Johnnybgoode Posted September 24, 2015 Report Posted September 24, 2015 (edited) Here's a question for the smart guys. Recently I've noticed my radio transmissions on my backup radio are terrible and only just readable on the primary, a GNC300XL. Today I had a chance to play around with it and it seems to be tied to when the generator is making power. Taxiing around and at idle = crystal clear comms. Add power and the generator comes online and my transmissions go downhill fast. So far I've not been turned away from Class C, but I don't like having issues like this any more than the next guy. JPI indicates a solid 14.3V when the generator is online. Any suggestions on where to begin troubleshooting? Come to think of it it's with a new (Halo) headset so I'll start there, but any other ideas are appreciated. Even at half-throttle, with less than full-throttle ambient noise affecting mic, it's nearly unacceptable and it almost sounds like an interference of sorts, not just background noise. Thanks, Patrick Edited September 24, 2015 by Johnnybgoode Quote
carusoam Posted September 24, 2015 Report Posted September 24, 2015 (edited) Good news... i think other people have seen your issue before. Except, they were reporting issues with their alternator.... a couple of questions for you... what voltage controller do you have? Zeftronics are the new solid state ones. The springs, stones and sticks were the old ones... how old is your generator? have you changed the brushes out of it? now wait for the expert you requested already.... best regards, -a- Edited September 24, 2015 by carusoam Quote
Piloto Posted September 24, 2015 Report Posted September 24, 2015 Check the microphone low side connection to the audio panel. If this connection is off or grounded the generator ground return will induce noise into the COM microphone input. Clean the audio panel tray contacts with contact cleaner. José Quote
M204ever Posted September 24, 2015 Report Posted September 24, 2015 Piloto, your explanation fits exactly to the finding we had when a XLR5 has been installed: mic lo was disconnected (corroded) on co-pilot side jack resulting in noisy radio. Quote
Johnnybgoode Posted September 24, 2015 Author Report Posted September 24, 2015 I've got some things to check. I will look at the brushes and see what I can find. Also my '65 has been brought screaming into the 80's with the Zeftronics upgrade, though not recently. It might very well be related to the mic connections. I'll have a look at those as well. Thanks guys! Quote
Yetti Posted September 24, 2015 Report Posted September 24, 2015 I don't know about the C, but the F I has has a big ole Capacitor on the starboard firewall that I believe is there for noise reduction. Capacitors have been known to go bad. Quote
MyNameIsNobody Posted September 24, 2015 Report Posted September 24, 2015 I have a 300GNC as my Com 1. IT is WAY weaker in reception than Com 2 King 155. Always has been that way. I had all kinds of charging issues until replaced/upgraded to Zefttronics/replaced generator. Replaced Antennas. Hope you get it sorted soon. Voltage amps/volts in digital vs. old sixpack analog was a no-brainer too. Quote
Marauder Posted September 24, 2015 Report Posted September 24, 2015 On 9/24/2015 at 2:16 AM, Piloto said: Check the microphone low side connection to the audio panel. If this connection is off or grounded the generator ground return will induce noise into the COM microphone input. Clean the audio panel tray contacts with contact cleaner. José To add to José comments, also check the jacks for the headsets. I had a noise issue caused by one of the jacks touching the frame and grounding it. Quote
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