[R-390] R-392 tube oscillation

[Robert Newberry]

When I fire up my R-392 I've noticed in the 80m band I get what appears to
be some tube oscillation. It is very sharp and tuning + - it goes away.
After the set warms up its not so much of an issue although its still
prevalent below 3.500 mhz and above 3.200 mhz.

I haven't tried pulling tubes and swapping yet. Figured I'd see if there
are any tips. I also need to locate more tubes.