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Old 06-23-2019, 02:00 PM
FireMedic_2009 FireMedic_2009 is offline
Join Date: Nov 2016
Location: Tampa, FL
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Default PDA360EX Audio Panel

I bought a PDA360EX audio panel replacing my GMA240 which uses the same tray. I have GTN650 as my Com1 and Dynon as Com2. I've noticed that I get squealing intermittenly during transmit especially on Com2. I don't remember getting that on the GMA240.

The PDA360EX has an automatic squelch so there is no adjustment. Is anyone had a similar problem?

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Old 06-23-2019, 04:03 PM
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rvator51 rvator51 is offline
Join Date: Jan 2005
Location: Peoria, AZ
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The Dynon Comm doesn’t have any transmit inhibit circuit/wiring built in so it is possible.

Thomas Velvick
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Old 06-24-2019, 08:47 AM
Canadian_JOY Canadian_JOY is offline
Join Date: Aug 2007
Location: Ontario, Canada
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Squealing is usually a feedback issue where some "leaked" RF energy from the transmitter is being picked up by wiring which ultimately carries it to the audio panel.

I'd go looking for proximity of your COMM1 coax cable to ANY other wiring, particularly if that coax runs in parallel with other wiring. One should strive to keep the coax cables separated from other wiring if at all possible, and if not, the coax should cross other wire bundles at 90 degrees or as close to it as possible in order to minimize the chances of this kind of feedback.

Additionally, if your COM1 coax is the old black RG58 cable you may wish to consider replacing it with the newer gold-coloured RG400 cable which offers better shielding (less energy leaking out).
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