[Heathkit] DX-20 T/R Switching?

[Ed - K9EW]

Hi Curt,

It does seem like an obvious oversight that the DX-20 doesn't have an
accessory socket, or at least an ac receptacle that is swiched by the
Transmit switch on the front panel.

I leave my DX-20 in the transmit mode during a QSO, then switch it
back to Standby when I'm done.  If I'm doing a lot of operating, I
will switch to Standby during the Receive part of a QSO.  I use a
footswitch to activate the antenna changeover relay.

If you don't mind putting a hole in the back apron of the DX-20, you
can do what has already been suggested by making the Transmit switch a
DPDT, and using half of it to activate the antenna relay.

Another approach would be to build an RF activated antenna switch.  It
would sense when there is RF at the transmitter output connector, and
activate a relay that switches the antenna and grounds the input to
the receiver.  MFJ makes one of these, and I've also seen them on the
Internet.  That way, there's no modification to the DX-20.

Hope this helps.

73,
ed - k9ew
www.k9ew.us

On Wed, Aug 25, 2010 at 2:21 PM, Curt <rhulett1 at comcast.net> wrote:
> I built a relay box to switch antenna between transmit and receive for a
> recently acquired DX-40.
> Contemplating acquiring a DX-20, was surprised to notice it has no provision
> for providing switched power
> for a relay.  Never having owned any Heathkit transmitter in my old Novice
> days, am wondering how folks
> performed T/R switching with the DX-20 or AT-1?
>
> 73, Curt KB5JO
>
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