My Garmin GNC-255A Nav/Com has static

[Steve Schroeder]

I have a SportCruiser with Dynon HDX and a Garmin GNC-255A Nav/Com.  I'm having an intermittent problem with my Nav/Com where the automatic squelch breaks with lots of static. Sometimes it happens all by itself and other times it seems to be related to when I'm using the touchscreen on the Dynon HDX. It seems to happen most in the 119.3 frequency range which happens to be the tower frequency at my home airport at Van Nuys.   I called the shop that did the avionics install and they thought it might be a bad antenna cable.  I did a temporary swap with a new cable and I  still experienced the problem.  I'm in Los Angeles and the avionics shop is in Texas so I'm trying to troubleshoot it myself. I have heard bad grounds in avionics will cause these types of problems but I don's see anything loose.  Just looking for any suggestions.  I tried a couple local avionics shops but they're all jammed up with ADSB installs at the moment. Thanks

[Blueyonder]

Hi Steve.

That seems to be a somewhat common problem, I know of one in FUL that has HDXs and GTR 225, that exhibits a similar problem. Did you try to slightly tap on top of your instrument panel dash, that seems to temporarily stop that Rx signal, and see if it helps?

The only thing you can try is to find someone that has a similar radio, that fits your harness and try it in your plane, make sure you do not do anything that is outside the rules of your  owner's rules.

I read somewhere about another radio SL30? where there was an SB about the distance between the antenna and the HDX cables that may affect it. You could be dealing with similar issues. I do not think the 225 is the same pin configuration but you may find others that have the Make/  model.

If you want to continue the discussion, you can send me a private Email, you seem to be close to FUL and we may be able to exchange further details.