KC9KEP - A work in progress



  Homebrew Radio Projects - 1941 ARRL 7-Tube Superheterodyne

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1941 single signal superhet

Hello all!

Well, my insane preoccupation with building the various ARRL receivers for the 1941 era is complete .. that's all the 1941 superhet HF radios that they published for that year!

But, as they say, "If you can't hear 'em , you can't work 'em!"
And wanted a receiver that gives me enough selection to do some QSO's on CW .. or phone.  I hope that this receiver will do that  :-)
This set operates very much as a "bona fide store bought receiver" does!  (At least, to me it does!)

This is the ARRL 7-tube, single signal superheterodyne receiver featuring regenerative feedback in the RF front-end tuning, and additional/optional feedback in the I.F. stage to provide the "single signal effect".

This is the first radio for which I've wound a full compliment of tuning coils.  And, I've re-designed the face of the National ICN dial to reflect the available frequencies.

Of course, I've laid-out & had the front panel Laser engraved to match this series of radios.

I was very lucky to have located the permeability tuned 455 kHz I.F. cans and BFO, exactly as specified in the original ARRL article.

I've added the output transformer & 3 X 5" onboard speaker to the original layout.

The top-row of controls (from L to R) are: RF Tune, Bandspread, and Bandset.
The bottom-row of controls (from L to R) are: RF regeneration, I.F. Gain, Volume, and BFO.

The BFO fine tune variable capacitor has a small corner of one plate bend sideways.  The BFO is "turned-off" by rotating the control to the point where the capacitor plates just touch, killing the BFO oscillations.