Adjacent-channel low-power mobile transmitter-receiver

Description of 10 W equipment, Type FT-153-10, for, use in the 148-174 Mc/s range. The phase-modulated transmitter uses a crystal-controlled Miller-type oscillator, whose frequency is multiplied 36 times in 4 stages, the output of the, fourth stage driving two Type 5812 beam power valves in class C push-pull operation. The receiver is a double-conversion superheterodyne with a first i.f. of 3.8 Mc/s. and a second of 455 kc/s. Conversion to 3.8 Mc/s makes it possible to reject the adjacent charnel, by means of the band-pass tilters in the first i.f. amplifier, sufficiently to minimize desensitization and, carrier intermodulation at this point. The major part of the receiver's selectivity is due to the interstage quadrupletuned dissipative band-pass filters of the second i.f. amplifier. Synchronous vibrators are used for the h.v. supplies of both the transmitter and the receiver.