Static on Comm 1

[warren.huisman]

I have recently had a530W installed in my panel in place of a GX60.  Also installed a Garmin 345 transponder to be ADSB compliant.  A couple months after the install, I started to get intermittent static where the Comm breaks squelch.  Initially, it wasn't too bad and I basically ignored it.  However, it became so bad, that the Comm was basically useless as it drove me nuts with all the static.  It seems to send and receive effectively, but the static otherwise drove me nuts.

Long story, short - the avionics shop who installed the radio has not yet been able to determine root cause.  Even consulting with Garmin has been unfruitful.  Any ideas?

 

[Piloto]

It is not unusual to need to readjust the squelch setting on a new installation.

José
 
Page 5-16 500W Series Installation Manual Rev. G 190-00357-02  
5.3.10 COM SETUP Page (GNS 530W Only) 
Select the COM SETUP page (see Figure 5-13).  These values are set at the factory and seldom require calibration.  Older versions of software will not show all choices. 
FREQ 
Selects a VHF communication frequency.  For purposes of setting the squelch and sidetone levels, only the frequencies 118.000, 127.000, and 136.975 MHz can be used. 
SPACING 
Selection Description 25.0 kHz Selects traditional 25 kilohertz spacing (760 channel). 8.33 kHz Selects 8.33 kilohertz channel spacing, which is required in some areas of the world

[Marauder]

I have recently had a530W installed in my panel in place of a GX60.  Also installed a Garmin 345 transponder to be ADSB compliant.  A couple months after the install, I started to get intermittent static where the Comm breaks squelch.  Initially, it wasn't too bad and I basically ignored it.  However, it became so bad, that the Comm was basically useless as it drove me nuts with all the static.  It seems to send and receive effectively, but the static otherwise drove me nuts.
Long story, short - the avionics shop who installed the radio has not yet been able to determine root cause.  Even consulting with Garmin has been unfruitful.  Any ideas?
 

What else do you have in the panel? The GX-60 may have been immune to an already present RF source in the plane. José’s squelch adjustment should address it, but if it doesn’t, you may need to shield the offending gizmo.


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[warren.huisman]

Sl15 audio panel, sl30 nav/com, flight stream 210, strike finder, Aspen 1000 pro pfd, vm1000 engine monitor.

 

The issue is, I get the static on the ground with all this stuff off.

 

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[Marauder]

Sl15 audio panel, sl30 nav/com, flight stream 210, strike finder, Aspen 1000 pro pfd, vm1000 engine monitor. 

The issue is, I get the static on the ground with all this stuff off.

 

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I fought a couple of static issues that were opening the squelch. The first one was caused by the JPI 900. Required a ferrite filter on the remote engine warning light.

 

The second one was caused by the location of the pilot headset jacks relative to the Aspen PFD’s power lead. Ended up shielding the jacks.

 

When you said it was doing it with everything off, were the breakers for everything other than the radio and audio panel pulled? If you haven’t already tried the co-pilot jacks, I would make sure it isn’t isolated to the pilot jacks.

 

Since it happened over time, it could be just an adjustment of the squelch circuitry. What is troubling is that this is something Garmin would have suggested as a fix.

 

 https://youtu.be/C_I-OjGJI-U

 

 

 

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[Marauder]

There are other things that can open a squelch on a com radio. I would look through any changes you made like using a cigar lighter, new headset and any other carry on stuff.

My high priced GTN 650’s squelch opens when I turn on my hangar’s LED lights.


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[Bob_Belville]

I hear static on COMM (GTN 750) sometimes in front of the hangar. It goes away when I taxi clear of the buildings.

[Piloto]

Check the GNS 530 antenna cable shield connection to ground at both ends. An improperly attached shield to the connectors will invite panel noise.

José

[carusoam]

See if @TrekLawleris visiting... Garmin squelch issue

-a-

[Baker Avionics]

Is it worse or how is it when the engine is running?  Also, what type of turn coordinator do you have?  If you have a "brush type" Turn Coordinator, when checking out your Comm radio, pull the CB for the Turn Coordinator because that is a common cause.  Further, if you do NOT have the static when engines are NOT running, but the static is bad when it IS running, open the cowl and look at the shielding of your magneto "P Leads".  If they are not shielded correctly, that will wreak havoc on the Comm radio.  While in the engine compartment, be sure there are no old wires that have not been removed from the engine compartment leading into the cockpit because it will take all of that RF generated in the engine area and induce it into the cockpit causing static as well.  I just fixed this very same issue on a "J Model" the other day with a 530W and a 345 setup, which is really a moot point.  The owner has had this issue for years and could not figure it out at various shops he went to.  Once we fixed it, which we did, it was almost "too quiet".  Good luck and if I can help, let me know.  

[Baker Avionics]

As far as the GTN 750/650 breaking squelch, there are adjustments your Avionics Shop can make in the configuration settings to adjust the squelch settings to a more suitable level.  It is actually outlined in the Installation Manual.  These new radios come from Garmin adjusted SO sensitive that adjustments ARE required at the installation facility to combat this very issue.  If you need help/getting the excerpt from the manual, let me know.  I am glad to help out.

[warren.huisman]

Well, the issue is not yet resolved.  It appears that the noise goes away when the aspen is shut down.  They found some improperly grounded and shielded wires but so far has not yielded any better results .  It still does it with the engine off.

[Marauder]

Well, the issue is not yet resolved.  It appears that the noise goes away when the aspen is shut down.  They found some improperly grounded and shielded wires but so far has not yielded any better results .  It still does it with the engine off.

Sorry, haven’t followed everything you have tried. When you test it with the engine off, are you isolating the GTN by only powering up the radio and audio panel? I would pull all the breakers except for the audio panel and radio to see what that does. Then bring things back on line by the breaker.

If the Aspen is the cause, I would call them and see what they have to say.


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[warren.huisman]

If i understand correctly, they are only able to make the static go away by powering off the Aspen.  I believe the other avionics except 530 and audio panel are also powered down.  They swapped the Aspen with one from the mechanics plane with the same results.  So, i doubt it is the Aspen but something associated with it (wiring, etc)

 

[Baker Avionics]

16 minutes ago, warren.huisman said:

If i understand correctly, they are only able to make the static go away by powering off the Aspen.  I believe the other avionics except 530 and audio panel are also powered down.  They swapped the Aspen with one from the mechanics plane with the same results.  So, i doubt it is the Aspen but something associated with it (wiring, etc)

 

This may sound SOOOO STUPID, but try unplugging the Aspen and then put the CB fo the Aspen in to see if there is an accessory hooked to the Aspen causing it.  Also. ensure that the shields between the 530W and the Aspen, assuming they are connected, are NOT grounded on both ends.  It could be causing what is known as a "Ground Loop" which will cause this very thing.  If there is a difference of potential between the 2 ends where they are grounded, it will cause static as power wants to seek ground from one place to another.  Just try and ensure that they are not grounded on BOTH ends.  It will cause one to chase ghosts and go bald!  Hope it helps!

 

Edited October 18, 2018 by The Avionics Specialists
Misspelled a word

[Marauder]

3 hours ago, The Avionics Specialists said:

This may sound SOOOO STUPID, but try unplugging the Aspen and then put the CB fo the Aspen in to see if there is an accessory hooked to the Aspen causing it.  Also. ensure that the shields between the 530W and the Aspen, assuming they are connected, are NOT grounded on both ends.  It could be causing what is known as a "Ground Loop" which will cause this very thing.  If there is a difference of potential between the 2 ends where they are grounded, it will cause static as power wants to seek ground from one place to another.  Just try and ensure that they are not grounded on BOTH ends.  It will cause one to chase ghosts and go bald!  Hope it helps!

 

This is a good suggestion as I believe the rear mounted RSM may be getting power from the same breaker. I think the ACU or EA-100 have their own breaker (at least I know I have a separate breaker for my ACU).

[Baker Avionics]

12 hours ago, Marauder said:

This is a good suggestion as I believe the rear mounted RSM may be getting power from the same breaker. I think the ACU or EA-100 have their own breaker (at least I know I have a separate breaker for my ACU).

Let me know what you find by doing this.  Or if the Avionics Shop does it.  I wish there was a way to get it here or for me to get there to troubleshoot.  Hope it helps.  Good luck my friend!!!

[Yetti]

Did we pull all the USB converters out of the cigarette lighter plugs?

[Marauder]

This may sound SOOOO STUPID, but try unplugging the Aspen and then put the CB fo the Aspen in to see if there is an accessory hooked to the Aspen causing it.  Also. ensure that the shields between the 530W and the Aspen, assuming they are connected, are NOT grounded on both ends.  It could be causing what is known as a "Ground Loop" which will cause this very thing.  If there is a difference of potential between the 2 ends where they are grounded, it will cause static as power wants to seek ground from one place to another.  Just try and ensure that they are not grounded on BOTH ends.  It will cause one to chase ghosts and go bald!  Hope it helps!
 

I wasn’t familiar with the the concept of “ground loop” until I looked up a YouTube video on the topic. I suspect if people are moving or installing their headset jacks, not properly isolating their headset jacks could be the source of many radio interference.

This is what happened to me. When Bruce Jaeger and I installed his Spatial Designs interior, it forced me to move my pilot side headset jacks to the instrument panel (much easier location to access than the factory spot on the sidewall). The headset jacks for sidewall installation were mounted into a piece that was attached to the plastic sidewall. When the jacks were moved to the instrument panel area, the correct insulators were not installed and a small whine was introduced when the avionics were powered up.

I knew this was isolated to the pilot jacks but not why. Well, once the correct insulators were installed, no more whine. So paying attention to the details does pay off. Thanks!

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[warren.huisman]

Thanks for the information.  He does a nice job explaining the ground loop phenomena.  I'll keep you posted if this solves the issue.  fingers crossed.

[INA201]

I had all kinds of static too.  We found multiple issues.

1.  Unshielded wire connecting alternator was replaced.

2. JPI900 was wired in too close proximity to audio panel and GTN750 which was causing some feedback among other things.

3.  Comm wires were separated as best possible.

4.  Had a break in the shielding for the ignition wires so replaced that.

5.  Cleaned battery connections.

 

All in all a lot of trial and error but with diligence it is all clear as a bell now.  This is probably not your issue but may be some insight for others.

[warren.huisman]

Well, the static issue is still ongoing .  I have changed the ignition harness because it was recommended by the repair shop and i was getting some "stumbling" with the right Mag with a Mag check in flight.  The rough engine on the right Mag is still there with the new harness.  I don't have the issue on the ground at 2000 RPM - only in the air.  Any ideas?  Mag issue?  Spark plug(s)? I have fine wire plugs but not sure of the age.

 

[carusoam]

Stumbling and mag issues go hand in hand...

What mags do you have?

How many hours since they were last serviced/OH’d?

A lot more than 500 hours?

Another thing could be as simple as checking what spark plugs you have in there?

If Champion, look up how to measure their resistance... standard procedure for Champion has become clean, gap, measure resistance, get disappointed, replace with the other brand...   

Got an engine monitor?  Can you identify which cylinder is acting up? You should be able to identify what plug isn’t working...

PP thoughts only, not a mechanic...

Best regards,

-a-

[warren.huisman]

Stumbling and mag issues go hand in hand...

What mags do you have?

How many hours since they were last serviced/OH’d?

A lot more than 500 hours?

Another thing could be as simple as checking what spark plugs you have in there?

If Champion, look up how to measure their resistance... standard procedure for Champion has become clean, gap, measure resistance, get disappointed, replace with the other brand...   

Got an engine monitor?  Can you identify which cylinder is acting up? You should be able to identify what plug isn’t working...

PP thoughts only, not a mechanic...

Best regards,

-a-

Not seeing any significant differences on the engine monitor. It has the single drive, dual mag on this one. I think I’ll try swapping the plugs left mag and right mag and see if it follows them or stays with the mag. Not many other components I don’t think. Less than 200 hours on the mag since overhaul.

 

 

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[carusoam]

Downloading the data is a great way to find the stumbles...

Make sure your monitor is set up on the fastest period between collecting data points... a stumble is very momentary, if your monitor is set to 6 seconds, it may be really hard to see...

Savvy has some good advice on doing this if you are not familiar...

Check your logs for the word Champion and see how many hours are on the plugs...

Was the stumble during ROP or LOP? 

Have you run a GAMI spread? This will help indicate if a Fuel injector is giving you the hassle...

Savvy also has the procedure for this too...

PP thoughts only, not a mechanic.

Best regards,

-a-