Ham op wrote:

Cecil Moore wrote:

Ham op wrote:

What is the purpose of a 'swinging choke'?



To get it closer to the antenna feedpoint?


C'mon Cecil, you've been licensed long enough, at least as long as I
have, to know that a 'swinging choke' changes the center of percussion
on a baseball bat. It allows for a quicker swing. :-)

Now, if your antenna has a large capacitive component as part of it's
input ... then quite possibly a swinging choke might help.

But, if your HV power supply needs to limit inrush currents then ...

Back to my comment. I was interrupted as my XYL was leaving for work.

Seriously, for the younger ham reader. The older AM transmitters, vacuum
tube type, required continuous plate current at rated power. It was
necessary to keep full plate current even in the absence of audio. A
swinging choke, one with an critical inductance value that changed as a
function of 'DC' current [variable reluctance] , as the first component
of a HV supply, simplified the requirements on the other components of
the HV filter circuit. Namely, the first input capacitor. High power HV
supplies were typically designed using a double 'L' filter, choke input.
The first choke provided better performance if it had a variable
reactance as a function of rectified current. The minimum value of
reactance [critical inductance] was a feature of the 'swinging choke'.

Ah!! The good old days. Radios were radios that worked all tv sets,
stereos systems, and am broadcast receivers. I ran a 6AG7/6L6 at 10
watts on 15 meters CW and worked ALL tv sets [ALL] within 1/2 mile. I
used a good quality DRAKE LP filter, a Pi network tuner, and had very
low harmonic output and still worked all TV sets.

Question to the younger crowd ... Why did I have TVI?

Cecil, you should not answer. But, I suspect you had the same
experience. Note: Cecil and I both have formal technical training.