GB650446A - Improvements in or relating to radio relay systems - Google Patents

Abstract

650,446. Two-way transmission. MARCONI'S WIRELESS TELEGRAPH CO., Ltd. Feb. 27, 1946, No. 6184. Convention date, Oct. 26, 1943. [Class 40 (iv)] [Also in Group XL (c)] In a radio relay system each repeater station' comprises a transmitter and two receivers, all operating on different carrier frequencies, and arranged so that reception by either of the receivers of carrier currents to which it is tuned causes it to be associated with the transmitter and disconnects the output of the other receiver during the reception period, thus conditioning the system for one-way use. As shown in Fig. 1 three frequencies are employed and are allotted to the transmitters (T) and receivers (R) as indicated by the subscripts 1, 2, and 3; the distances between stations being sufficiently large for transmitters using the same frequency to be substantially non-interfering. Control of unmanned repeater station (Fig. 2). Receivers R1, R3 are tuned to signals from West and East respectively, and transmitter T2 radiates in both directions. Reception of carrier by R1 or R3 causes the operation of electronic relay 41 or 42 respectively, whereupon the corresponding one of the relays 44 or 45 comes up over normally closed contacts of the other. If receiver R1 responds first, relay 44 energizes winding 50 of the polarized relay, and relay 53. The consequent closure of contacts w connects the output of receiver R1 to the input of the modulator in transmitter T2, and the operation of relay 53 connects up the transmitter power supply. The operation of relay 44 prevents relay 45 coming up should R3 subsequently respond to incoming signals, and ensures that conditions for one-way transmission are maintained. If receiver R3 is the first to respond to signals, operation of relay 45 controls the establishment of similar conditions for E.-W. transmission, energization of relay over winding 55 closing contacts e.