Dick,
Hear, hear! Good response!
> I've watched this reflector for some time in silence but now find a
>question that seems to need to be asked....
>
> What is it about amplifier parasitics that is so foreign to so many
>experienced amplifier people here?
Parasitics are tough to trace and not easily seen.
>
> I think Rich Measures is to be commended for his extensive
>investigative work into this phenomena whether or not he is totally
>correct in every aspect of VHF parasitics.
The biggest thing Rich does is start discussions. I am studying Rich's
theories and while I can't say that I totally agree with him, I can't say
that his ideas are without merit either. The fields of science and
technology only move forward due to debate. Aristotle and Ptolemy had
incorrect ideas about the revolution of the planets around the sun
(earth-centered universe). However, we don't deny that these men were
great philosophers and scientists for their days. Galileo was called a
sorcerer, yet today we owe a lot to his "sorcery."
The Ludites in England threw their shoes into the automation machinery
during the industrial era. The Ludites today are those people who refuse
to look at any other viewpoint just because "this is the way we have
always done it this way before." In my days in engineering I have seen
many "Ludites." And I am not talking just the ham radio crowd either.
So Rich may not be completely correct. Big deal. But I bet no one's
amplifier has been destroyed by his supressors. The first person that
told me about Rich said that his supressors tamed his untamable amp.
To lambast someone's theories without having a theory of your own is just
ad-hominem attacks. To say something doesn't work just because you
"don't think so." Is not disproof of a theory. So far, I only see Rich
putting forth any new ideas in the parasitic field. Everyone else
laughs. Yet no one has better ideas. And Rich is willing to be proven
wrong.
It may sound like I am an AG6K loyalist. I'm not. I'm just pointing out
that to criticize a person without any facts is hogwash. I've seen some
people do that.
> I have a stock original-tubed
>full-output MLA2500 that has never, in the dozen years I have owned it,
>showed any tendency to selfoscillate. I can see that this fact doesn't
>mean such will always be the case. Some circuit parameters can change
>with aging alone. I believe that a few bucks spent on prevention could
>be very cost effective in avoiding the expense of a set of new tubes.
>Whether it "needs" it or not.
Oscillation can depend on tube gain, component placement, aging, etc.
Something could happen in the future.
An ounce of prevention is worth a pound of cure.
73,
Jon
KE9NA
-------------------------------------
Jon Ogden
KE9NA
http://www.qsl.net/ke9na
"A life lived in fear is a life half lived."
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