LF: Who stole the amps?

["Tom Boucher" <tom@telemetry.demon.co.uk>]

Ian

A pretty obvious point really, but are you sure the output power of your
amplifier is not varying due to impedance changes as you alter the
grounding? i.e. A mismatch is causing output power to drop.

I had some very strange effects when I used to tune for maximum current
instead of matching to 50 ohms. Now I have a 50 ohm SWR bridge from the
Tx LPF and this goes to a simple series loading variometer. Results are
a lot more predictable and I haven't blown a FET in about 2 years!

73, Tom G3OLB