Radio transmitter/receivers with non interferring local oscillator frequency

Claim 1

A radio transmitter/receiver comprising: a transmitter; a superheterodyne receiver, and a local oscillator for supplying said transmitter and receiver with local signals at a plurality of frequencies; said transmitter and receiver operation on a plurality of radio channels with different transmission and reception frequencies for each channel said transmission and reception frequencies being a natural number multiple of the frequency spacing between said radio channels and the output frequencies of said local oscillator being between the transmission frequencies of two adjacent channels mixing means in said receiver for mixing an output from said local oscillator with a reception frequency to provide an intermediate frequency f if wherein said intermediate frequency f if of said superheterodyne receiver is set to have a value expressed by f.sub.if =(2K-1)×f.sub.ch /2 where f ch represents a frequency spacing between radio frequencies assigned to adjacent channels, and K represents a natural number.