Noisy radio in a new hdx install


New Member
May 2, 2021
I have a HDX 10 inch , it is a loan unit from the uk dealer as my HDX 10 touch is currently at dynon getting a repair .
New install ( upgrade from D180 and D100 but all new wiring looms.
New SV comm X83
New intercom SV -2s
New knob panel

additionally Funke radio.
Xcruise 100 auto pilot

Coms loom was made to integrate x83 / intercom and the funke radio ( with flip flop switch ) by they

Everything powers up ok and seems to work ok HDX can see every thing and all the Firmware has been updated .
But there is a massive amount of RF ( especially noticeable on 123.450 our test frequency ) that exceeds the squelch of the x83 . The funke radio can squelch it out . The RX symbol can be seen on the x83 .
Via the software setup on the HDX i have adjusted the squelch to max and no change is detected and the rx can still be seen
Working through the fuse panel the only thing that made a difference was when we killed the power to the HDX and then turned it off via the software . At this point both radios where clean and silent.
With everything turned on we have used hand held radios to test the noise floor and check for other RF influences ie, we turned off all the hanger lights as they are LED .

Additionally we have checked the earths are all togther and are a drain and not a earth loop ( and that loom was made by a professional )
I am at a loss as to what to do next. All our tests come back to the HDX giving out a lot of RF noise.

any ideas greatfully received.


Well-Known Member
Oct 10, 2007
Adelaide, Australia
There are several possibilities here -
Did you have this issue before you installed the loaner HDX?
’Test’ outside the hangar (faraday cage if it’s steel) first, before replacing components/avionics.
Coax RG400 or equivalent ?
5volt power supply for iPad etc ? If yes then disconnect it to eliminate that as a cause.
Always do 1 ‘test’ at a time when troubleshooting 😉