Dan/W4NTI wrote:
I am thinking of building up a single ended 4-400A for six. Mainly cuz I've
got a old homebrew HF amp with a good bit of the "stuff" I need to do it
with.

I wonder (since I'm a bit rusty these days), if I can Grid Drive it? I will
only have a basic transverter output (8Watts) available.

Anyone point me to a site or material about the input and output circuitry
needed?

Any thoughts?

Dan/W4NTI


If you run the tube in class AB1 it won't need ANY driving power, just
voltage. So with the right input network your 8w exciter should do the
job. You WILL need to neutralize the 4-400A at 6 meters. At this
frequency the tube is below it's self neutralization frequency, so
a conventional neutralization network will work. (above the self
neutralization frequency you have to resort to tricks such as series
tuning of the screen leads).

There was an QST article some years back using a 3-500z on 6 meters.
The tank circuit used a copper tubing coil with a rotating shorted turn
for tuning instead of a variable capacitor. However a Pi network can
work on 6, though you might have to use a 'dual disk' capacitor and
tap the tuning cap down on the tank coil.

BTW the 4-400 is good for use up to about 110mhz.