>>> Having designed commercial 800 MHz amps in the past, I prefer to have
>>> them stable (as much as possible) across all possible load conditions.
>>>
>? However, in uhf amplifiers the anode-resonance is the tank. In hf
>amplifiers there are usualy two resonant circuits connected to the anode.
Agreed. Still you can design an HF amp to be unconditionally stable and test
for that condition as well.
> .
>>And if it is with no drive applied and the
>>neon glows
>>orange it means it is oscillating on or near the band selected - not so?
>>
>? In my experiences, g-g triodes can occasionally oscillate in steady
>state without drive above the grid self-resonance. In a 3-500Z, this is
>approx. 80MHz.
Well, then those amps have design problems. Did those oscillations that you
mention from your experience occur with our without your nichrome suppressors?
In a well behaved amplifier you should see NO oscillation. That's why it's
called "well behaved."
Damn, it hate it when my oscillators amplify and my amplifiers oscillate! :-)
73,
Jon
KE9NA
--------------------------------------------------------------------------
Jon Ogden
jono@enteract.com
www.qsl.net/ke9na
"A life lived in fear is a life half lived."
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