Radio Static when Receiving. Progressively worse through the flight

SixPapaCharlie

SixPapaCharlie

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Here is what it sounds like:

This has been going on for a few months. It is in both radios so likely not a radio itself.
It exists in all 4 headsets.

The radio starts crystal clear and the static gets progressively worse through out the flight until it becomes impossible to understand what the transmitting plane / tower is saying at all.

2 G5s, 2 G430s, GMA 340 audio panel.

Last flight, I did the following tests airborne while the static was at its worst and no change.

Mag check
turned off both alternators
turned off both G5s
turned off the audio panel
turned off and back on both 430s
unplugged all USB devices


Any thoughts on what to check next? I am out of ideas.
 
did you do a sound check? Check one......check one two...........check....check.....one two.....
 
Before every radio call, I do say "testing 1 2 3"
 
Focus on static electricity / static wicks / antennae / antennae mounts.
 
SixPapaCharlie said:
Cirrus does not have static wicks. I am told there is a layer of magic mesh beneath the composite that does something to disperse static but I have no knowledge of what it actually is.
Click to expand...

sounds like it's working!
 
I'd check all grounds, both the radios and around the alternator - but all grounds. Building up during the flight like that sounds like there might be a filtering capacitor somewhere that is going bad.
 
Hang 4 said:
I'd check all grounds, both the radios and around the alternator - but all grounds. Building up during the flight like that sounds like there might be a filtering capacitor somewhere that is going bad.
Click to expand...
I was going to ask if airplanes usually have capacitors on the alternator to stop noise. Caps can work when cold and then not when they get hot. That's what happened to my magneto.
 
SixPapaCharlie said:
The radio starts crystal clear and the static gets progressively worse through out the flight until it becomes impossible to understand what the transmitting plane / tower is saying at all.
Click to expand...
Had a similar problem. The hose that was delivering cooling air was disconnected. As the radios got hot, the sound quality got worse. Check and make sure there is good airflow to keep the avionics cool.
 
SixPapaCharlie said:
Here is what it sounds like:

This has been going on for a few months. It is in both radios so likely not a radio itself.
It exists in all 4 headsets.

The radio starts crystal clear and the static gets progressively worse through out the flight until it becomes impossible to understand what the transmitting plane / tower is saying at all.

2 G5s, 2 G430s, GMA 340 audio panel.

Last flight, I did the following tests airborne while the static was at its worst and no change.

Mag check
turned off both alternators
turned off both G5s
turned off the audio panel
turned off and back on both 430s
unplugged all USB devices


Any thoughts on what to check next? I am out of ideas.
Click to expand...
Start simple. Electrical Contact Cleaner on all the jacks and other easy to reach connections. If that don't work, https://www.trade-a-plane.com/ :D
 
Probably not it but simple to rule out.

Unplug anything that is USB charging and do a simple 30min flight. Especially unplug anything from ships power to usb but I would even unplug power banks too.
 
Now that I've listened, I'd also check shielding on spark plug wires.
 
Bell206 said:
Are you referring to the clicking/rachety noise as the static?
Does the "static" eventually cancel out all radio sound?
Click to expand...

I want to say yes. It gets to the point that I can tell someone is talking but no idea what they are saying.
One more thing I forgot. Yesterday I was flying (That's when I recorded that) I was just about to Squawk 7600 and I unplugged my headset and plugged it back in and instantly everything was crystal clear.
Crap that was an important detail.

Could that be a coincidence? maybe a short in a headset jack but would that impact all the headsets?
Could that have somehow discharged some static build up?

But clearly it is an issue that is capable of correcting itself somehow.
 
SixPapaCharlie said:
I want to say yes. It gets to the point that I can tell someone is talking but no idea what they are saying.
One more thing I forgot. Yesterday I was flying (That's when I recorded that) I was just about to Squawk 7600 and I unplugged my headset and plugged it back in and instantly everything was crystal clear.
Crap that was an important detail.

Could that be a coincidence? maybe a short in a headset jack but would that impact all the headsets?
Could that have somehow discharged some static build up?

But clearly it is an issue that is capable of correcting itself somehow.
Click to expand...
I hate to even ask, but since you left out the headset issue...

You did try another headset.... right?

If memory serves you use a bose?
 
SixPapaCharlie said:
I unplugged my headset and plugged it back in and instantly everything was crystal clear.
Click to expand...
Clear for the rest of the flight or did the static build back?
You say it been that way for a few months, any work done parts replaced at that time when you 1st noticed?
It sounds like a grounding issue.
If you have a handheld radio take it with you and keep both radios on same channel to see if handheld picks it up.
 
SixPapaCharlie said:
I want to say yes. It gets to the point that I can tell someone is talking but no idea what they are saying.
One more thing I forgot. Yesterday I was flying (That's when I recorded that) I was just about to Squawk 7600 and I unplugged my headset and plugged it back in and instantly everything was crystal clear.
Crap that was an important detail.

Could that be a coincidence? maybe a short in a headset jack but would that impact all the headsets?
Could that have somehow discharged some static build up?

But clearly it is an issue that is capable of correcting itself somehow.
Click to expand...
Unplugged jack, plugged jack back in, problem solved. It could be something mechanical as in loose. But the voices in my head still say try contact cleaner. Squirt some on it and like do the ol' in n out with it a few times with some twists.
 
based on this late breaking news yeah, I'd start with your headset connections and go from there.
 
Jim K said:
I hate to even ask, but since you left out the headset issue...

You did try another headset.... right?

If memory serves you use a bose?
Click to expand...

We have 4 sets of Bose in the plane. 2 with LEMO plugs and 2 with the dual jacks. All are getting static.
That audio I shared was from an audio recorder plugged into a pax headset jack so it seems to be headset agnostic.
 
SixPapaCharlie said:
I want to say yes. It gets to the point that I can tell someone is talking but no idea what they are saying.
One more thing I forgot. Yesterday I was flying (That's when I recorded that) I was just about to Squawk 7600 and I unplugged my headset and plugged it back in and instantly everything was crystal clear.
Crap that was an important detail.

Could that be a coincidence? maybe a short in a headset jack but would that impact all the headsets?
Could that have somehow discharged some static build up?

But clearly it is an issue that is capable of correcting itself somehow.
Click to expand...


I've had trouble in the past with my headset ANR creating static. If you're using ANR, try switching it off and see what happens.
 
Bell206 said:
Clear for the rest of the flight or did the static build back?
You say it been that way for a few months, any work done parts replaced at that time when you 1st noticed?
It sounds like a grounding issue.
If you have a handheld radio take it with you and keep both radios on same channel to see if handheld picks it up.
Click to expand...

New PCB but the issue was happening prior.
Unfortunately when it cleared up, I was inbound to land so not a lot of time after to see if it builds back up.
 
Jim K said:
Panama city Beach?
Polychlorinated biphenyls?
Printed circuit board?
Click to expand...

Main board (primary Circuit Board) We had a faulty ALT2 warning. PCB was determined to be the cause. That fixed it.
 
You'd not be having all these problems had you bought a Mooney. Actually, after that video, maybe you would...
 
Does the static go away after Eren falls asleep? Just asking. :)

Please don’t tell her I said that. :)
 
SixPapaCharlie said:
I unplugged my headset and plugged it back in and instantly everything was crystal clear.
Click to expand...

If your headphone and mic plugs are brass, I suggest polishing them with crocus cloth or fine emery paper, them wiping with a rag and contact cleaner. This will remove corrosion.
 
SixPapaCharlie said:
. I am told there is a layer of magic mesh beneath the composite that does something to disperse static but I have no knowledge of what it actually is.
Click to expand...
Lightning protection. It conducts the electrons from wherever the lightning struck the airplane to where it wants out. Composite and wooden airplanes will simply explode if there is no such conductor provided.
 
Maybe your plane doesn't like Bose, try plugging a poor man's headset in and see if it still protests.
 
SixPapaCharlie said:
I was inbound to land so not a lot of time after to see if it builds back up.
Click to expand...
If you don't want to take things apart at this point, fly with a handheld and see if the noise is heard there as well.
Is the noise evident without the engine running and all the electrics powered up?
 
It seems very digital. It’s not quite like GSM noise from your mobile phone but have you tried turning it off and see if it goes away?
 
I suspect the capacitor that sits between the earpieces.
 
Static, I've heard this on Cirrus where someone had broken off one of the wicks. It get bad fast. Sounds like unplugging and replugging your headset is a work around, but better to fix the issue. Could be a grounding issue or something else. Some of this electronic stuff is like magic voodoo to me.
 
Dan Thomas said:
Composite and wooden airplanes will simply explode if there is no such conductor provided.
Click to expand...

cough, cough, explode huh :confused: reminds me of the explosion relief on large ( ok, very large ) ovens. “ It’s for your safety”, yea.
 
Mxfarm said:
cough, cough, explode huh :confused: reminds me of the explosion relief on large ( ok, very large ) ovens. “ It’s for your safety”, yea.
Click to expand...
I studied the Cirrus service and structural repair manual as part of a course on maintaining the airplane. I took Cessna's 400/ttX/Corvalis maintenance course. Both talked about that metal mesh and what it was for.

upload_2022-6-7_8-16-8.png

From https://ntrs.nasa.gov/api/citations/19780003081/downloads/19780003081.pdf

Composites are dealt with later in that paper. Burning-out of resin is one hazard.
 
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