[1000mp] Strange bahaviour on 80 meters

[Pete Smith]

At 10:46 AM 12/27/03 -0500, Joe Giacobello wrote:
>...
>However, even after Yaesu seemed to have solved the basic 15M SWR problem, 
>the SWR would unpredictably go haywire periodically.  Yaesu worked on it 
>again and concluded that the problem seemed to be associated with the amps 
>that I was driving at the time: a vintage 30S1 and a Viking 
>Thunderbolt.  When I replaced them with a TenTec Titan 425, my problems 
>disappeared...for the most part.  I say for the most part because every 
>now and then, totally without warning and for no obvious reason, the SWR 
>will go haywire.

I haven't had the transient SWR problem with my Mark V, but after I 
modified my SB-220 for QSK, I discovered that my TS-930 didn't want to 
drive it without the tuner engaged on 10M.  Later, I got the Mark V, and 
discovered a similar problem with the drive on 40M, which again was cured 
by setting a single tuner memory and letting the radio extrapolate from 
there.  It was fine on 10; in neither case did the input SWR look THAT bad.

I think Tom Rauch and others have commented that these older amplifiers 
that were designed for tube exciters with adjustable pi networks can be 
quite cranky with newer solid-state rigs, depending on a lot of design 
variables.  I once tried to substitute a much shorter input cable, and my 
TS-930 didn't like at AT ALL.


73, Pete N4ZR
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