Wireless of the Week - week 25

[Bruce Parker (RIP)]

This week is a little known reception set, the R.P.A. 3. I have never seen an actual example and its development and purpose is a mystery. Any assistance to fill in these details would be most welcome, as would what “R.P.A.” stands for, the manual is silent.

The R.P.A 3 was built by Stewart-Warner-Alemite Corporation of Canada in 1943 which is an odd manufacturer for Canadian wireless equipment and one that didn’t seem to produce any other land sets. It operated on either 110 or 220 volts at 25 or 60 cycles and the manual says it was for stationary or vehicle use. It also had a send/receive switch that put the receiver on standby while some separate transmitter was sending. This infers the R.P.A. 3 was intended to be used alongside a transmitter, the likely candidates being the Wireless Sets No.12, 33 or 53. If this is correct, it seems to be a Canadian alternate for the Reception Set R107.

The set is 20” wide by 22” tall by 15” deep and weighs 130 lbs. It is housed in a steel case that has dome fasteners for a waterproof cover. On the top is a ‘power deck’ that housed the power supply unit, speaker and crystal calibrator as well as a wire antenna and parts box for spare valves and to store the earphones when not in use. The lower portion is the receiver itself. It covers an AM frequency range from 1.5 to 30 MHz in four bands. Reception could be achieved either with the antenna or by line transmission over wires attached to two binding posts on the back of the set.