QST Aug 39 51F RCVR
Until the outbreak of WW 2, Collins Radio was primarily a transmitter and transmitter related component supplier. Many people think that Collins did not make receivers until during and after WW 2. There is an exception. In August of 1939, Collins introduced the rack mounted pull out 51F commercial receiver that operated from 1.5 to 20 mHz. What happened to the 51A through E, we can only ponder.