ORIGINAL MESSAGE:
On Mon, 24 Aug 2009 16:29:22 -0500, "Edwin Karl" <edk0kl@centurytel.net> wrote:
>The stray capacitance and the stray inductance coupled with the yeah many
>turns of whatever make a tuned circuit somewhere near 110 Mhz or so. Like
>magic the oscillation is tamed, there is joy and dancing in the streets.
>
>Having said all that, my purpose is NOT to stir the pot but actually help
>to end this silly dribble. In fact, someone back long ago (in a place
>far far away) came up with the traditional suppressor circuit. It works
>in thousands of amplifiers, and has worked for a long time.
>
>I really don't give a damm why it works or hearing long techno babble about
>it.
REPLY:
Here is a perfect example of the kind of misinformation this reflector can help
dispel. The parasitic suppressor DOES NOT " make a tuned circuit somewhere near
110 MHz or so". That tuned circuit is already there before the suppressor is
installed. Instead, the suppressor is there to reduce the Q of that circuit and
therefore the amplifier's gain at the VHF parasitic frequency. Reduce the gain
enough and the amplifier becomes stable.
When I read "I really don't give a damm why it works or hearing long techno
babble about it" I can only sigh. A ham with that attitude had best go to a
dealer and buy his appliance ready-made. Homebrewing is not for him.
73, Bill W6WRT
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