To: <amps@contesting.com>
> Date: Mon, 01 Jun 1998 10:42:45 -0600
> From: "Richard W. Ehrhorn" <w4eto@rmii.com>
Hi Dick,
> If your plate choke were absorbing even 100W I believe it would quickly
> become hot enough to smoke.
The problem isn't one of absorbing power right *at* resonance, that
almost always only occurs when the choke is only very *near*
resonance... or if the choke Q is so low the choke doesn't look
nearly like a "dead short" compared to the time averaged resistance
of the anode.
If the choke is an almost perfect series resonant short compared to
the time-averaged anode resistance, the anode voltage of the tube
won't swing at all and the choke heating will be very minor compared
to tube heating. The tank can't see any power because its input
capacitor is effectively shorted by the choke.
> Another possibility - maybe - a choke impedance
> consisting of a low value of effective series reactance and also relatively
> low effective series resistance (i.e., near a high Q series resonance?) at
> your op freq could CONCEIVABLY make it impossible to tune the tank close
> enough to get significant output.
Right. Another way of saying the same thing. The anode can't move,
and the tank can't tune.
> This is pure speculation; I don't recall having seen such a situation,
> where the choke screwed up tuning but didn't overheat. But it seems
> conceivable. Ian? Tom? John? Carl? Anybody experienced this?
Yep.
73, Tom W8JI
w8ji.tom@MCIONE.com
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