If the plate choke changes value how does it affect the plate tuning capacitor?
 

In the amplifier compartment of a 1970s vintage ham radio, if the
plate choke in the B+ supply lost some of it's inductance due to some
of the coil windings shorting together would it cause the plate tuning
capacitor to require less capacitance (such as fully open) to reach
resonance?

-Curios.

If the plate choke changes value how does it affect the plate tuning capacitor?
 

This is very strange... less inductance in the plate choke implies
less inductive reactance, thus needing a lower capacitive reactance
(MORE capacitance) in the "plate" capacitor.
Does the Tx perform well otherwise?. Or maybe you are fooled into
thinking you've found resonance, but it is at an harmonic or spurious
oscillation?.
If you've not done it yet, better replace that choke. Shorted turns
mean not only less inductance but also degrade the quality factor, may
introduce a significant power loss (and overheat too).
By the way, 2.5 mH is a common value, but 1 mH or less may be more
than adequate even for 80 m, and with less spurious resonances above
that. It is even better if honey-comb wound (less self capacitance) or
split in sections.

If the plate choke changes value how does it affect the plate tuning capacitor?
 

"Dante" wrote in message
...

In the amplifier compartment of a 1970s vintage ham radio, if the
plate choke in the B+ supply lost some of it's inductance due to some
of the coil windings shorting together would it cause the plate tuning
capacitor to require less capacitance (such as fully open) to reach
resonance?

-Curios.

Just an estimate...

I think the plate choke is effectively in parallel with
the plate tuning inductor. But, I suspect ratios between
the two inductances would preclude much interaction
unless there was a major loss failure in the choke.

I'd be more worried about parallel resonances in the
choke falling within the operating bands the amp covers.

If the plate choke changes value how does it affect the plate tuning capacitor?
 

"Dante" wrote in message
...

In the amplifier compartment of a 1970s vintage ham radio, if the
plate choke in the B+ supply lost some of it's inductance due to some
of the coil windings shorting together would it cause the plate tuning
capacitor to require less capacitance (such as fully open) to reach
resonance?

-Curios.


A couple of shorted turns would efect the inductnace of the coil a lot more
than you are probably thinking. My guess is that you are just aking how a
relatively small change inductance would effect the circuit and the answer
is none.

Jimmie