Your trim indicator signal is either at a D C level, or at a low audio frequency. The radio frequency is much higher, and is being rectified to a D C signal at the input of the indicator.
I would suggest that you put a 0.01 microfarad disc capacitor across the input wires. It will bypass the high r f signals, but would not affect the trim signal. I used this technique to tame my Tiny Tach that was picking up hash and reading about four times too high. Jim Vance N 303 JV at the airport Claflin, Kansas va...@hbcomm.net
