COM static

The ramblings of our community of aviators.

Moderators: Rick, Lance Murray

User avatar
photoSteveZ
4 Diamonds Member
4 Diamonds Member
Posts: 321
Joined: Wed Dec 23, 2020 4:10 pm
First Name: Steve
Aircraft Type: DA62
Aircraft Registration: N62DZ
Airports: KEIK Erie CO
Has thanked: 387 times
Been thanked: 226 times

Re: COM static

Post by photoSteveZ »

Boatguy wrote: Mon Apr 11, 2022 1:47 pm The MAN SQ on the audio panel is for the intercom. My problem is with COM1/2.
Have a look at this at around the 5:00 minute mark. It's a trifle ambiguous, but I think it says you can adjust the COM manual squelch using the audio panel's volume knob.

https://www.youtube.com/watch?v=shq06MJDbpk
User avatar
Boatguy
5 Diamonds Member
5 Diamonds Member
Posts: 1828
Joined: Mon Jan 22, 2018 4:48 am
First Name: Russ
Aircraft Type: DA62
Aircraft Registration: N962M
Airports: KSTS
Has thanked: 1329 times
Been thanked: 1163 times

Re: COM static

Post by Boatguy »

That what is says, though I'm pretty skeptical as the manual says that adjustment is for the intercom. The audio panel doesn't seem to have much interaction with the GIAs, where the COM radios live, though obviously something is arbitrating the audio from the COM, Intercom, Phone, Music and CAS. COM interrupts Music and Phone for example.

I'm going to try to go by the plane today or tomorrow and experiment in the hangar.
User avatar
Boatguy
5 Diamonds Member
5 Diamonds Member
Posts: 1828
Joined: Mon Jan 22, 2018 4:48 am
First Name: Russ
Aircraft Type: DA62
Aircraft Registration: N962M
Airports: KSTS
Has thanked: 1329 times
Been thanked: 1163 times

Re: COM static

Post by Boatguy »

The Phase II installation work instructions make reference to setting the COM sidetone levels. Anyone understand that enough to know if it is related to this problem?
Screen Shot 2022-04-11 at 8.22.47 AM.png
User avatar
Steve
5 Diamonds Member
5 Diamonds Member
Posts: 1953
Joined: Thu Aug 12, 2010 1:23 am
First Name: Steve
Aircraft Type: DA40
Aircraft Registration: N432SC
Airports: 1T7
Has thanked: 81 times
Been thanked: 493 times

Re: COM static

Post by Steve »

Russ:

Not at all familiar with G1000, but generally, sidetone refers to the sound level of the transmitted signal in the transmitter's own headset.
User avatar
Boatguy
5 Diamonds Member
5 Diamonds Member
Posts: 1828
Joined: Mon Jan 22, 2018 4:48 am
First Name: Russ
Aircraft Type: DA62
Aircraft Registration: N962M
Airports: KSTS
Has thanked: 1329 times
Been thanked: 1163 times

Re: COM static

Post by Boatguy »

photoSteveZ wrote: Sun Apr 10, 2022 11:37 pm I don’t have an airplane with G1000 avionics right to hand, but I recently learned you can adjust the Com squelch when it’s set to manual squelch, using the pilot’s volume knob on the audio panel. Similarly, you can adjust the intercom’s manual squelch (when the audio panel’s manual squelch is lit), for both the pilot and copilot/passengers. Can’t wait to try this, because I never figured it out when I had my ‘interim’ DA62.
I went to the plane today and did some testing, as well as queried Garmin who were unusually responsive and informative.

The short answer from Garmin, which confirmed what I saw in the plane:
On the COM1/COM2 for the G1000NXi, there is only the on/off for the auto squelch, no in between.
  • I defeated the COM squelch with the Vol knob and then twisted to see if it made any adjustment. It did not and continued to change the volume.

    The MAN SQ on the audio panel had no effect on COM, as expected.

    The NXi Pilot's Guide description of the behavior of the GMA1360 is horrendously ambiguous and inconsistent, even for Garmin.
I'm curious now if there is a configuration setting for the MASQ "master avionics squelch" which is referred to in the manual, but it's very unlikely that was changed at my annual so it would just be out of curiosity and isn't likely to be the source of my problem.

Today, in the hangar, the static mostly went away after a few minutes. Past behavior has made me wonder if it was just "warming up", or it went away due to altitude. To be continued...
User avatar
Karl
4 Diamonds Member
4 Diamonds Member
Posts: 318
Joined: Wed Aug 04, 2010 3:58 am
First Name: Karl
Aircraft Type: DA40
Airports:
Has thanked: 68 times
Been thanked: 102 times

Re: COM static

Post by Karl »

As you speculate that this started after the last annual I would be looking at what work was done and what was disconnected/removed during the maintenance. The DA40 has extensive bonding straps throughout the airframe and any high resistance in the bonding system due to corrosion or a bad connection can induce noise on the comms. The bonding strap on the tailplane hidden behind the elevator is very prone to corrosion. Also, any corrosion on the static wicks mounting can also create noise on the comms.
User avatar
DragonFly
2 Diamonds Member
2 Diamonds Member
Posts: 12
Joined: Sun Nov 24, 2013 2:01 pm
First Name: Jonathan
Aircraft Type: DA42
Aircraft Registration: N892MA
Airports: KWDR
Has thanked: 3 times
Been thanked: 7 times

Re: COM static

Post by DragonFly »

Had this happen on one of my 40s a while back, was an older one, that had low time. It had started later, maybe one hour or so, into flights. Then it started happening earlier and earlier. When we finally had our 1000 hr bonding inspection, we found over half of the static wicks were bad. Once replaced, no more issues. May be something to check.
User avatar
Rich
5 Diamonds Member
5 Diamonds Member
Posts: 4592
Joined: Mon Aug 30, 2010 12:40 pm
First Name: Rich
Aircraft Type: DA40
Aircraft Registration: N40XE
Airports: S39 Prineville OR
Has thanked: 145 times
Been thanked: 1180 times

Re: COM static

Post by Rich »

I've experienced this intermittently. Not bad enough to be a problem, but hard to diagnose (being intermittent and all). Weird. I monitor SEA Center when locally and one transmission from center will be fine and the next static-filled. Which COM/antenna doesn't seem to matter, but for a given aircraft they're talking to it'll be consistent :scratch: . For other folks on CTAF, it'll come and go. Then there are weird pops from nowhere on either frequency.

Anyway, today I'm flying around in the area doing T&Gs and whatnot and all transmissions in both radios come in crystal clear the whole flight. I'll take it :thumbsup: .
2002 DA40-180: MT, PowerFlow, 530W/430W, KAP140, ext. baggage, 1090 ES out, 2646 MTOW, 40gal., Surefly, Flightstream 210, Orion 600 LED, XeVision, Aspen E5
User avatar
mhoran
4 Diamonds Member
4 Diamonds Member
Posts: 476
Joined: Fri May 23, 2014 11:56 pm
First Name: Matt
Aircraft Type: DA40
Aircraft Registration: N269RB
Airports: KLDJ
Has thanked: 121 times
Been thanked: 244 times

Re: COM static

Post by mhoran »

Rich wrote: Mon Apr 18, 2022 11:50 pm Which COM/antenna doesn't seem to matter, but for a given aircraft they're talking to it'll be consistent :scratch: .
I've experienced this as well, most recently just this past weekend. I suspect this may have to do with RCAG sites which extend the range of ATC frequencies. They may or may not be activated at a given time based on who the controller is talking to. It also seems they are not always active even when they should be, which can lead to particularly challenging communication at times.
User avatar
Boatguy
5 Diamonds Member
5 Diamonds Member
Posts: 1828
Joined: Mon Jan 22, 2018 4:48 am
First Name: Russ
Aircraft Type: DA62
Aircraft Registration: N962M
Airports: KSTS
Has thanked: 1329 times
Been thanked: 1163 times

Re: COM static

Post by Boatguy »

In my case the static is when nobody is talking, actual transmissions come through clearly 98% of the time. It's like the squelch was open at times, though it is not.

The static wicks are a possibility I've discussed with my IA so I'm probably going to get that checked.
Post Reply