Anyone have an Xcom radio and have limited reception?

Recently flew a RANS S-7 from MN to Oregon and the radio didn't seem to have a lot of range, especially when it came to receiving tower responses. The antenna is mounted on a flat piece of aluminum behind the baggage area. My thinking it the grounding may not be enough since this plate is mounted via adel clamps. My suggestion to the owner was to put a grounding strap from this plate to the fuselage. I did mention that the place it is grounded to need the powder coating removed for the best contact.

Has anyone else used this brand of radio and had this issue?

Thanks!

I have an xcom in my Acrosport and it works very well. Nothing like the issue you described.

I don’t think a ground plane like you’re describing needs an electrical ground connection to the airframe. I would suspect issues with grounding and adequate power for the radio unit itself, and possibly poor connections for the antenna coax.

Thanks guys!
Zzzz, what you suggest is basically what I relayed to the owner to check. He may have to take it to a radio shop.