[TenTec] Ten Tec Omni-D Series B SWR Problem

[Dr. Gerald N. Johnson]

On Fri, 2008-04-18 at 12:38 -0400, Mike wrote:
> Well what is puzzling is that it only does it on 40 and 80 meters ssb, 
> 20,15,10 meters works fine...BUT when hooked up  into a dummy 
> load(Cantenna),Radio works fine too.I run other radios on my 40 and 80 
> meter antenna and they also work fine.Just the Omni-d has a issue with 
> my 40 and 80 meter antenna...

That's why I bring in the harmonics or parasitic oscillation. The tuned
antenna is frequency selective, while the dummy load is not frequency
selective. So there is an additional output to the spectrum that is not
on 40 or 80 meters where ever the antenna is tuned. So is reflected from
the tuned antenna and shows up as SWR. And the easiest spur to get is
harmonic from driving the PA too hard. Could also be a parasitic
oscillation or stray mixer product, but those ought to be as easily
triggered by continuous carrier. Just on SSB the voice is driving the PA
harder. Depending too much on ALC for drive control, try driving with
less audio to see if the SWR peaks are drive as drive sensitive as i
think they are.
> 
> Mike
> 
73, Jerry, K0CQ