Mike,
I wonder if you have changed the jumper between the transceiver and
the amp. Perhaps it is some odd length that is causing trouble on
twenty. I seriously doubt that you are having tube problems with the
amp - if so, as has been pointed out, output on ten and fifteen would
be low as well. And I think that your friend is making a good faith
effort on your behalf and perhaps has just missed the actual
problem. I have a pretty good handle on at least the older gear but
have made some incorrect diagnoses in my ham lifetime. Doesn't make
me an idiot - makes me a bit more careful the next time!
Good luck.
Pat, K9JAUAt 09:34 PM 4/6/2014, you wrote:
>Hi all:
>
>I know this discussion has been posted to the list many times but I
>wanted to gauge an opinion again.
>Does anyone know if an Unun fed antenna, mainly a vertical, induce
>high currents and voltages back through a coax feed line?
>I'm getting an indication that my 43 foot vertical is now the cause
>of my apparent tube failure and if don't stop using it, I'll blow
>the crap out of the rest of my station.
>My own tuner, after a period of a couple of months of use, started
>having trouble tuning out a 75M 6/1SWR spike but behaved perfectly
>on 40/10, including the DX contest with my amp running 600W CW with
>50W of drive.
>The tuner I have now, handles this antenna from 75M to 10, didn't
>try 160, with my amps 600W CW no problem. My own tuner, is currently
>on a wire antenna, handling the SSB output from a HeathKit SB-220,
>about 1200W, 75/10M with no problems.
>Put my tuner on my antenna, it will tune perfectly and handle 200W
>on 75/10M but put 500W CW through it, the amp hissed. This may have
>lead to the 20M issue a couple of weeks ago but I don't think my amp
>is made of cardboard. LOL
>Now how would a trapped vertical be different?
>I'm very confused, discouraged and most of all scared.
>I don't know what's to gain by BSing me but its starting to look
>like the gentleman who's been a helping friend since I got my
>license is doing just that or is simply wrong.
>
>73:
>Mike VO1AX
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