>Rich says:
>
>>? A vhf suppressor partly de-Qs the anode-resonance by stagger-tuning
>>it. This is accomplished by having two current paths of differing L, by
>>aiming the two electromagnetic fields 90-degrees apart, and by causing
>>roughly equal vhf current to flow in R-sup and L-sup. Naturally the
>>differing L requirement depends on there being a substantial lack of
>>inductance in R-sup.
>
>Sorry, Rich, I totally disagree.
>
>The parasitic suppressor works by increasing inductance in the plate circuit
>until the plate parasitic resonant frequency is lower than the grid
>parasitic resonant frequency. See Terman's 'Radio Engineering'.
? page number?
>So parasitics can be suppressed purely by adding inductance. It's often easier
>however, to not pull the plate circuit that far LF, but to reduce the
>dynamic impedance of the plate parasitic suppressor by adding resistance as
>well tuning the plate parasitic resonance lower.
>
? In a typical 3-500Z vhf-suppressor, R-sup has 10nH of L and L-sup has
100nH. Are you saying that less L in R-sup tunes the anode resonance
lower in freq.?
>There is only one parasitic plate resonant circuit.
>
? Are you saying that it is impossible to create a broader resonance
with one capacitor and two inductors that have different amounts of L,
that are not mutually-coupled?
>It does not get shocked into oscillation by switching the bias unless the
>resonance is above or very close to above, the grid VHF parasitic resonance.
? In the 922, the grid resonance is c. 90MHz, and the anode resonance is
c. 130MHz.
>If it can be so easily shocked, why do you not see non-harmonically related
>outputs from all amplifiers?
? The damped-wave VHF ringing in the anode circuit can not pass through
the lowpass tank. To see anode-resonance ringing, the spectrum analyzer
is somewhat-gingerly coupled to the anode with some sort of hi-pass
arrangement.
> After all, an amp or so of pulse plate current
>every 71.43 nanoseconds (i.e. the fundamental plate current pulse when
>operating on 14 MHz) should shock excite this VHF circuit much better than a
>200mA pulse every 40 milliseconds or so from an el bug sending dits.
>
? I have not measured the rise times. However, big-bangs in 922s have
reportedly happened both ways.
>
- cheers, Peter
Rich...
R. L. Measures, 805-386-3734, AG6K, www.vcnet.com/measures
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