John is correct. But - it can be checked before operating with a
Grid Dip Oscillator (Or the FET version).
With the GDO coil next to the windings of the rf choke, and the
coils running the same way, tune through all of the spectrum and
make notes of all of the dips. There should be several. If any fall next
to, or within one of the amateur bands, you'll have to do some mods.
By the way - the choke must be in the circuit to do this, as resonant
points will change if you remove it.
I make all of my own chokes, and sometimes I get lucky, sometimes not!
de KL7HF
John Brosnahan wrote:
>
> One word of caution on using "old amplifiers" (pre-WARC designs)
> on 12 meters. Most old amplifiers used a plate RF choke with
> a series resonance near 24-25 MHz. Operating one of these amps
> on 12 meters is very likely to result in offensive smoke in the shack.
> Recommended testing date for these onld amps is Independence Day,
> you will enjoy the fireworks display!
>
> 73 John W0UN
>
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