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Re: xmit inhibitor

on 2/26/03 11:57 AM, Kyle Yoksh at yokshs@planetkc.com wrote:

> I receive AO-40 at 145 mhz, and occasionally use a second rig to receive
> AO-40. I also occasionally use these rigs to transmit, so I don't want a
> permanent 'no-xmit' mod. A small circuit mounted in the shack would work
> well.

Using W9AE's transmit inhibit mod is a real simple way to work it.  And it's
not a permanent transmit inhibit.

It is for an FT-847 but the principle can be applied to other rigs as well.

What you do is have an internal relay that you add inside the rig.  This
relay is used to connect and disconnect the PA bias line.  No bias, no
transmit.  The default state of the relay is to have the bias turned on.
You run the control lines of the relay out the back of the rig.  You then
turn this relay on and off with an external switch.  Also connected to that
switch is a coaxial RF relay.  You connect the 2m antenna to the NC side of
the relay and the S band to the NO side.  When you turn your switch on, you
switch antennas and you disconnect the PA bias.  Very simple.  You pretty
much can't transmit into the d/c this way.

Wayne's mods are at:


It takes minutes to do.


Jon Ogden
NA9D (ex: KE9NA)

Citizen of the People's Democratic Republik of Illinois

Life Member: ARRL, NRA
Member:  AMSAT, DXCC

http://www.qsl.net/na9d   <- Updated on 1/22/03!!!

"A life lived in fear is a life half lived."

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