> A bandpass/or lowpass would probably be a good idea on the 6 m amp.
> What I did was took an Drake KW HF LP filter and tweaked it up to reduce the
> loss at 50 Mhz…
> and that worked very well in killing the FM broadcast problems I had ages
> ago…I use the filter now
> with the KW.
> You might want to do the same… it wasn’t difficult to adjust.
> 73 Dana
> VE3D
> On Jul 29, 2015, at 12:34 PM, Steve Kavanagh <sjkavanagh1@yahoo.ca> wrote:
>
> Here's a question for some of you more experienced multi-ops. At our recent
> CQ WW VHF Contest operation in FN05 we had some interference from the 6m
> transmitter into the 2m receiver. It wasn't totally prohibitive but it was
> annoying at times...we had to stop transmitting on 6m while attempting EME
> contacts on 2m, for example. The setup and tear-down were done in a great
> hurry this year, so we had no time to investigate properly. I'd like your
> suggestions as to the most likely route by which the interference was getting
> in and how to fix it.
>
> The 2m station was as follows: Elecraft K2 - DEMI transverter - DCI bandpass
> filter - TE1452G amp - Bird43 - antenna.
> The 6m station was as follows: Kenwood TS-2000 - TE0552G amp - Bird 4304 -
> antenna.
>
> The two antennas were around 30 ft apart and at the same height.
>
> My first guess is that there is some transmitted noise at 144 MHz from the 6m
> rig/amp which got into the 2m antenna. That could be eliminated by a low
> pass filter or stub on the 6m output. Are there other possibilities I should
> consider before we try this again? The 6m amp was run from a switching power
> supply, which makes me wonder a bit. Radiation from the 6m amp power cables
> or ingress into the 2m station somewhere after the DCI filter (or on power
> lines) might be other possibilities.
>
> What do you think?
>
> 73,
> Steve VE3SMA
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