Roger Lee Posted September 27, 2010 Report Share Posted September 27, 2010 Excessive VHF Radio noise at take off and cruise RPM This problem relates to noise that is heard on transmit in your headphones via a function called side tone, which allows the pilot to hear, monitor his voice as he speaks. The side tone is produced by your SL30 or SL40 radio. My LS had this excessive noise at take off and higher cruise RPM but was fine during taxi calls and tolerable at lower RPM during circuit communications etc. The noise successfully resisted all concerted attempts and all known remedies, like faulty earth connections on electrical buses, connectors, capacitor, auxiliary audio input, faulty insulation washers, you name it and it was checked or replaced or tightened. As this was a new LS, I was somewhat uneasy about the fixes attempted and the even more so by the results which amounted all to NIL. The solution came to me after I removed the noise cancelling headphones in flight and quickly putting them on again because of the noise level in the LS is a lot louder to what I had been flying previously. The default settings in the SL30 have been set to cabins with far less noise than an LS. As a result the side tone levels have to be adjusted and this is accomplished by putting the SL30 in to system mode, rotate the large knob to COM option page, press ENT. Rotate large knob select “side tone”. Mine was set to a value of 50 out of 100, which was too high. You turn the small knob to adjust the value 1 to 100. I turned mine past 1 which brings up “variable” and slaves the side tone to the volume control and worked just fine with my SL30 and FD CTLS. The objectionable noise is gone. Hope this helps somebody else.You will find this procedure in the "SL30 nav com pilots guide page 32". I suspect the SL40 is very similar, consult your manual. Happy flying! Niels Link to comment Share on other sites More sharing options...
N78BZ Posted September 27, 2010 Report Share Posted September 27, 2010 This is great. I've had that problem but never poked around looking for a solution. As soon as my SL30 comes back from Garmin, I'll give it a try. Thanks! Link to comment Share on other sites More sharing options...
Tip Posted September 27, 2010 Report Share Posted September 27, 2010 I also have had issues, and didn't know that the SL 40 had adjustable setting. Great information! Link to comment Share on other sites More sharing options...
S3flyer Posted September 28, 2010 Report Share Posted September 28, 2010 Thanks, Roger! Made a BIG difference today. One minor correction -- the value ranges from 0-255. Mine was set at 238 and is now at 0. Link to comment Share on other sites More sharing options...
Patrnflyr Posted October 5, 2010 Report Share Posted October 5, 2010 I tried to do this on my SL40 but couldn't tell much of a difference. Maybe I'm doing something wrong or don't know what to look for. Will try it again on the way to Page. Is there a way to try it out while you're transmitting to hear it as you adjust? John Link to comment Share on other sites More sharing options...
flyerg1000 Posted October 2, 2011 Report Share Posted October 2, 2011 Hello Roger, The heading GL30-GL40 for Radio noise fix should perhaps read SL30 and SL40, read the text posted by myself originally and re posted here. With my complete blessings of course for the benefit of all CTfliers. Niels CTLS VH-NKO Link to comment Share on other sites More sharing options...
207WF Posted October 7, 2011 Report Share Posted October 7, 2011 My SL30 has a system button where one of the menu items let you set the side tone. It had been fine, I thought for 600 hours, then my wife started complaining my voice was too loud when I transmitted. We were able to fix it during a long xc just by playing with the setting. WF Link to comment Share on other sites More sharing options...
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