Wow this amp project has gotten enough input to build
a dozen or so amps. Lots of good info, some BS as
These discussions make me happy I am retired for one
thing, dont have to do this for a living any more. hi hi
I run several 4-1000 amps here for the past 30 years,
they say it cant be done thats BS.. mine operate 160
through 10 meters, full out put on all bands. At 5KV
I can load to 800 ma no problem, out put on a bird is
over 2500 all bands. No I dont use a B&W coil, they
suck with a 4-1000. just use home wound copper tube
and wire for 160 meter coil. input network is a pi-net.
Fooled with the other types of circuits and never could
get a broadbanded 1 to 1 match across the bands.
Use toroids and trimmers for the inputs, they work just
fine. If you go 160 to 10 a shorting bandswitch is the
only way to go. Cures many of those fireballs so common
with 4-1000 amps. I dont ground to grids directly either
they are grounded through a low value wirewound resistor
and the resistor bypassed with several disc ceramics.
The parasitic plate lead is 3 turns nr 12 wire 1inch diameter
with no resistors across it. Extremely stable amps and
run all day long on RTTY at full bore,(with big enough blower).
So no I dont know all the formulas, dont know the Q of the
input circuit, the tank circuit uses little over a PF per meter
as the oldtimers used to say. Vacuum variable C1 and
air variable on the output.. RJ1A output relay and reed
relay on the rf input. Design engineer I am not, but at least
mine works. 73 Merv K9FD
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