In the 1920s and into the early 1930s, tuned radio frequency (TRF) receivers were the norm. Experimenters and manufacturers were still feeling their way with radio receiver design and felt comfortable with TRF circuits despite their increasingly obvious limitations.

By then, however, the more adventuresome were experimenting with superheterodyne receivers. In fact, a few superhets such as the RCA 26 (see SILICON CHIP, August 2008) were already being sold in Australia and overseas. Despite this, superhets were very thin on the ground, as very few people understood this "tricky" new technology.

The Raycophone "Pee-Wee" is a compact unit that's housed in an attractive wooden cabinet. The lack of a dial and indistinct markings around the tuning knob makes it difficult to tune to a wanted station.

The chassis is easy to remove but care must be taken to avoid damaging the under-chassis components.The parts mounted on the top of the chassis are all easily accessible.

The Raycophone company

One interesting Australian company at that time was Raycophone Pty Ltd. This company was run by Raymond Allsop who was both the director and the chief engineer. Radio was just one aspect of his involvement with electronics, his main interest being with sound movie equipment in the pre-WW2 era.

At that time, Raycophone was still relatively unknown as far as radio was concerned. And despite some considerable research, I have been unable to discover when they commenced operation and when they closed. The only reference to the production of radio receivers is in the "Radio Trade Annual and Service Manual" for 1939, which contains circuits and rudimentary technical information on several receivers produced by Raycophone in 1933.

However, I have been unable to find any circuits in the "Australian Official Radio Service Manuals".