GB584513A - Transmission of signals by two-way radio communication with directional aerial - Google Patents

Abstract

584,513. Wireless signalling. PATELHOLD PATENTVERWERTUNGS- & ELEKTRO HOLDING AKT.-GES. July 10, 1944, No. 13169. Convention date, July 26, 1943. [Class 40 (v)] In a combined transmitter and receiver for ultra-short waves, a transmitter 1 has a dipole aerial 3 which is arranged at an adjustable acute angle to the receiver dipole 2. For reception, a certain proportion of the carrier wave emitted from the transmitter is received by dipole 2 together with the desired signal and heterodyned at 4 to give an intermediate frequency which is selected by filter 5, amplified at 6 and detected at 7. Small deviations in the received frequency may be corrected for by making a corresponding variation in the transmitter frequency. Alternatively, the resulting intermediate frequency may be heterodyned a second time with the output from a variable frequency oscillator to give a final true intermediate frequency, Fig. 2 (not shown). In a further modification, the transmitter is modulated by an adjustable auxiliary frequency and one of the resulting side bands is used to heterodyne the received signal. In this case, the auxiliary frequency is brought into operation by an automatic switching device at the end of the transmission of a message.