I don't know if you can help with this in the forum but here goes; My plane is a Wittman Buttercup with the first series Lyc. 0-235, probably never intended to be in front of a radio. P leads are shielded except for a few inches were they connect to the mags. I have an wire external antenna. I had been using handheld radio going thru outside antenna. Seemed to work but but a pain to handle. So - I installed an old Collins Com radio on top of the dash and wired it all up with PTT and headphones. Its a better setup but - receive is loud and clear, Xmit light lights and there is garbled, staticy transmission and people can't understand me. I just re-routed the shielded antenna lead away from the inside firewall but no improvement. Suggestions for what to try next?? Thank you.