Philips SFM114/00 Wobbulator (1952)

According to manual, the SFM114/00 was designed by Philips Telecommunication to “adjust intermediate frequency amplifiers operating at 1.5 MHz or 9.72 MHz”. Whereas most of today’s personal mobile radio (PMR) equipment have first IFs of 10.7 MHz or 21.4 MHz, the use of 1.5 MHz and 9.72 MHz was common practice in the 1950s and 1960s.