Dylan's 5 Tube TRF Radio

This five-tube TRF receiver started life as a homebrew that was likely built in the mid-1920s. It originally had 1923 and '24 style brass based 201As, but I haven't dated the other parts. It appears that the original builder used a Neutrodyne parts kit (tuning caps, neutralizing caps, and coils) from Bremer Tully. When I received the set, it was in such bad shape that I started dismantling it for parts. Many solder joints could be pulled apart with little effort. Also, everything was covered in decades worth of dust and oxidation.

After it sat for a few years, I recently decided to build my own TRF set using the parts from it. I set to work dismantling and cleaning and polishing all of the components, and I made a new base board with some scrap wood that I had. The bakelite panel shined up nicely with soap and water, and I added some brass flathead screws where the original builder had scribed crude lines above the dials. I also kept the original binding post strips, which sit a bit crooked as they weren't drilled perfectly.

After everything was cleaned up, I secured all my parts to the board according to where they were in the original set. I had torn up the old wiring, so I had to come up with my own schematic to work with. I borrowed ideas from other 1920s sets and received a few tips on taming oscillation from master homebrewer Bill Meacham. This set also gave me my first taste of working with square buss wiring, which I bought from Antique Electronic Supply. Wiring a radio with this stuff is more like solving a puzzle!

I used modern components in three places. A modern .22µF poly-film decoupling capacitor is wrapped in black paper and equipped with solder tabs on each end. Two carbon film resistors are secured inside aluminum standoffs with cardboard washers and solder tabs. They don't replicate original parts, but simply look more appropriate this way.

This radio is no outstanding performer, but so far it will grab the big stations along the West Coast (I am in Oregon) as well as a few smaller ones here and there. I will be building and using two wave traps in order to tame the local stations. Located at 1110 and 1240, these two completely own the upper end of the dial.

I'll quit talking now, and let the pictures say the rest!

Pictures