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Friday, March 22, 2019

Music to my ears

It works!

Last night I completed the under-the-chassis wiring of my Push Pull Colpitts transmitter. I ended up doing "bus bar" wiring. It gives a 3D effect and worked well for this design/layout. Between that and the wooden chassis this one feels like a '29 transmitter. Most of the under the chassis parts are 40s vintage but, hey, they will be hidden.
 This morning I connected power for an initial checkout. With 300V on the plates and about 20 watts input I'm getting over 10 watts out of sweet sounding RF on 80. The grounded tuning/tank capacitor effectively eliminates the detuning effect of hand capacity and I'm certainly not going to complain about 50% efficiency. Open circuit voltage across the key terminals is only 48 volts so that's good too.

 Next I'll clean up the operating position and finish my 40 mtr coils so that I can test it there.

1 comment:

Don Dulmage said...

Seems to be a push pull wave sweeping the vintage community. Congrats. And a Colpitts at that!