Why do you need a good bandswitch to prevent arcing at high voltages?
The band switch should come AFTER the DC blocking cap. Therefore, as long
as it can handle the circulating currents present in the tank, the plate
voltage should make no difference.
If you have a design that is not DC blocked (not sure why you'd want to do
that), then I agree. But with a proper design, it should not matter.
Also, no offense to Mike, W1NR, below, but I suspect his power numbers as
well. All my experience and actually data in the books shows that the
4-1000A does not put out 1800 W from 100 W in at 4400 Volts. Perhaps he's
got an extremely hot tube, but that is not the norm.
Most ham power meters are not at all accurate at mid-scale power readings.
73,
Jon
NA9D
on 4/3/01 5:48 PM, DF3KV@aol.com at DF3KV@aol.com wrote:
> That is exactly my experience wirth QB5/1750 or the russian aquivalent.
> 12-13db of gain are quite normal with 4,5 to 5 KV on the Plates in
> GG zero bias configuration.
> With higher voltages you need a very good bandswitch to prevent arcing.
>
> 73, Peter
>
>
>
>
> My 4-1000A amp will get 1800W key down output with 4400V full load
> on the plate and 100W drive. At 5000V things start to arc all over
> the place. It is very happy with 70W drive for 1500W output and 4400V
> full load plate voltage. Tube is "new old stock", not a BC pull.
>
> Mike, W1NR
-------------------------------------
Jon Ogden
NA9D (ex: KE9NA)
Member: ARRL, AMSAT, DXCC, NRA
http://www.qsl.net/ke9na
"A life lived in fear is a life half lived."
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