[AMRadio] Re: GB> 160m AM receiver project


Larry Szendrei ne1s at neandertech.com
Tue Oct 28 12:24:33 EST 2008


One project on my round-tuit list is to take an old AA5 junker, from which
I robbed the IF transformers long ago, into a QRP 160M AM MOPA
transmitter. I would use the local oscillator as the VFO, driving a pair
of 25L6s in parallel or push-pull, with another pair of 25L6s as plate
modulators. Then choose the VFO tube and low-level audio tubes such that
the series combination of those heaters is in the 18 - 24V range, which,
in series with the 4- 25L6s, adds up to 118 - 124V for operation directly
off the line. A solid-state rectifier would be used.

Heck, might even be able to double in the final for 2-band operation.

This would be a nice power level for running barefoot when conditions
allow, or feeding a linear amplifier for more oomph, and be a bit of a
novelty rig. I would use the original AA5 chassis and cabinet.

-Larry/NE1S


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