rhtrudder Posted June 13, 2016 Share Posted June 13, 2016 plane has just developed a radio buzz on receive , the buzz goes up and down with the engine revs, volts look ok, replaced reg not that long ago, I have little knowledge when it comes to these problems, hoping someone can give me some ideas. engine is a 914 ,1350 hrs Link to comment Share on other sites More sharing options...
spacesailor Posted June 14, 2016 Share Posted June 14, 2016 Iv'e heard that sound before!, can't recall wether a bad earth or a bad alternator diode, and don't forget alternators do have brushes. also check the RF capacitor. spacesailor Link to comment Share on other sites More sharing options...
rhtrudder Posted June 14, 2016 Author Share Posted June 14, 2016 Driving me nuts, hard to track down the problem , the uhf unit doesnt pick it up so it maybe in the vhf aerial somewhere Link to comment Share on other sites More sharing options...
spacesailor Posted June 17, 2016 Share Posted June 17, 2016 Hi, You will let us know what the problem was, when sorted please. spacesailor Link to comment Share on other sites More sharing options...
rhtrudder Posted June 17, 2016 Author Share Posted June 17, 2016 Might have to get radio nurd mate to figure it out Link to comment Share on other sites More sharing options...
sain Posted June 18, 2016 Share Posted June 18, 2016 Check the earth shield on the coax hasn't come loose at either the connector at the back of the radio or at the antenna mount. You can use a multimeter to check that out Check the power connections to the radio - in particular make sure the ground connector is clean and making good contact. Try adding a power filter to the line coming to the radio, which may help a bit. 1 Link to comment Share on other sites More sharing options...
sain Posted June 18, 2016 Share Posted June 18, 2016 sorry, i should have said why to check that stuff. Most often those sounds of noise issues come about due to a grounding problem. Coax connectors are generally pretty reliable, however they can fail, particularly in high vibration environments. I said the power filter may help, but if its a ground issue then basically you have one (or more) part of the electrical system using a ground with a different voltage on it to the rest of the system. The power filter doesn't really address that problem, but if the underlying issue is dodgy power filtering in your radio, it might alleviate the issue a bit. anyway, good luck. 1 Link to comment Share on other sites More sharing options...
rhtrudder Posted June 18, 2016 Author Share Posted June 18, 2016 Thanks for that , I will get on it as soon as my strip dries out a bit Link to comment Share on other sites More sharing options...
spacesailor Posted July 14, 2016 Share Posted July 14, 2016 Is it still buzzing!. spacesailor Link to comment Share on other sites More sharing options...
rhtrudder Posted July 14, 2016 Author Share Posted July 14, 2016 Is it still buzzing!.spacesailor Won't stop raining, thanks for the interest Link to comment Share on other sites More sharing options...
rhtrudder Posted July 14, 2016 Author Share Posted July 14, 2016 Is it still buzzing!.spacesailor Won't stop raining, thanks for the interest Link to comment Share on other sites More sharing options...
Darracq Posted July 30, 2016 Share Posted July 30, 2016 Not sure if it will help but I just brought a tranceiver and it came with a ferrite core to wrap the 12v cigarette lighter charger cable around. Meant to stop interference. Link to comment Share on other sites More sharing options...
rhtrudder Posted July 30, 2016 Author Share Posted July 30, 2016 Worth a try Link to comment Share on other sites More sharing options...
Jabiru7252 Posted July 31, 2016 Share Posted July 31, 2016 Have you wound the radio squelch so far back it picks up all noise? That's a common mistake. You adjust squelch with the motor running so only your voice gets through. Start with the simple sh*t first. Is a hand-held radio close by picking up the noise? Disconnect the antenna - if the noise goes then the interference is coming via the power cable. Hard to help when I'm not there... Link to comment Share on other sites More sharing options...
Geoff_H Posted August 3, 2016 Share Posted August 3, 2016 All low voltage audio cables need to be shielded. The shield MUST be rather at ONE end only. If not you can get earth loops, they will be at a multi of the engine frequency, usually double. Link to comment Share on other sites More sharing options...
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