[VHFcontesting] DEM Transverters With Common IF Connection

N6FD n6fd at hughes.net
Sat Dec 15 16:54:09 EST 2012

I did this with my old 1296 transverter using an unused section on the 
T/R relay.  It has withstood a couple of inadvertent transmits on two 
meters with 10W SSB.

73, Erich N6FD

On 12/15/2012 7:10 AM, Jimk8mr at aol.com wrote:
> Not precisely a contesting question, other than it concerns my VHF
> contesting station. But rather than subscribe to some other reflector for advice
> on one question, I'll pose it here.
> I recently replaced the TS-830S that had been the IF radio for my
> transverters  (222-432-1296) with a KX3. While I still also have a  HR-2510 that I
> can use, clearly the KX3 would be a big improvement over  that. However, the
> KX3 won't provide the separate RX and TX IF inputs for the  DEM transverters.
> Has anyone had experience with modifying the DEM transverters for a common
> IF input/output?
> It appears that there is a unused half of the DPDT relay that switches  the
> DC between TX and RX. Does anybody know of any reason that could not be
> used  for switching the 28 MHz IF signal? Would 100 mw (or somewhat more) of
> 28MHz RF to the output of the RX chain  (i.e. if RF was applied without the
> relay switching, either with or without power on the last RX stage) be of
> concern?
> Any other issues to be concerned with?
> 73  -  Jim   K8MR
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