02) 291-310 Dog Mountain Wind Speed D i s t r i b u t i o n 311-390 Ruby Creek 391-410 Bear Mountain 411-490 Agassiz Exp. Farm Wind Speed D i s t r i b u t i o n s 491-510 Ryder Lake 511 FF T r a i l e r 512 FF 513 FF 514 Record Type (FD) Header 515 Month 516 Day 517 Hour 518 Minute 519 Second Header 51A Data Type (04) 51B-59A Dog Mountain Temperature D i s t r i b u t i o n 59B-51A Ruby Creek 51B-69A Bear Mountain 69B-71A Agassiz Exp. Farm Temperature D i s t r i b u t i o n 71B-79A Ryder Lake 79B FF T r a i l e r 79C FF 79D FF 79E Record Type (FD) Header 79F Month 780 Day 781 Hour 782 Minute 182 Table J-3 Data Format for the D i s t r i b u t i o n Buffer (cont'd.) Byte Description S p e c i f i c Comments 783 Second Header 784 Data Type (08) 7A5 824 Dog Mountain R a i n f a l l D i s t r i b u t i o n 825-8A4 Ruby Creek 8A5-924 Bear Mountain 925-9A4 Agassiz Exp. Farm R a i n f a l l D i s t r i b u t i o n 9A5-A24 Ryder Lake A25 FF T r a i l e r A26 FF A27 FF A28 Record Type (FD) Header A29 Month A2A Day A2B Hour A2C Minute A2D Second Header A2E Data Type (10) A2F-B2E Receiver 1 (3550 MHz) Received Signal D i s t r i b u t i o n B2F-C2E Receiver 2 (3790 MHz) C2F-D2E Receiver 3 (4010 MHz) D2F-E2E Receiver 4 (7142 MHz) Received Signal D i s t r i b u t i o n E2F-F2E Receiver 5 (7496 MHz) F2F FF T r a i l e r F30 FF F31 FF J-2 The Ryder Lake 6800 Microprocessor Software The purpose of the Ryder Lake software i s to coordinate the sampling for both the meteorological variables and receiver sign a l amplitudes and transmit these on two l i n k s ; a low speed (110 bps) l i n k and a high speed (1200 bps) l i n k respectively to UBC. The software flow chart to do this i s given i n Figure J-4. The program starts by i n i t i a l i z i n g the ACIA I/O ports and A/D and 183 ( M A I N ") i INITIAIZE ACIA A/D STACK POINTER SEND SYNCH. = FFH SEND MET DATA SEND SYNCH. = FFH DEC MCOUNT l/IOSEC (" MASTER ) SAMPLE EACH VARIABLE 8 TRANSMIT Rx^CH^OOH Rx2=CH# I OH Rx. =CH#30H 4 SEND SYNCH. =FFH SAMPLE MET VARIABLES a STORE WD =CH#90H WS =CH#80H TEMP=CH#COH RAIN =CH#DOH IF DATA=FFH RESTORE AS F EH Figure J-4 Data A c q u i s i t i o n Flow Chart for the Ryder Lake Datalog 6800 Microprocessor. 184 then waits to sample data. The basic sampling i n t e r v a l i s 1/10 of a second at which time the receivers are sampled and t h e i r data sent. Every tenth i n t e r - v a l , that i s for each second, the meteorological variables are sampled and the data transferred to an output buffer for transmission. In t h i s way the received signa l l e v e l s are sent as soon as they are sampled, whereas the meteorological data are sent, one at a time, from an output buffer. The ACIA output ports at Ryder Lake are configured for one star t and one stop b i t which are matched by the UBC microprocessor data formatter input ports. J-3 The Weatherlog 8085 Microprocessor Software The purpose of the weatherlog software i s to coordinate a one second A/D sampling i n t e r v a l of the four meteorological vari a b l e s : wind speed, wind d i r e c t i o n , temperature and r a i n , and then send these data on the communication channel to UBC at a rate of 110 bps. The weatherlog software flow chart i s given i n Figure J-5 and i s the same for the Dog Mountain, the Ruby Creek and the Agassiz Experimental Farm s i t e l o c a t i o n s . As shown, the program s t a r t s by i n i t i a l i z i n g the stack pointer, the A/D channels and the software delay loop. Then a f t e r each second the variables are sampled and outputted through the SOD pin of the 8085 microprocesor to the communications l i n k . This cycle i s repeated every second which i s determined by a program delay loop. If any software changes are made to the main program software the delay loop must be r e c a l i b r a t e d . This i s f a c i l i t a t e d by monitoring the r a i n clear output con- nector of the microprocessor (see Figure 1-6) and using a frequency meter to measure the sampling i n t e r v a l . 185 V A R I A B L E a S T O R E A S F O L L O W I N G a ) C H N9'3 = W D b ) C H N9 4 : w s O C H N ? 5 = T E M P d ) C H N S « = R A I N t _ I F O A T A I S « F F H R E S T O R E D A T A A S = F E H _ _ S E N D _ W D _ S E N D W S S E N D T E M P S E N D S Y N C H « F F H Figure J-5 Program Flow Chart for the UBC Weatherlog 8085 Data A c q u i s i t i o n Microprocessors 186 J-4 The Bear Mountain 1802 Microprocessor Software Functionally, the Bear Mountain RCA 1802 microprocessor software shown i n the flow chart of Figure J-6, i s the same as the 8085 weatherlog. The only differences are i n the method by which the timing for the one second sampling i n t e r v a l and the 110 bps data stream are derived. Instead of using software derived delay loops as i s done i n the 8085 system the 1802 software r e l i e s on externally derived interrupt pulses to e s t a b l i s h sampling i n t e r v a l s and trans- mission timing. J-5 The NOVA 840 Minicomputer Data Transfer Software The purpose of this software i s to transfer data from the magnetic cas- sette recorder to the magnetic r e e l - t o - r e e l tape on the NOVA 840. The s o f t - ware flow chart for this data transfer operation i s given i n Figure J-7. After i n i t i a l i z a t i o n , the program f i r s t requests a block of data (2k bytes) from the cassette recorder by issuing an ASCII control command. The NOVA then converts the data to EBCDIC characters and outputs the block to the magnetic tape. After t r a n s f e r r i n g one block another i s requested for transfer and the process i s repeated. 187 C BEAR MTN. INITIALIZE A / D REGISTERS WAIT FOR I SEC INTERRUPT 6 SAMPLE/SEND SAMPLE EACH VARIABLE a STORE- a) TEMP. = CH. N2 5 b) RAIN=CH.N26 I F DATA=FFH RESTORE DATA AS= FEH SEND 9 9 H SEND CCH SEND SYNCH • FFH Figure J-6 Data A c q u i s i t i o n and Control Program Flow Chart for the Remote Bear Mountain 1802 Microprocessor Unit 188 J-4 The Bear Mountain 1802 Microprocessor Software Functionally, the Bear Mountain RCA 1802 microprocessor software shown i n the flow chart of Figure J-6, i s the same as the 8085 weatherlog. The only differences are i n the method by which the timing for the one second sampling i n t e r v a l and the 110 bps data stream are derived. Instead of using software derived delay loops as Is done i n the 8085 system the 1802 software r e l i e s on externally derived interrupt pulses to e s t a b l i s h sampling i n t e r v a l s and trans- mission timing. J-5 The NOVA 840 Minicomputer Data Transfer Software The purpose of this software i s to transfer data from the magnetic cas- sette recorder to the magnetic r e e l - t o - r e e l tape on the NOVA 840. The s o f t - ware flow chart for this data transfer operation i s given i n Figure J-7. After i n i t i a l i z a t i o n , the program f i r s t requests a block of data (3k bytes) from the cassette recorder by issuing an ACSII control command. The NOVA then converts the data to EBCDIC characters and outputs the block to the magnetic tape. After t r a n s f e r r i n g one block another i s requested for transfer and the process i s repeated. 189 c NOVA 8 4 0 I N I T I A L I Z E = C U R R E N T P O R T MAG T A P E R E A D B L O C K F R O M C U R R E N T P O R T C O N V E R T F R O M H E X T O E B C D I C S T O R E B L O C K ON M A G N E T I C T A P E c S T O P Figure J-7 Program Flow Chart to Transfer Data from Cassette Tapes to Magnetic Tape Using the Nova 840. 190 APPENDIX K THE BRIGHT BAND PROPAGATION EXPERIMENT'S DATA BASE MANAGEMENT SYSTEM K-1 Introduction This appendix gives the documentation to f a c i l i t a t e program development and maintenance of the data base management system (DBMS) used i n this bright band propagation experiment. As described i n Chapter IV, the data a c q u i s i t i o n system generates s u f f i c i e n t l y large volumes of data to make the bright band research project impractical unless a computerized data reduction, storage and analysis system i s u t i l i z e d . Thus the data handling function performed by DBMS i s an i n t e g r a l part of this research project since i t i s responsible to provide the data analysis and graphical outputs which are used to draw the ex- perimental conclusions. K-2 The System DBMS i s a sequential system where the input i s raw experimental data and the output i s given as a presentation of graphical r e s u l t s v i a p l o t t i n g rou- t i n e s . A functional flowchart r e l a t i v e to the bright band experiment showing t h e i r developmental status to the completion of this thesis work i s given i n Figure K-1. In terms of DBMS development, the entry procedure i s complete, and an integrated p l o t t i n g package which includes routines to plot attenuation with path average r a i n rate, i n d i v i d u a l r a i n rates, s i t e temperature, s i t e d i f - f e r e n t i a l temperature, d i f f e r e n t i a l temperature, temperature gradient and wind 191 £Xf>£.&/A>/£-A/rs4L £>ATA (FtfOAf A/OM A4//\Jf COMPUTER. 800 3 FORMAT COXPESPOAVDS TO DD ' /MPUT FORMAT . V . / \ TAPE P^EPAPED 3Y°THE EXTPACT MODE DBMS DATA ppocessor. D A T A t a p e s PLOTT/NG RO(JT/NES_, PIOTTED OUTPUTS Figure K-1 DBMS Functional Flow Chart Showing Completion Status 192 speed as a function of time, have been f i n i s h e d . Several DBMS packages are s t i l l under development and these include the "SCAN" function, the "EXTRACT" function and several "PLOT" routine options. A deta i l e d d escription of the major system software packages which com- pri s e DBMS are dealt with i n the following sections. These include the main DBMS program, the bright band "ENTER" function, the data directory, and the "PLOT" routine options. A l l these system packages use the Fortran IV-G compiler. K-3 DBMS Main The DBMS main program i n i t i a l i z e s the system and delegates program con- t r o l to user requested operating modes as shown i n i t s software flow chart given i n Figure K-2. At the present time the "ENTER" and "PLOT" modes are f u l l y integrated into DBMS, however, i t i s anticipated that the "SCAN" and the "EXTRACT" mode w i l l be incorporated into the system during the next phase of th i s research program. K-4 "ENTER" "ENTER" i s a conversion algorithm designed to convert recorded hex values to f l o a t i n g point engineering units for analysis. When the "ENTER" option i s envoked the disc f i l e or tape containing the hex information i s read, convert- ed to engineering units and then outputted to a temporary disc f i l e , "-DATA". These data can then be analyzed using "PLOT" or stored to permanent disc f i l e s or on magnetic tape using MTS "FILESAVE". 193 I smerevec. Figure K-2 DBMS Main Program Flow Chart 194 K-5 The Data Directory Each of the formats into and out of the DBMS entry procedure are sp e c i - f i e d by a data di r e c t o r y . Each item i n the directory i s separately and para- me t i c a l l y defined so changes can be made to i t without changing the executable software. Since the data directory defines the DBMS input and output formats, i t i s central to the development of new entry procedures for other experi- ments . A l i s t i n g of the data directory used i n the entry procedure for the bright band experiment i s given i n Table K-1. The let t e r e d labels for the column headings can be defined i n more d e t a i l , as follows: A. Record sequence number; a la b e l (not entered as part of the data d i r e c t o r y ) , B. F i e l d Name; descriptor of the data elements, C. Tape Type Number; 1 for output and 2 for input tape, D. Variable Type Number; "1" for 2 byte or 1 half-word size and "2" for 4 byte or 2 half-word size data f i e l d s , E. Starting byte position of this f i e l d i n the data record, F. Ending byte p o s i t i o n of th i s f i e l d i n the data record, G. F i e l d extraction parameter; gives the optional default s p e c i f i c a t i o n , H. Data variable encoding format. Table K-1 Data Directory for the Time Series Format A B C D E F G H 1 Record Type 2 1 1 2 BCD 2 Month 2 1 3 4 BCD 3 Days 2 1 5 6 BCD 4 Hours 2 1 7 8 BCD 5 Minutes 2 1 9 10 BCD 6 Seconds 2 1 11 12 BCD 7 Gaugestatus 2 1 13 14 HEX 8 Dog-Wind DN 2 1 15 16 00 HEX 9 Dog-Wind SP 2 1 17 18 00 HEX 10 Dog-Temp 2 1 19 20 00 HEX 11 Dog-Rain 2 2 21 22 00 HEX 12 RBY-Wind DN 2 1 23 24 HEX 13 RBY-Wind SP 2 1 25 26 00 HEX 14 RBY-Temp 2 1 27 28 00 HEX 15 RBY-Rain 2 2 29 30 00 HEX 16 Bar-Wind DN 2 1 31 32 00 HEX 17 Bar-Wind SP 2 1 33 34 00 HEX 18 Bar-Temp 2 1 35 36 00 HEX 19 Bar-Rain 2 2 37 38 00 HEX 20 AGZ-Wind DN 2 1 39 40 00 HEX 21 AGZ-Wind SP 2 1 41 42 00 HEX 22 AGZ-Temp 2 1 43 . 44 00 HEX 23 AGZ-Rain 2 2 45 46 00 HEX 24 RLK-Wind DN 2 1 47 48 00 HEX 25 RLK-Wind SP 2 1 49 50 00 HEX 26 RLK-Temp 2 1 51 52 00 HEX 27 RLK-Rain 2 2 53 54 00 HEX 28 01-RX1:3550 2 1 55 56 HEX 29 01-RX2:3790 2 1 57 58 HEX 30 01-RX3:4010 2 1 59 60 HEX 31 '01-RX4:7142 2 1 61 62 HEX 32 01-RX5:7496 2 1 63 64 HEX 33 02-RXl:3550 2 1 65 66 HEX 34 02-RX2:3790 2 1 67 68 HEX 35 02-RX3:4.010 2 1 69 70 HEX Table K-1 Data Directory for the Time Series Format (cont'd.) B H 36 02-RX4:7142 37 02-RX5:7496 38 03-RX1.3550 39 03-RX2:3790 40 03-RX3:4010 2 2 2 2 2 71 73 75 77 79 72 74 76 78 80 HEX HEX HEX HEX HEX 41 03-RX4:7142 42 03-RX5:7496 43 04-RX1.3550 44 04-RX2:3790 45 04-RX3-.4010 2 2 2 2 2 81 83 85 87 89 82 84 86 88 90 HEX HEX HEX HEX HEX 46 04-RX4:7142 47 04-RX5:7496 48 05-RXl:3550 49 05-RX2:3790 50 05-RX3:4010 2 2 2 2 2 91 93 95 97 99 92 94 96 98 100 HEX HEX HEX HEX HEX 51 52 53 54 55 05-RX4:7142 05- RX5:7496 06- RXl:3550 06-RX2:3790 06-RX3:4010 2 2 2 2 2 101 103 105 107 109 102 104 106 108 110 HEX HEX HEX HEX HEX 56 06-RX4.-7142 57 06-RX5:7496 58 07-RXl:3550 59 07-RX2:3790 60 07-RX3:4010 111 113 115 117 119 112 114 116 118 120 HEX HEX HEX HEX HEX 61 62 63 64 65 07-RX4:7142 07- RX5:7496 08- RXl:3550 08-RX2:3790 08-RX3:4010 121 123 125 127 129 122 124 126 128 130 HEX HEX HEX HEX HEX 66 08-RX4:7142 67 08-RX5:7496 68 09-RXl:3550 69 09-RX2:3790 70 09-RX3:4010 2 2 2 2 2 131 133 135 137 139 132 134 136 138 140 HEX HEX HEX HEX HEX 197 Table K-1 Data Directory for the Time Series Format (cont'd.) A B C D E F G H 71 09-RX4:7142 2 141 142 HEX 72 09-RX5:7496 2 1 143 144 HEX 73 10-RX1:3550 2 1 145 146 HEX 74 10-RX2:3790 2 1 147 148 HEX 75 10-RX3:4010 2 1 149 150 HEX 76 10-RX4:7142 2 1 151 152 HEX 77 10-RX5:7496 2 1 153 154 HEX 78 EVENT FLAG 2 1 155 156 HEX 79 FF END OF BLOCK 2 1 157 .158 HEX 80 FF 2 1 159 160 HEX K-6 "PLOT" "PLOT" i s an integrated i n t e r a c t i v e p l o t t i n g package s p e c i f i c a l l y designed for presenting the recorded measurements i n a graphical time series format. The p l o t t i n g options developed i n work are as follows: 1. Rain rate and one receiver s i g n a l versus time; 2. Temperature - a) s i t e temperature and one receiver s i g n a l versus time, b) s i t e d i f f e r e n t i a l temperature and one receiver s i g n a l versus time, c) s i t e to s i t e d i f f e r e n t i a l temperature and one receiver s i g n a l versus time, d) temperature gradient and one receiver l e v e l versus time; 3. Site windspeed and one receiver l e v e l versus time; 4. Two receiver signals versus time (one second average); 5. High res o l u t i o n two receiver l e v e l s versus time ( a l l 1/10 second sample p o i n t s ) . 198 In a l l these plot options the scales and of f s e t s are i n t e r a c t i v e l y adjustable. The "PLOT" package takes source data i n engineering units from the "-DATA" tempory f i l e , processes i t for the pl o t t e r into another temporary f i l e c a l l e d "-PLOT#". The plot can then be previewed using PLOTSEE and routed for output to the CALCOMP plotters or to a printron i x p r i n t e r (RMPROUTE=PTRXPLOT for the best output). A sample p l o t t i n g rum i s given i n Figure K-3. 199 PROPAGATION DATA P L O T T I N G SYSTEM S E L E C T OUTPUT OPTION REQUIRED ( E N T E R FUNCTION NUMBER) ( 1 ) T IME S E R I E S PLOT OF ONE R E C E I V E R S IGNAL STRENGTH AND ONE RAIN RATE ( 3 ) TIME S E R I E S PLOT OF ONE R E C E I V E R SIGNAL STRENGTH ANO ONE OF S E V E R A L TEMPERATURE D ISPLAY OPTIONS ( 3 ) TIME S E R I E S PLOT OF ONE R E C E I V E R S IGNAL STRENGTH AND WIND SPEED ENTER CODE FOR SOURCE F I L E D E S I R E D : t »> TEST SCRATCH F I L E " - D A T A " 2 •> PERMANENT DISK F I L E " D O 0 1 . D A T " I . ENTER S T A R T I N G RECORD NO. TO BE P L O T T E D : (16) 1 . ENTER NO. OF RECOROS TO BE P L O T T E D : (16) 8 0 O 0 . PLOT WILL D I S P L A Y BCOO R E C O R D S . S T A R T I N G WITH NO. t ARE D E F A U L T V A L U E S OF F I R S T RX . S IGNAL L E V E L D I S P L A Y OK? O R I G I N VALUE • - 4 0 0 0 INCREMENT • 5 . 0 0 ENTER "<CR>" DR "NO * NO ENTER O R I G I N V A L U E : ( F 5 0} - 6 5 . . ENTER INCREMENT V A L U E : ( F 5 . 0 ) 5 . . ARE O E F A U L T VALUES OF SECOND RX. S IGNAL L E V E L D I S P L A Y OK? O R I G I N VALUE - - 4 0 . 0 0 INCREMENT • 5 . OO ENTER "<CR>" OR "NO" NO ENTER O R I G I N V A L U E : <F5.0> - 5 0 . . ENTER INCREMENT V A L U E : ( F 5 . 0 ) 5 . . ENTER D I S P L A * RESOLUTION C O O E : t -> ONE P L O T T E D POINT PER SECOND 2 -> TEN P L O T T E D POINTS PER SECOND 1 . ARE D E F A U L T VALUES OF TIME AX IS D I S P L A Y OK? O R I G I N VALUE • 0 0 INCREMtNT - » . O O ENTER •<CR>* 0 « "NO" NO ENTER O R I G I N V A L U E : ( F 5 . 0 ) O . . ENTER INCREMENT V A L U E : ( F 5 . 0 ) • O . . FOR F I R S T R E C E I V E R C H A N N E L : ENTER R E C E I V E R NUMBER TO BE S E L E C T E D : 1 •> 3550 MHZ. 3 •> 3990 MHZ. 3 >> 4 0 1 0 MHZ. 4 •> 7143 MHZ. 5 •> 7496 M H ? . 3 . FOR SECOND R E C E I V E R C H A N N E L ; T Y P I C A L R E S U L T S : ( INCHES) STRENGTHS S E Q . N O . X RX . 0 1 R X . #3 PLOT 1 1 OO 5 . 8 8 1 83 1301 3 . 0 0 5 . 8 3 0 . 3 7 3401 5 . 0 0 5 . 5 0 0 . 4 4 3601 7 . 0 0 5 . B 6 1 . 4 5 4801 9 . 0 0 5 . 6 9 0 . 9 1 6001 11 . 00 5 . 7 4 o.ee 6003 1 1 . 0 0 5 . 74 0 . 9 2 S U C C E S S F U L L Y REAO 8001 DATA RECORDS P L O T T I N G WILL TAKE APPROX. 3 MIN. 53 S E C . MAXIMUM Y VALUE IS APPROX. 10 INCHES. 0 MIN 51 S E C , OR 33% OF TOTAL PLOT TIME S U C C E S S F U L P L O T . f E x e c u t I o n l a m i n a t e d 0 % 16. 13 , $4 1 87T #SET RMPROUTE-PTRXPLOT * $ 0 1 . J 4 1 . B 9 T #R • P L O T SE E 0 - - P L O T * • E x e c u t i o n B e g i n s AND 14 INCHES OF PAPER IS WITH PEN U P . I-LII--I- ;v„v . i- j. -j --J j— • - - i i- i IG? PX • R M P R I N T * a s s i g n e d J o b number 463548 P r l n t r o n l x p l o t g e n e r a t i o n d o n e . IG? PX P r l n t r o n l x p l o t o e n e r a t i o n d o n e . IG? PX P r l n t r o n l x p l o t g e n e r a t i o n d o n e . IG? E n d o f p l o t s . L a s t c h a n c e t o u s e * I G . IG? $ • R M P R I N T • RM462548 r e l e a s e d t o PTRXPLOT 6 p a g e s PRIORITY-NORMAL O E V I C E T Y P f ' P T R X * E « o c u t l o n T e r m i n a t e d Figure K-3 Sample Plotti n g Run 200 REFERENCES Van Trees, H., Hoversten, E., and McGarty, T., "Communications S a t e l l i t e s : Looking into the 1980's", IEEE Spectrum, pp. 43-51, Dec. 1977. GTE Lenkurt, Engineering Considerations for Microwave Communication Systems, 1970. Sil v e r t h o r n , D. , and Tetarenko, R., "Microwave Radio Spreads TV", T e l e s i s , v o l . 5, pp. 209-213, 1976. HervieUx, P., "RD-3: an 8 GHz D i g i t a l Radio System for Canada", T e l e s i s , v o l . 4, pp. 53-59, 1975. Anderson, C. , Barber, S. , and Patel, R. , "Propagation Experiments Show Path to Success", T e l e s i s , v o l . 6, pp. 180-185, 1977. 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