Hal,
You raise a good point which could be extrapolated like this: Parasitic
oscillation MAY be the cause for SOME grid-to-filament shorts. There has
been equal number of situations where the application of Rich's nichrome
wire suppressors eliminated the problem as well as not. I don't think there
is a person who subscribes to this list that can say with any certainty that
one case out weighs the other. Simply because we don't know all the forces
at work at that time.
The one instance I used them, they worked fine and solved the issues,
(I didn't get them from Rich but bought the wire from another vendor). I
know of several other local hams that have used them and it cured the "tube
eating" amp. But, there are others here that claim that they didn't help one
iota. So its a wash.
So far there hasn't been anything concrete offered up by anyone here to
convince me that it does nothing to/for the amp. Expert or not! Just my
opinion from my corner of the solar system, (which BTW Pluto is still a
planet in).
Mod-U-Lator,
Mike(y)
W3SLK
----- Original Message -----
From: "Harold Mandel" <ka1xo@juno.com>
To: <AMPS@CONTESTING.COM>
Sent: Saturday, August 26, 2006 3:00 PM
Subject: [Amps] Parasitics & Filament Sag
Gentlemen,
A previous post mentions a phenomenon wherein is written
"parasitic oscillation" and what I deduce as filament sag.
Is it possible that these two conditions are related?
It is understood how a strong magnetic field within the tube envelope
can perhaps alter the filament geometry, but can this happen as a result
of a VHF "excursion?"
Respectfully,
Hal Mandel
W4HBM
[SNIP]
> Hundreds of empirical observations from all makes of amplifiers must be
> wrong. Clearly, the problems must be the mysterious parasitic
> oscillation, which obviously is pushing the filament sideways.
[SNIP]
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