When I installed the brand new Trig radios and transponder they were clear as a bell .. in any flight conditions …
After 3 plus years I’m starting to get crackles and background noise which is becoming increasingly annoying and distracting.
This has been ongoing for a few months now and what I had passed off as an annoying background buzz has become a pain now …
On Transmit and Receive it’s generally really clear But P1 to P2 is very difficult .. 100% clear on startup and for the first few minutes
The LAA published a really useful multi page guide which I have now started to work through … step by step…
I started by removing and cleaning and refitting the earth points for the main battery to engine earth point … the regulator earth point and both radio headset earth points, Tested today .. 4th Nov and although slightly better for a while .. it came back around 15 mins into the flight.
Reading the article it starts to get you to narrow things down .. like does it go with. Revs, does it go with. Additional power etc
It’s def not tied explicitly to revs … ie like an old unchoked car radio .. the whine increasing with revs .. it DOESNT do that …but … it defiantly gets louder with increased power
NEXT check …. will look at each of the direct battery connections …
my guess .. is that .. in the salty sea air we constantly fly and park in … that, after 3 years plus .. I’m getting build up on various connectors and, as the LAA very useful paper notes, I’m getting arcing where a bad earth is letting build up happen … and then it buzzes as it arcs …
watch this space ….
Jersey Sherwood Ranger 
Hi David
You mention that it doesn’t increase with Revs, but does get louder.
That would lead me to checking all of the positive connections, especially between P1 & P2.
If you imagine that the arcing with an increase in power, is behaving like an old fashioned thyristor volume controller.
If the earth connections can degrade, so too can the positive connections.
I hope this helps
Kind Regards
Nigel
Nigel … very many thanks for taking the trouble to feed back that piece of useful information… I will look at that next … just sitting in bed as I type with the trig diagram out in front of me ! Nice bed time viewing
Really appreciate your helpful feedback and will update the blog when checked… 😉