Re: Using Vacuum Tube heathkit as Linear Amplifier for QRP

Richard Spohn

MFJ "Pin Diode Rig"....a model or part number?

On 11/12/19, Gordon Gibby <docvacuumtubes@...> wrote:
There is this MFJ pin diode rig that I managed to pick up on ebay for
$100. You might look around for another of those. They do take some
tinkering I'm told.

An even easier solution is to simply emulate the HW-16 and have TWO devices
--- one used for transmit and one used for receive -- and control both of
them with the same digitally created frequency (from a Raduino) and just
use diode protection of the input of the "receiver" just as many qrp rigs
do. There are probably a lot of schematics out there for creating a
diode switch also.


On Tue, Nov 12, 2019 at 4:08 PM Richard Spohn <wb2gxm@...> 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

On 11/10/19, Bill Cromwell <wrcromwell@...> wrote:

In the 80s I built boots for an Ten Tec Argonaut 509 using the carcass
of a Heathkit DX-35. There is no receive circuitry involved. I biased
the single 6146 for class AB1 operation. I built a solid state T-R
antenna switch to keep the QSK feature of the 509. It served me for a
several years and then the 509 moved to a new home. The remains of the
DX-35 also went to another ham.

I have the CW portion of a Heathkit DX-100 down for overhaul. The AM
phone parts were all gone when I got the DX-100. I am going to dpo the
mods to include the linear operation in phone mode to amplify SSB
signals and keep the class C operation for it's CW operation - ala the
Apache (TX-1). Grid block keying has already been part of this
particular DX-100.

Sometimes QRP is just not enough.


Bill KU8H

On 11/10/19 7:35 AM, Don Richards wrote:
Hi Gordon
I ran across this a while back but never tried it.

73 Donve3ids
bark less - wag more

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