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Friday, October 24, 2014

2014 Bruce Kelley 1929 QSO Party

This year's AWA 1929 QSO Party is only about  1 1/2 months away.
The Feb 1931 QST cover inspired me to pull my SW-5 off the shelf to pair with my Hartley transmitter.

I found feedback within the SW-5 to be a problem. This isn't too bad for casual listening but it is a real problem for  on-the-air operating. Checking through my QST files I found the James Millen Sept 1931 article describing the design process for the SW-3. In it he talks about various shielding options. The SW-5 shielding looks a lot like Millen's first attempt at SW-3 shielding. He described the results as "most disappointing" and "the RF stage oscillated violently". My no holes solution? Turn the tuned SW-5 RF stage into an untuned RF stage. I inserted an RF choke and an antenna coupling capacitor into an empty SW-5 coil form and use it instead of a standard RF stage coil. Now the SW-5 RF stage stays out of oscillation and it still picks up plenty of 80 and 40 meter signals.

It looks like I may be able to use my new QSL cards after all.