Hi KRS,
-
I have a similar setup, the 10m cap value worked out
to be well less than 45pf, often using less than 7pf tune
C. Since the tube has a high Cout, conventional circuits
don't work with tune caps that have a substantial
min C values.
-
Change the cap out or try a different tank design.
I ended up making my own tune cap from a
surplus disc unit (was an ex neutralizing cap
removed from an old GE VHF Low band broadcast
KPOO transmitter I found in an elevator shaft in SF).
It's min C was less than 3pf when "backed out."
-
I have some vacuum variables which drop to less
thank 5pf, but they are hard to find. Another approach
would be to use the ARRL 6m Handbook method of
years past which has a squeeze tune variable L, fixed
tube Cout with no variable tune C.
-
cheers
skipp
-
Current music CD "choice" recommendation: Artist - Dido, Tittle - no
angel
-
http://sonic.ucdavis.edu
-
[snip}
I need some advice from the experts. I have a recently brought back to
life
GG 3cx3000a7. Its running on a higher plate voltage, approximately
6700KV.
When tuning up on 10 meters with a TS 440 into a dummy load, with
approximately 70 watts drive I am only seeing 200 watts on the Bird.
What's
odd is the Jennings 10-370pf plate tuner is backed all the way out to the
minimum capacitance and that's where It tunes for max output. I thought
it
would tune around at least 25pf but its backed all the way out. What
should
I expect to see with say 100 watts input provided tank is right?
KRS
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