Biplanephil
New member
I have a 2000 7GCBC. I have an intermittent radio reception problem. The reception itself seems clear but it is overshadowed by a crackling in the background that can make the reception difficult to understand all the way up to being unreadable. It can be present at the onset or sometimes it doesn’t happen for 30 minutes up to an hour. And I’ve had times where ATC is garbled, asking them to repeat, only to have their next transmission clear. My transmissions however are always clear. I have a Garmin 430W nav/comm, a Garmin GMA 345 audio panel and a Bendix King KT76 transponder.
I’ve owned the plane for 2 years. The radio worked fine at first, it was until 3 months passed that I started noticing the issue, minimal at first and gradually getting worse. Looking back I find it interesting that there are noise suppressors on the mags and per ACA the plane did not come from the factory that way, but I can’t find any logbook entries.
My suspicion is I’m picking up noise from the engine or wiring. One reason I suspect this is when I shut the engine off the noise problem goes away and my reception is clear.
The GMA 345 audio panel as well as associated wiring is new, one of the attempted fixes, to no avail. I replaced the 430 with a loaner unit and the problem remained. I’ve done a variety of fixes all to no avail. I had wiring checked and inspected as well as grounding planes. I added a noise suppressor to the alternator. I took the alternator out by removing the belt. I replaced the spark plugs as well as the ignition harness. Most recently I changed out the coils and capacitors in the mags.
I’ve worked with my FBO the ones who do my maintenance. I’ve had the plane inspected by two different avionics shops. I’ve talked to American Champion as well as Garmin. I’m frustrated and at a loss. Any insight would be greatly appreciated.
Cheers,
Phil
I’ve owned the plane for 2 years. The radio worked fine at first, it was until 3 months passed that I started noticing the issue, minimal at first and gradually getting worse. Looking back I find it interesting that there are noise suppressors on the mags and per ACA the plane did not come from the factory that way, but I can’t find any logbook entries.
My suspicion is I’m picking up noise from the engine or wiring. One reason I suspect this is when I shut the engine off the noise problem goes away and my reception is clear.
The GMA 345 audio panel as well as associated wiring is new, one of the attempted fixes, to no avail. I replaced the 430 with a loaner unit and the problem remained. I’ve done a variety of fixes all to no avail. I had wiring checked and inspected as well as grounding planes. I added a noise suppressor to the alternator. I took the alternator out by removing the belt. I replaced the spark plugs as well as the ignition harness. Most recently I changed out the coils and capacitors in the mags.
I’ve worked with my FBO the ones who do my maintenance. I’ve had the plane inspected by two different avionics shops. I’ve talked to American Champion as well as Garmin. I’m frustrated and at a loss. Any insight would be greatly appreciated.
Cheers,
Phil