[R-390] R-390 alignment questions

[John KA1XC]

> I thought I would go back and input a signal on the balanced input through
> two 68 ohm resistors and set the balance trimmer for each band only to
find
> the radio pretty much deaf.

Cecil,
for doing the balance adjustment that's perfectly normal. I've found that to
get a hearable signal for nulling I need to set the generator output several
orders of magnitude greater. (Think about it, if the input balance was
perfect you'd never hear ANY common mode signal).

RF alignment is best done using the low-z balanced input with one side
grounded (thus making it unbalanced) and connected directly to the signal
generator output. Connecting a 50 ohm sig gen output to the hi-z unbalanced
input will work of course but you're *really* loading down the front end
tuned circuit and probably getting a much broader peak during its alignment.

John