Well, you have 2 different animals listed. The FS-4 is a "solid state
adjustable "crystal"" accessory for the drake c line. Basic functional
testing could be done with a freq counter and scope. The best test would be
to plug it into a drake receiver and look at freq stability and noise by
tuning a known signal.

The FR-4 was a digital frequency display upgrade / plug-in built be Etek for
the drake c-line. This is basically a frequency counter with offset to
match the drake and packaged to complement the drake c lines. Inject a
frequency and compare input to displayed frequency for accuracy and
stability.

Still the best test is to plug it into a drake c transmitter or receiver.
Have fun-Don
wrote in message
oups.com...
Hi,

I just picked up a Drake FR-4 Frequency Synthesizer. I don't have any
Drake gear so can't tell if it works. Anyone know how to test it?

Thanks,

Jim