Racal RA17L Communications Receiver, 1962.

The RA17 series of communication receivers were first produced in the the 1950s - high quality valve sets originally designed for supply to the British Navy. The design proved so successful that they were ultimately used by all the military services. The BBC installed banks of them in their monitoring station. RA17L was the particular receiver which put Racal on the map, introducing the Wadley Loop circuit which divides the high frequency range into 30 smaller bands, each 1 MHz wide, cleverly eliminating frequency drift. The total frequency range covered by this receiver is 500KHz to 30MHz.