[AMPS] Tune Up of Henry Amplifiers, Prt. 2 of 3 parts

[Jim Reid]

Part 1 concluded with an offer to send images of Henry Ultra
amp presets along to anyone interested.  Continuing now:

My 24 presets are set up now for eight of our H.F. bands,  none
on 30 meters;  200 watt max limit there.  But have them beginning
with a couple on 160 and on up to 10 meters.  But they have been
set up by fiddling with the tune and load only looking for 1500 watts
out,  CW (but using the SSB or higher plate voltage switch position
which is about 6000 volts, key up) and adjusting "tune" first(the tune
control is a Jennings vacuum variable at the "pie" circuit output),  then
the "load" pot(which controls two rotary inductor positions,
simultaneously,  the "pie" inductor and the output dangling network
inductor),  then touch up for minimum input drive to yield the desired
1500 watts out.  Of course,  this differs for each band.

The Henry 8K output circuit is a pie plus the series inductor
to the antenna feed line(the dangling inductor).

Now, must I go back and redo
all 24 presets again watching for the plate current dip,  and check
for the 1:3 grid current.  That seems high to me.  Not sure how the
Henry output network fits in the previous excellent discussion by the
others,  but gather Peter does not agree that the grid current
ought to be max,   at around 1/3 of the plate current.

Note here:  Peter has read this info sent to him direct and responds
that I misunderstood his earlier quote,  or perhaps I quoted not
completely enough.  Anyway,  here is Peters response to my
post directly to him:

"Jim says:

>Not sure how the Pi-L output network fits in the previous excellent
discussion >by the others,  but gather Peter does not agree that the grid
current ought to >be max,   at around 1/3 of the plate current.

Slight mis quote here; I was only talking about resonance, not necessarily
what you tune for - I'm a believer in the 'maximum smoke' approach, and then
load a bit more heavily.

Good interesting info.

73

Peter G3RZP"

End of this inserted note,  and the end of part 2 of
this three part note.

73,  Jim,  KH7M



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