Dear subscribers,

My com radio is not working as it should. In some areas it is working perfect. In other areas it does not work well. It seems to be worse at high altitude/high speeds and along the shore lines or over the great lakes. It is possible that I can barely read the controller and 20 miles further it is decent. On the ground or around an airport it always works ok. Sometimes I get a lot of static noise (depending on the airport). Sometimes the controller sounds like he would talk out of an helicopter. I am using the bose head sets.

I have metallic paint. I got static wicks – all grounded well. I got a Garmin GNS530W, a Garmin GNC250XL and a Garmin GMA340 Com Panel (see pic)

I got the following antennas:

-          VOR (in the fiberglass wing tip internally) – never had an issue

-          transponder (wing root externally) – never had an issue

-          marker (externally under the 0 of the N# - see pic) – never had an issue

-          GPS1 (internally in vertical stab. ) works ok – if I do two rolls in a row the GPS loses signal – other than that no issues

-          GPS2 (internally in vertical stab.) works fine

-          COM (internally in vertical stab.) – I don’t know exactly where it is (was already in when I got the plane) but I get the cable out of the vert. stab. so I guess it must be in there somewhere.

The COM antenna gets split with a duplexer for the GPS1 and GPS2 COM input

I assume that my radio problems are related to the metallic paint and the carbon bottom of the tail /elevator the shield the antenna please tell me if you have a different opinion.

All my antenna cables are split at a little interface plate behind the panel (see pic). It is fairly easy to disconnect and reconnect the cables.

My plan of action is (please feel free to tell me if I am talking nonsense)

-          Remove the marker antenna on the belly (I never use the marker signal on an ILS, I monitor the GPS 530 for my location and distance to way points, I would not notice if I lose this function)

-          Place an external COM antenna at the location of the marker antenna (I got about 1sqft of aluminum shield on the inside of the plane there - I would need a recommendation for which antenna to pick)

-          Reconnect the antenna cables at my interface plate: COM1 uses new external COM antenna (old marker antenna), COM2 uses existing internal antenna, the marker would have no antenna anymore

-          I would leave the duplexer in there for now and use only one output for the COM2 – I would remove the duplexer later it everything works fine

-          The COM1 input would be connected directly to the antenna without the duplexer

Thanks for your help

Ralf