On Thu, 2007-12-13 at 09:47 -0500, Paul Christensen wrote:
> > biases weren't enough or the UHF signals were strong enough. Using true
> > HF PIN diodes instead of switching or 1N4007 should also help prevent
> > that mixing. And the external TVI filter has been proven effective in a
> > couple such cases.
And you reduced TVI causing harmonics which occasionally made for
> I agree with Gerald. Something is occurring between the antenna port and
> the BPF matrix. As I indicated in my last message, when I placed the Nye
> Viking LPF on the output of the Omni Six, the problem was completely
> solved -- but that was before I changed the T/R diodes to the high-voltage
> PIN types.
> But what I did not do in the 13 years thereafter was to check for the
> problem after the PIN diodes were installed. The Viking filter was so
> unobtrusive that it just stayed there, out of sight, out of mind, for the
> duration. Since the filter has negligible loss below 30 MHz, I felt that
> having extra LPF filtering was a good thing anyway.
> I would just leave the filter connected to the rig and forget about it.
> Paul, W9AC
73, Jerry, K0CQ
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