[Amps] Minimum Value of RF Plate Chokes

[Edward Swynar]

On 26th February, Gary wrote:

"...Seems that with a small choke (small inductance for the frequency) the
choke is actually tuned to resonance when its reactance is a low value
compared to load impedance.
If the choke is too small for that band add extra input capacitance to the
tuned input network on the tube side to resonate the choke..."

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Hi Gary,

Many thanks for that FB explanation...however, in as much as it might make
sense to me, I STILL can't get past the notion in my head that I always
believed that a choke should be, essentially, "invisible" to the rest of the
circuitry that might accompany it...

By effectively changing the circuit values in a tank circuit to accommodate
a less-than-perfect choke, what is the fall-out going to be to the operating
parameters of the tube...? After all, we are now CHANGING computed values
for specific "Q" in the tank components, to make-up for the shortcomings of
the choke --- correct?

Also, what would happen when the final tank circuit is off-resonance
slightly --- will RF end-up back into the power supply?

Again, I may well be missing something critical here, but by having to go
through all these "gymnastics" in the values of the other parts of the
pi-tank system, it is very obvious that the presence of a "sub-standard"
choke is hardly "invisible" in the whole scheme of things, and it seems to
fly in the face of a properly-designed final pi-tank network, on a given
band...

Help me here...!

~73~ Eddy VE3CUI - VE3XZ