Tell me about -- GTN Squelch Issues...

[Marauder]

I think you know all about my 750 issues, the 650 solid as a rock since new.

I can get my new 750 to break squelch on some frequenceys in the 122 range if I am using one perticular cigerate lighter USB power adapter.

If I remove the USB cable from the adapter (which I have multiple permanant... well plugged in always for my (IPad, Clarity SV, Phone) the squelch clears up. Again only with one of the cheap 12 vdc to usb power adaptrers the 2 better quality units I have seem to not have any problems.

Hope any of this helps in any way!

Keep us posted, but if your other radio is having issues would seem to me there might be something else that could be causing radio frequency interferance. Just a wild guess on my part.

Thanks Lacee. I have been trying to run it clean. I don't use any USB devices plugged into the lighter adapter nor is anything else "non-certified" in the panel. I unloaded a lot of stuff last night on the flight back up to Philly. It didn't seem to make a difference. The only thing I am holding out for is the service note from Garmin that specified a 75 setting on the squelch. I know the shop set it to 50. I may not be correct, but I thought squelch had a direct impact on distance that the transmitter could transmit. Anyone know the specifics?

[RocketAviator]

You can easily adjust the squelch settings yourself as I recall. Get into setup mode when powering up and adjust.

I've done it a few times but not recent enough to recall precise instructions.

I did not notice any difference in my distance capabilities and I made a number of changes to the squelch threshold

[Marauder]

You can easily adjust the squelch settings yourself as I recall. Get into setup mode when powering up and adjust.

I've done it a few times but not recent enough to recall precise instructions.

I did not notice any difference in my distance capabilities and I made a number of changes to the squelch threshold

 

You're correct. I learned about the "hold Menu" while powering up access. I'm just SO pissed about the whole thing! It replaced a MX-170B that although had some issues, I never worried about it in the system. Hear that Peter Garmin?! I can't!

[RocketAviator]

You're correct. I learned about the "hold Menu" while powering up access. I'm just SO pissed about the whole thing! It replaced a MX-170B that although had some issues, I never worried about it in the system. Hear that Peter Garmin?! I can't!

Understand your frustration completely, I too was so unhappy after spending all that $$$ for what I was told was the best..

Well you know all to well the story.

keep me posted you and I can't be the only two who have had these issues...

[Marauder]

Understand your frustration completely, I too was so unhappy after spending all that $$$ for what I was told was the best..

Well you know all to well the story.

keep me posted you and I can't be the only two who have had these issues...

 

 Thanks Lacee. I know there are others who are struggling with this. Garmin has been sending out a steady stream of COM updates specifically to address the open squelch issue. The shop i am working with has seen this, but it seems that each plane has their own situation to contend with. Not what I expected with a TSO installation...

[RocketAviator]

Todays 2hr flight no issues

Hope you get your resolved ASAP...

Keep me posted

[PTK]

You're correct. I learned about the "hold Menu" while powering up access. I'm just SO pissed about the whole thing! It replaced a MX-170B that although had some issues, I never worried about it in the system. Hear that Peter Garmin?! I can't!

It's the Aspen that's at fault.

[flyboy0681]

I'm wondering if I'm having a squelch problem myself where weak transmissions are not coming through. Last month while I was flying up to Hickory, North Carolina for some weekend R&R, I was in contact with Columbia Approach proceeding toward Spartanburg VOR and noticed chatter on the frequency was getting less and less. After trying to raise Columbia for a couple of minutes I called Atlanta Center informing them that I was on Columbia's frequency and that I couldn't raise them. Atlanta responded that I was in radar contact and the flight proceeded uneventfully.

 

Three weeks later I got a certified letter from the FSDO opening an inquiry into the situation. If there was a question about the loss of communications, I sure wish it would have been conveyed to me at the time via the dreadful "call this phone number once you land". At least the entire episode would have been fresh in my mind.

[Marauder]

I'm going to make a video including the audio of the radio. Last summer I was having issues with range and the shop installed one of the Garmin Com firmware updates. I can't say it fixed it but I also didn't have the squelch issue.

Over the past 2 years I would hear the squelch break few times but it was just a momentary thing and hard to discern from radio chatter. About 3 weeks ago, it became pretty prominent. On certain frequencies the squelch was open and although I could hear ATC mixed in with the open squelch it was hard (that was the root of the BUTTS versus BUNTZ issue I was joking about on another thread) to hear what they were saying. On some frequencies, it was crystal clear and the squelch functioned normally.

The symptom is fairly obvious. The squelch is open and although transmissions are there, they are intermingled with the background noise. If my 22 year old Narco was behaving, I wouldn't be upset about this. But both radios are in a conspiracy against me. If this keeps up, the fat ladies will sing as they sit on both of them.

One troubling thing is the Garmin recommendation to run the squelch up to 75 (%?). I suspect this will keep the squelch closed, but it is my understanding that transmit power and squelch setting go hand in hand. Can anyone confirm this? The shop that is working on this has it set for 50 but the Garmin service note says to set it to 75. I will be trying to get it back to the shop this week.

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[Marauder]

I'm wondering if I'm having a squelch problem myself where weak transmissions are not coming through. Last month while I was flying up to Hickory, North Carolina for some weekend R&R, I was in contact with Columbia Approach proceeding toward Spartanburg VOR and noticed chatter on the frequency was getting less and less. After trying to raise Columbia for a couple of minutes I called Atlanta Center informing them that I was on Columbia's frequency and that I couldn't raise them. Atlanta responded that I was in radar contact and the flight proceeded uneventfully.

Three weeks later I got a certified letter from the FSDO opening an inquiry into the situation. If there was a question about the loss of communications, I sure wish it would have been conveyed to me at the time via the dreadful "call this phone number once you land". At least the entire episode would have been fresh in my mind.

Loss Coms can be a big deal especially if they don't realize you are not following their direction. When this squelch issue popped up for me, I was in the soup for a good portion of the trip and I wasn't prepared mentally for a dual loss Com situation. I remedied this today by making a copy of 91.185. I guess I should have been mentally prepared for it, but who really practices loss Coms?

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[Marauder]

Here are the frequencies that worked and didn't.

Problem frequencies: 124.1, 123.7, 125.15, 124.35 (all had open squelch sounds that ATC needed to transmit through) and 126.25 (local AWOS)

Working frequencies: 134.8, 133.35, 127.47, 123.05

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[flyboy0681]

Loss Coms can be a big deal especially if they don't realize you are not following their direction. When this squelch issue popped up for me, I was in the soup for a good portion of the trip and I wasn't prepared mentally for a dual loss Com situation. I remedied this today by making a copy of 91.185. I guess I should have been mentally prepared for it, but who really practices loss Coms?

 

 

I did adhere to 91.185 by proceeding along the route that was last assigned to me.

[drapo]

Marauder, one of my fellow Mooney pilot here in Lachute had a similar problem after the installation of his new GTN650.

He tried everything including changing antenna location, cables, connectors and finally invested an additional $7000 to replace his KX155 with a Garmin GNC225A.

It's now working fine... That's part of why I decided to give a chance to the underdog and went with Avidyne...

[Marauder]

Marauder, one of my fellow Mooney pilot here in Lachute had a similar problem after the installation of his new GTN650.

He tried everything including changing antenna location, cables, connectors and finally invested an additional $7000 to replace his KX155 with a Garmin GNC225A.

It's now working fine... That's part of why I decided to give a chance to the underdog and went with Avidyne...

Any chance he can share what finally fixed it?

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[drapo]

Any chance he can share what finally fixed it?

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Maybe a combination of factor, could be the KX155 itself that was interfering with the GTN650 or a compatibility issue with non-Garmin equipment, all he knows is that the $7000 cured his problems...

[Marauder]

Update: I was able to determine what is causing the squelch to open on the GTN. Now I am on the quest to figure out how to correct it.

In late May, I upgraded my JPI 830 to a 900. I'm pissed because I didn't link the change to the problem. It is very reproducible, pull the JPI breaker and it goes away.

Any ideas what on the JPI could be causing this? I would have hoped that both the JPI and GTN would have filtering circuits to prevent this.

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[carusoam]

Wow, very interesting...

What could cause electrical noise out of a JPI...?

Check for various ground wires to see if they are connected?

Check the engine's grounds as well. A sensor wire can be leading back to the JPI...

Sharing ideas, I have no experience in this area.

Good luck,

-a-

[Marauder]

Wow, very interesting...

What could cause electrical noise out of a JPI...?

Check for various ground wires to see if they are connected?

Check the engine's grounds as well. A sensor wire can be leading back to the JPI...

Sharing ideas, I have no experience in this area.

Good luck,

-a-

Definitely a strange one. Both of my JPIs were/are center mounted above the audio panel. Since there were no issues with the 830, I have to suspect the extra sensors or the unit itself.

[N601RX]

One of the sensor wires may be picking up noise from an ignition wire. Is the problem still present with the engine off? Also the Jpi does not get its ground from the airframe, it has to be grounded directly to the engine. Perhaps the noise could also be getting in on the rs232 wires that run between the Jpi and Garmin boxes. If it's comming in on electrical lines, there are filters available.

[Marauder]

One of the sensor wires may be picking up noise from an ignition wire. Is the problem still present with the engine off? Also the Jpi does not get its ground from the airframe, it has to be grounded directly to the engine. Perhaps the noise could also be getting in on the rs232 wires that run between the Jpi and Garmin boxes. If it's comming in on electrical lines, there are filters available.

I spoke to JPI today (Tim). Said he never heard of the issue, but wanted to run it by the R&D engineers. He then called me a few minutes later and asked if I could disconnect the remote warning light to make sure that wasn't the issue.

As for the engine off, good question. I will try that tomorrow (I'm off all week -- so this is what retirement feels like?!). The avionics shop also called Garmin and they replied with "never heard about that problem before".

The ground is an interesting topic. I will call the shop that installed it and see where they grounded it. I went through the installation manual and noted that comment as well.

I also mentioned the fluctuating MP issue to Tim at JPI. Didn't get a "never heard that before" comment, but didn't offer up a solution but did ask for my data from June. My MP data looks just like yours, about an inch of fluctuation.

Will keep you posted. Thanks for the engine off suggestion.

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[Marauder]

I spoke to JPI today (Tim). Said he never heard of the issue, but wanted to run it by the R&D engineers. He then called me a few minutes later and asked if I could disconnect the remote warning light to make sure that wasn't the issue.

As for the engine off, good question. I will try that tomorrow (I'm off all week -- so this is what retirement feels like?!). The avionics shop also called Garmin and they replied with "never heard about that problem before".

The ground is an interesting topic. I will call the shop that installed it and see where they grounded it. I went through the installation manual and noted that comment as well.

I also mentioned the fluctuating MP issue to Tim at JPI. Didn't get a "never heard that before" comment, but didn't offer up a solution but did ask for my data from June. My MP data looks just like yours, about an inch of fluctuation.

Will keep you posted. Thanks for the engine off suggestion.

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Update: this video says it all, just change my word "sensor" to "indicator" in the video. No resolution thus far.

http://youtu.be/C_I-OjGJI-U

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[carusoam]

Wow. Nice problem identification.

What's the next step?

Best regards,

-a-

[Marauder]

Wow. Nice problem identification.

What's the next step?

Best regards,

-a-

Unit is going back to JPI for the manifold pressure issue and waiting for them to figure out what to do with the squelch opening issue.

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[PTK]

Very happy for you that you finally identified your issue. Happy resolution!!

And you thought it was Garmin!

Chris, Chris, Chris!!

[jlunseth]

Wow.  Thanks. Marauder.  I'll bet that is it. I have what sounds like an open mike issue on some frequencies.  Constant background static.  I wonder if that is what it is??

 

I also have a whiz bang expensive 430AW that I bought new, the "A" part being for the stronger 16 watt transmitter, and it does not help, it is not uncommon for me to lose ATC especially if I am up high and their are thunderstorms in the vicinity.  I have had it checked out several times and it went back to Garmin once, found to be out of spec on the bench, was brought back into spec and that helped for awhile but was not permanent.  I was actually at Garmin for a pilot seminar and there was another fellow there with the same transmitter and the same issue as mine, we tried to talk to the Garmin people but they were not helpful.  I have an old King radio that is more dependable than the Garmin when it comes to reception, and when I lose ATC I switch to that radio first, before trying other frequencies, etc.  You really do have to listen to the chatter and if you are not hearing ATC you need to do something about it.