In a message dated 96-12-15 11:37:32 EST, you write:
>plate cap restores power output.
>Could it be the coil? By the time I get the cover off everything has cooled
>down!
>Could it be one of the doorknob caps slung across the plate cap (2x200
>pf@5kv on the plate which is 250 mmfd)? Perhaps one of the doorknobs across
>the loading cap?
It's the doorknobs drifting. They are not NPO (low drift) style capacitors,
The ITT Jennings are the worse ones, and HEC (High Energy Corp) are better.
Drift depends on the batch of clay they use to make the capacitors, and the
size of the cap. If you drop to values less than 200 pF, you can buy N750
caps. 200 on up, and you are stuck with N 3300. The lower the N number, the
less the drift.
Ameritron has N750 170 pF capacitors.You might get by with two of them. If
you are really stuck, I think I still have some batch selected 200 pF HEC
caps that drift less.
73 Tom
--
FAQ on WWW: http://www.contesting.com/topband.html
Submissions: topband@contesting.com
Administrative requests: topband-REQUEST@contesting.com
Sponsored by Akorn Access, Inc & KM9P
|