The TM-1 / TL-2 Short Haul Microwave Systems

TECHNICAL VOLUME XLV Copyright © 1966, J A N U A R Y 196(5 American JOURNAL NUMBER 1 Trlegraph Company Telephone and The TM-l/TL-2 Short Haul Microwave Systems By R. W. FRIIS, J. J. JANSEN, R. M. J E N S E N , and H. T. K I N G (Manuscript received July 15, 1965) This -payer describes the design and discusses the performance of the TM-1 and TL-2 radio relay systems designed for short haul service in the 5.925 to 6^25 megacycle and the 10,700 to 11,700 megacycle common carrier bands, respectively. Used as a crossband diversity pair, they provide a highly reliable broadband message channel for up to 600 circuits and require little maintenance and relatively low power. These systems are also used to transmit television. TABLE OF CONTENTS I. I N T R O D U C T I O N AND BACKGROUND I I . SYSTEM O B J E C T I V E S I I I . ENGINEERING CONSIDERATIONS I V . T R A N S M I S S I O N PLAN V . MICROWAVE M U L T I P L E X I N G N E T W O R K S V I . RADIO T R A N S M I T T E R S V I I . RADIO R E C E I V E R S V I I I . P O W E R SYSTEM I X . EQUIPMENT DESIGN FEATURES X . TIIE I N I T I A L INSTALLATION X I . TELEVISION TRANSMISSION X I I . ACKNOWLEDGMENT APPENDIX REFERENCES 1 3 5 10 16 19 40 63 72 83 87 93 94 94 r. INTRODUCTION AND BACKGROUND Bell System short haul microwave was launched in 1958 with the completion of the development of the 11 -gc TJ Microwave 1 (3 T H E BELL SYSTEM TECHNICAL JOURNAL, JANUARY 1966 Radio Relay System. 1 Generally well received, this all-electronic tube system suffered somewhat from an economic standpoint because of its relatively large power requirements (just under onehalf kilowatt) and the expense entailed in providing standby power at remote locations.