The BC-224D is a WW II aircraft long distance liaison receiver for a 14 volt system. Tuning rage is 1.5 MHz to 18 MHz in 6 bands. It is externally nearly identical to BC-348 models and electrically similar except for the supply voltage. All BC-224 were designed for 14 volts. All BC-348 models were designed for 28 volts.
Made by RCA, this BC-224D has a 1942 contract date - serial number 61.
Pix date 1996. The SO-239 antenna connector and the power switch are ham radio modifications.
RCA built the first BC-224A, which looks more like the BC-312 than the later BC-224 models. Their redesigned BC-224B was the basis for further models. RCA also designed a 28 volt variation of the BC-224B which was designated the BC-348B. With the more common use of 28 volts in bombers and other aircraft, many more BC-348 sets were produced than BC-224. Variations among BC-224 and BC-348 models include changes to newer single-ended tubes rather than double ended and the newer octal 6K6 for audio output in place of the older six-pin type 41.For an historical summary, see BC-224 and BC-348 Aircraft Radio Receivers by Ken KF6NUR.