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  #1  
Old 08-16-2018, 12:27 PM
Michael Wellenzohn's Avatar
Michael Wellenzohn Michael Wellenzohn is offline
 
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Location: Zuerich, Switzerland
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Default Strange GPS loss

I just returned with the family from a two weeks flying vacation in Southern Europe. On my last leg from Cannes in France my GNS 430W lost GPS Signal after about 30 min of flight. Also my trutrak ADI didnít show the GPS indicated course although equipped with its own GPS mouse therefore independent from the GNS.
My iPad however still had full GPS signal strength from a Bluetooth gps mouse.
I do every flight in this configuration since years and this has happened three times in the last two years but never before. Not critical since Iím flying VFR only but I still wonder what a potential reason might be. For all three events no similarities could be identified in terms of location, manipulation of devices etc.
Has anyone in the wide RV universe a clue whatís going on?

Kind regards
Michael
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  #2  
Old 08-16-2018, 12:59 PM
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Brantel Brantel is offline
 
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If your GA35 antenna is failing, it can start to resonate and could possibly swamp nearby GPS's causing them to lose signal lock. Some devices are more prone to this than others. There have been many reports of this over the past several years. Many years ago when I had a 430W I personally experienced this and the GA35 was the source of the issue.
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  #3  
Old 08-16-2018, 01:20 PM
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istrumit istrumit is offline
 
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Default

Unlikely, but, the only time this happened to me was going into Albuquerque NM around the same time the Defense Department conducted an un-announced GPS jamming experiment.

Two airliners on Center complained, and then a few minutes later I lost mine as well.

By that time I had dialed in the OBS.

Regardless, no issue...just the DoD doing is thing.
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  #4  
Old 08-16-2018, 01:33 PM
noelf noelf is offline
 
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The OP did not specify which GPS antenna(s) were being used. But from other post about this antenna:

* Garmin outsourced this antenna from another manufacturer.

* The early GA35 antennas were very, very susceptible to over tightening of the 4 mounting screws. When over tightened, the antenna base and circuit board were stressed and the circuit board cracked, leading to intermittent operation.

* The antenna was redesigned, but still had some issues with over torque of the mounting hardware. This lead to the warning tag on the antenna units that limited the mounting bolts install torque. (Sorry, I do not recall the value, but it is something like 10 or 15 in/lbs).
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  #5  
Old 08-16-2018, 02:45 PM
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Thermos Thermos is offline
 
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FAA-certified GNSS boxes like the GNS-430 use only WAAS GPS, but it's possible that your iPad GPS mouse is using GLONASS and/or Galileo in addition to GPS. If that's the case, it's quite possible that your iPad would still have a good position fix even if there's interference to GPS only.

It's certainly not impossible that there's something wrong with one of your GPS antennas, but my money is on external interference or jamming.

Dave
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Last edited by Thermos : 08-16-2018 at 03:11 PM.
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  #6  
Old 08-17-2018, 04:41 AM
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RV10inOz RV10inOz is offline
 
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Quote:
Originally Posted by Brantel View Post
If your GA35 antenna is failing, it can start to resonate and could possibly swamp nearby GPS's causing them to lose signal lock. Some devices are more prone to this than others. There have been many reports of this over the past several years. Many years ago when I had a 430W I personally experienced this and the GA35 was the source of the issue.

WHAT BRIAN SAID x 1,000
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  #7  
Old 08-17-2018, 06:52 AM
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rleffler rleffler is offline
 
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Quote:
Originally Posted by Brantel View Post
If your GA35 antenna is failing, it can start to resonate and could possibly swamp nearby GPS's causing them to lose signal lock. Some devices are more prone to this than others. There have been many reports of this over the past several years. Many years ago when I had a 430W I personally experienced this and the GA35 was the source of the issue.
I've experienced this as well. Do you have a GA35?
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  #8  
Old 08-17-2018, 03:23 PM
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Michael Wellenzohn Michael Wellenzohn is offline
 
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Thanks for all the replies. I do have an GA35, is there a known method to test it before I invest 300$ in a new antenna? As mentioned it didnít occur often.
Regards
Michael
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  #9  
Old 08-17-2018, 03:35 PM
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Brantel Brantel is offline
 
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Quote:
Originally Posted by Michael Wellenzohn View Post
Thanks for all the replies. I do have an GA35, is there a known method to test it before I invest 300$ in a new antenna? As mentioned it didnít occur often.
Regards
Michael
Next time it happens where the GNS drops out and other GPS's drop out at the same time, turn off the power to the GNS and see if the others immediately restore signal.

If they do, it is likely the GA35....
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---------------------------------------------------------------------
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Lyc. O-360 carbed, HARTZELL BA CS Prop, Dual P-MAGs, Dual Garmin G3X Touch
Track N159SB (KK4LIF)
Like EAA Chapter 1494 on Facebook
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  #10  
Old 08-17-2018, 04:12 PM
Jrskygod Jrskygod is offline
 
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Brian if I recall didn't you find an alternative antenna for the GA 35 that solved the problem?
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