Comm Noise

johnfurey · #1 08-01-2011, 03:57 PM

I have an SL30 and a GMA240 in my RV7. Some times the controller says that I am Loud and Clear and other times that there is a lot of background noise. I can hear the difference in noise level in the sidetone also. I have never had this issue with any other plane. Any idea why this is happening? Is there any adjustment in the SL30 that would help?

tkatc · #2 08-01-2011, 04:18 PM

I do not have an SL30 but I had a similar issue with my Icom A200. I have tried turning down my MIC gain which seemed to help a bit but I think what worked for me was changing to a headset where the MIC wasn't so sensitive. I was using a QT Halo but switched to a Bose X to eliminate possible headset error. It didn't help but when I switched to a Clarity Aloft headset it was like night and day. Still slightly rough but a marked improvement. I recently purchased a "mic muff" from Oregon Aero in hopes to further reduce backround noise but have yet to communicate with my fellow controllers who are used to hearing my "old" transmissions. I suspect it will be even better.

Bill.Peyton · #3 08-01-2011, 07:27 PM

Assuming that the radio is OK. The background noise is usually from a defective noise cancellation element in the mic. Try someone elses headset and mic. Also, I have found that the mic muff can make a huge difference.

Walt · #4 08-01-2011, 07:36 PM

I use a mic muff and clarity headsets with my SL40, works great! The mic muffs do help.

johnfurey · #5 08-01-2011, 07:46 PM

I will try another headset. I have a Bose and a Clarity. In all other planes the Clarity is hands down better in all areas but in this plane it is far worse

Bill.Peyton · #6 08-02-2011, 07:20 AM

What kind of noise do you have? If it is cockpit wind noise then it is the mic/headset, if it is whining, buzzing, etc, then it may be a wiring issue. The headset jacks must be isolated from the metal frame they are mounted to. The installation calls for single point grounds, which means the headset end ground (shield) has to be isolated from ground. The jacks are usually mounted with insulating washers.

johnfurey · #7 08-02-2011, 07:30 AM

It seems to be cockpit noise. I do not detect any static, whine, cracking, etc. This plane has a tip up and I do not have the firewall or side panels insulated yet but I would not think this plane is that much louder than my previous 2 with a slider???

Bill.Peyton · #8 08-02-2011, 07:44 AM

Wind hitting the mic will cause havoc, using a muff with help with that. Take off the headset in flight and listen to see if you have a large leak and how high the noise level is. A good noise canceling mic should eliminate most all the noise except wind blowing directly on the mic. I had a pair of Flightcom Denali ANR headsets that were terrible until I installed the mic muffs.

trib · #9 08-02-2011, 09:50 AM

This may sound simple, but the best solutions often are. I get high background noise when talking on the radio if my vents are aimed more or less directly at me. When this happens, I simply turn them outboard so the air more or less swirls around the cabin instead of blowing right at me. Sort of obvious, so you may already do this, but figured I'd point it out.

I do have a mic muff, so although it may help, I still get excessive noise in this condition.

johnfurey · #10 08-02-2011, 10:49 AM

I thought the vents were part of the problem also so I shut them off totally with little change.