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GTN650 squelch issues

DXB

By DXB
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DXB Grand Master

DXB

Posted
Posted

Grrr...experiencing obnoxious squelch breaks on my newly installed GTN650, along with a new belly com antenna.  Work was done by an experienced Garmin dealer that I'm fairly sure does not suck.  Didn't happen at all for the test flight when picking up. Then it happened  the first couple of flights, but just on the ground.  This weekend it happened continuously for 30 minutes, driving me bonkers and making me switch to the serviceable SL30 I had put in at the same time (which works perfect).  Ideally, the new >10k radio would work better than the 3k nav/com that I just use to listen to ATIS.  I'm trying to look into the factory setup settings myself using the handy internet- the manual is no help. But I hate to give up a bunch of range on the radio to solve this problem.  

I know this has been a fairly common problem, but I would have figured that the bugs would be out by now given the units have been around for a while.  Before I bug the dealer and or Garmin, would folks please share how they ultimately got their GTN650 squelch issues resolved?  Hoping this will be easy, and I won't end up regretting I didn't go with Avidyne.  

Marauder Grand Master

Marauder

Posted
Posted
Grrr...experiencing obnoxious squelch breaks on my newly installed GTN650, along with a new belly com antenna.  Work was done by an experienced Garmin dealer that I'm fairly sure does not suck.  Didn't happen at all for the test flight when picking up. Then it happened  the first couple of flights, but just on the ground.  This weekend it happened continuously for 30 minutes, driving me bonkers and making me switch to the serviceable SL30 I had put in at the same time (which works perfect).  Ideally, the new >10k radio would work better than the 3k nav/com that I just use to listen to ATIS.  I'm trying to look into the factory setup settings myself using the handy internet- the manual is no help. But I hate to give up a bunch of range on the radio to solve this problem.  

I know this has been a fairly common problem, but I would have figured that the bugs would be out by now given the units have been around for a while.  Before I bug the dealer and or Garmin, would folks please share how they ultimately got their GTN650 squelch issues resolved?  Hoping this will be easy, and I won't end up regretting I didn't go with Avidyne.  

Dev - I had an issue with mine. You had a 900 installed as well, correct? Let me see if I can find the thread.

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Marauder Grand Master

Marauder

Posted
Posted

Dev -- make sure the installer had installed the latest firmware updates. There was another one for squelch issues that was issued during the Spring. Sometimes these units are sitting on the shelf for a bit and the firmware is dated.

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Piloto Grand Master

Piloto

Posted
Posted

On my GNS-530AW I can adjust the squelch threshold in the maintenance mode. Check on the GTN 650 Manual. On some COMs the adjustment is done through a pot with a small screw driver. 

José    

DXB Grand Master

DXB

Posted
  • Author
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http://www.mooneyspace.com/index.php?/topic/15572-Tell-me-about----GTN-Squelch-Issues%2E%2E%2E

 

I have an extra ferrite filter you can have if the problem is the JPI.

 

 

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Thanks Chris.  I missed that thread.   I have the JPI900 but no remote annunciator.  Theoretically it could be any similar connection I guess.  I already tried unplugging USB charger in 12V, as this used to happen on mine old setup occasionally- no help.   Will check on the firmware. 

Marauder Grand Master

Marauder

Posted
Posted

The JPI has a pig tail that is wired into the unit. You could still be getting interference from it. Another possibility is that they connected the remote annunciator but didn't mount it on your panel. I would ask what they did. Again, if it is the 900, I have an extra ferrite filter.

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DXB Grand Master

DXB

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Th

What frequencies are impacted?

 

 

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Thought it was just the lowest frequencies at first, as I was getting it only on my home field's ground (121.7) but not tower (126.9).  But then I had it continuously while talking to Atlantic City and Mcguire approach (124.6 and 124.15 respectively).  Interestingly not on the way down to Cape May in afternoon but just in the evening when coming back - the frequencies were much more quiet then and the squelch Rx indicator flickered continuously, driving me out of my gourd.  

DXB Grand Master

DXB

Posted
  • Author
Posted

Out of curiosity, for people who have adjusted their squelch threshold in maintenance mode, where do they set the threshold for best balance of sensitivity and squelch suppression?

Marauder Grand Master

Marauder

Posted
Posted
Out of curiosity, for people who have adjusted their squelch threshold in maintenance mode, where do they set the threshold for best balance of sensitivity and squelch suppression?

Mine is set to 50. Garmin recommends it to be set to 75. As for the problem frequencies, I documented all the ones I had problems with in the thread.

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DXB Grand Master

DXB

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Thanks Chris.  I missed that thread.   I have the JPI900 but no remote annunciator.  Theoretically it could be any similar connection I guess.  I already tried unplugging USB charger in 12V, as this used to happen on mine old setup occasionally- no help.   Will check on the firmware. 

On second thought it might actually be the ipad charger.  I was at the hangar and set up the GTN 650 so that noise was going almost continuously, with all other electrical components turned on. Changing the squelch sensitivity in setup mode made no difference whatsoever (tried 0, 25, 50, 75, and 100).  I worked through all the breakers individually, and only the 12V breaker stopped the noise.  Unplugging the ipad charging cable did the same,while unplugging the Stratus charging cable made no difference. It also made no difference which of the  two12V outlets I used.  

I don't know why this didn't work in flight, but I just ordered 2 ferrite filters to put on the ipad cable, as suggested here: 

http://pointsforpilots.blogspot.com/2013/06/radio-interference-of-12v-ipad-charger.html

I'll also get the com firmware upgraded to 2.2- I think I have 2.13.   

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ArtVandelay Grand Master

ArtVandelay

Posted
Posted

You may have to try a different USB charger, yours could be so bad that even pulling the cables, it still radiates. In my case, my Coms sit right next to the 12v outlet, another cheap option is to get a extension cable so the charger is not so close.

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DXB Grand Master

DXB

Posted
  • Author
Posted

 

 

You may have to try a different USB charger, yours could be so bad that even pulling the cables, it still radiates. In my case, my Coms sit right next to the 12v outlet, another cheap option is to get a extension cable so the charger is not so close.

 

Good idea - ordered a belkin charger - was using a no name one from Sporty's (you'd think an aviation shop would pay attention to quality related such issues but who knows).

aaronk25 Veteran

aaronk25

Posted
Posted

Make sure the power outlet isn't loose. The ground is the panel there isn't any ground wire. Mine was slightly loose and it cauesed me to miss radio calls on a IFR flight using my 650! Had to deal with the FAA on that one. Even a slightly poor ground creates issues.

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DXB Grand Master

DXB

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Make sure the power outlet isn't loose. The ground is the panel there isn't any ground wire. Mine was slightly loose and it cauesed me to miss radio calls on a IFR flight using my 650! Had to deal with the FAA on that one. Even a slightly poor ground creates issues.

 

 

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Yikes  -  A great thought also - my two outlets sit very snugly in a new aluminum panel, but maybe the paint is an insulator and could be removed from inside the cutout?

ArtVandelay Grand Master

ArtVandelay

Posted
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Yikes  -  A great thought also - my two outlets sit very snugly in a new aluminum panel, but maybe the paint is an insulator and could be removed from inside the cutout?

I suspect the backside isn't painted.

thinwing Grand Master

thinwing

Posted
Posted

On second thought it might actually be the ipad charger.  I was at the hangar and set up the GTN 650 so that noise was going almost continuously, with all other electrical components turned on. Changing the squelch sensitivity in setup mode made no difference whatsoever (tried 0, 25, 50, 75, and 100).  I worked through all the breakers individually, and only the 12V breaker stopped the noise.  Unplugging the ipad charging cable did the same,while unplugging the Stratus charging cable made no difference. It also made no difference which of the  two12V outlets I used.  

I don't know why this didn't work in flight, but I just ordered 2 ferrite filters to put on the ipad cable, as suggested here: 

http://pointsforpilots.blogspot.com/2013/06/radio-interference-of-12v-ipad-charger.html

I'll also get the com firmware upgraded to 2.2- I think I have 2.13.   

I had the same problem...the cheapo buttun style belkin ipad chargers are really rf noisy cause they are switch design step down transformer...I have had good luck with the mygoflight cig mount chargers...well shielded,work better than toroid filters...

Mooney_Allegro Proficient

Mooney_Allegro

Posted
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I was notified by Garmin about Comm software update 2.20 on April 1st, 2015 & when I called 2 different Garmin dealers they advised me the Comm software 2.20 is not FAA approved yet.  It's not TSO'd, so legally they couldn't install the update in my Mooney.  Last month I checked with Epps Aviation Avionics shop, they made a phone call to Garmin & it still wasn't approved.  

I've been having the same squelch breaks at the end of incoming transmissions & range issues on the GTN 750 that I can't seem to get rid of.  I routinely monitor the GTN 650 with the same Center frequency when I start losing signal from the 750.  

Anyways, are shops installing the Comm software version 2.20 even though it's not FAA approved?

larryb Mentor

larryb

Posted
Posted

Fluorescent lights in my hanger will break the squelch. Other than that my 650 does not have any of the squelch problems I read about here.

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Marauder Grand Master

Marauder

Posted
Posted
I was notified by Garmin about Comm software update 2.20 on April 1st, 2015 & when I called 2 different Garmin dealers they advised me the Comm software 2.20 is not FAA approved yet.  It's not TSO'd, so legally they couldn't install the update in my Mooney.  Last month I checked with Epps Aviation Avionics shop, they made a phone call to Garmin & it still wasn't approved.  

I've been having the same squelch breaks at the end of incoming transmissions & range issues on the GTN 750 that I can't seem to get rid of.  I routinely monitor the GTN 650 with the same Center frequency when I start losing signal from the 750.  

Anyways, are shops installing the Comm software version 2.20 even though it's not FAA approved?

I have 2.20 installed.

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