Re: Using Vacuum Tube heathkit as Linear Amplifier for QRP

Bill Cromwell

Hi Richard,

I copied the whole thing from one of the ARRL Handbooks. I'm sure I can find it again. I will have a look. I do still have the T-R switch and maybe even the coupling capacitor. That cap is a "gimmick" made from about three inches of RG-58. Don't let the "gimmick" label throw you over. It is more than a little twisted pair as sometimes used in receiver circuits for regenerative feedback.

I built mine in an old TV tuner metal box. I don't know what they have in TV sets for a tuner these days but I think it is an SDR front-end. An Altoids tin (or something similar) would work. The transistor is a 40673 dual gate mosfet and is now just about unobtanium. Fortunately there are plentiful substitutes. You could also use a vacuum tube <grin>.

More later after I dig out the details. It is so easy that even *I* could do it.


Bill KU8H

On 11/12/19 4:07 PM, Richard Spohn wrote:
Bill, do you have the schematic for the solid-state T/R switch, or
even better, do you still have that switch? I am keenly interested in
an all-electronic (no relays) T/R switch for QSK. Building one from
scratch may be slightly outside my skill set tho. -- Rich WB2GXM
bark less - wag more

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