Hmmm,
"It suspect that they are talking about the Rp component as it relates
to the ohmic losses (read self-heating) of the choke. For Xp = 3000
ohms,
Rp would be well in excess of 200,000 ohms even for a modest unloaded
Q of 67. I am sure that is what they are talking about. At 200,000 ohms
(resistive) and 1900V rms anode swing, that would be 18 watts dissipated
in Rp. IOW, the equivalent circuit of the Z-7 choke would be something
like
3000 ohms reactance in parallel with 200,000 ohms resistive, where the
200,000 ohms represents the parallel equivalent of the series resistance
in the choke windings."
73 de Mike, W4EF
Just not true,
I'm looking at published charts here, where at parallel resonance 'fo'
(best situation), the choke exhibits more than 1 megohm effective
parallel resistance to the tank. Down at the lower freq. limit of
operation it still exhibits more than the 200,000 ohms. Nothing
mysterious, and I'm sure the 3000 ohms of reactance is in SERIES with
the resonant component (part of it). The use of resistance wire is news
to me, but if it's true, I don't think it affects the fo at all. R is
not even included as part of the L-C freq. equation. Besides, the slight
amount of series R introduced would be swamped by say, 50 ohms of
additional glitch resistor--I add this in response to your "concern"
about Ohmite's possible use of resistance wire. The DC resistance of
the choke is strictly limited by is dissipation rating.
73, Roy K6XK
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