--- ad5gb <ad5gb@myway.com> wrote:
> Therefore, I'm curious to know if there are others
> on this reflector who've experienced similar problems (any brand
> amplifier) that have been successfully solved with the AG6K ( or
> another design ) VHF supressor. To round out the study, one would
> also need to know if someone had installed such a thing and found
> that it *did not* solve the problem it was intended to correct, or if
> it caused other problems.
>
I'm glad someone finally asked a question like this. I'm curious of
the results as well. Here's my story:
Bought a used TL-922 with the 10m mod already installed. Fired it up
and got full output, but about 15 minutes after testing, the amp made a
horrible buzzing noise, blew one of the mains fuses, and let out a puff
of smoke. Found the welds bad in both Eimac 3-500s. By the way, it
defintely arced on tune-up. The antennas are a resonant Alpha-Delta
40/75m dipole and a Gap Titan. SWR is NEVER worse than 2:1. Feed line
is new RG-213, no lightning arrestors. Everything is grounded.
Bought a matched set of RF Parts 3-500ZGs and the amp still arced on
tune-up. Installed the extra capacitors and grid-fuse resistor, along
with home-brewed Rich Measures suppressors. The amp hasn't arced,
spit, or sputtered on tune up since. I still need to add the
step-start, but just haven't had the time. Also have a new bandswitch
(that I haven't installed yet) since the original has carbon tracks on
it. I also installed the filiment mod -- I have pretty high line
voltage so the filiments were getting almost 6V. They're now down
around the recommended 5V. I also want to install the fast (and quiet)
switching mod.
Bottom line, the mods fixed the arcing, and I spent less than $3.00.
I'd like to ask Tom why these work -- he seems only to say that
parasitics don't exist, and the mods don't make sense. If that's the
case, why is my amp now working so much better? The filiment mod is
very clear to me, same with the step-start mod. Why is this such a big
deal? If you make your own suppressors, you'll spend very little, and
certainly won't hurt anything.
Also, if parasitics don't exist or are "Voodoo", why are there
suppressors on just about every amp or tube transmitter??
73,
Joe - N3JI
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