GNS 530/430 WAAS loss of GPS Signal

[AZOutlaw]

I see some old threads on this related to antennas but nothing new.  We flew 1.5 hours yesterday and while turning base to land, I got alerts that there was no GPS on either unit.  When we headed home, both units would never find a GPS signal.  I did a lot of restarts and all and nothing worked.  I do have a yoke mounted Garmin 796, and it had GPS the whole time.  This did happen for about 20 minutes back in September but they both came back and worked fine so I assumed a short GPS outage.  A couple of things to note.  While I recently updated the data cards and the Garmin website said they were good, the 430 seemed to have an issue as it said it was referencing true north.  As we were flying along and I was looking for issues I did see one note on the 430....Not receiving input data on 232 channel #3.  The manual just says it's not getting that data, but not what data it is.  Any thoughts?

[IvanP]

It would seem unlikely that both units would fail at the same time. I think that antenna is more likely the culprit here.   

[Jackk]

Seeing AZ in your name, were there any GPS outages in the area?

 

 Military around there loves to mess with the GPS

[skykrawler]

1 hour ago, AZOutlaw said:

 north.  As we were flying along and I was looking for issues I did see one note on the 430....Not receiving input data on 232 channel #3.  The manual just says it's not getting that data, but not what data it is.  Any thoughts?

You can boot the system in maintenance mode and traverse the menus to see what channel #3 has configured for input.   It's good to record all these settings so they can be restored if the unit it repaired or swapped.  And, it also helps you understand how your avionics are interconnected.

 

[GeeBee]

Either antenna or GPS outage.

[AZOutlaw]

1 hour ago, Jackk said:

Seeing AZ in your name, were there any GPS outages in the area?

 

 Military around there loves to mess with the GPS

Could not find any outages and there were none that ATC knew of during the flight.

[Stubby]

I fought an issue similar to this for a while last year with my 530w. Sometimes it would take a long time to acquire signal, sometimes it wouldn't ever acquire signal, and sometimes it would acquire signal just fine then lose it suddenly in the air... really frustrating problem to troubleshoot. I eventually traced it down to either the remote antenna for my stratus or the stratus itself. I replaced both and the problem hasn't showed up again since. About 50% of the time, in flight, with the stratus off and good gps signal on the 530, I would turn the stratus on and my gps signal would immediately disappear.  

[Ragsf15e]

26 minutes ago, Stubby said:

I fought an issue similar to this for a while last year with my 530w. Sometimes it would take a long time to acquire signal, sometimes it wouldn't ever acquire signal, and sometimes it would acquire signal just fine then lose it suddenly in the air... really frustrating problem to troubleshoot. I eventually traced it down to either the remote antenna for my stratus or the stratus itself. I replaced both and the problem hasn't showed up again since. About 50% of the time, in flight, with the stratus off and good gps signal on the 530, I would turn the stratus on and my gps signal would immediately disappear.  

That’s a good point and not always intuitive.  A bad gps antenna can blank other antennas.  If there are separate devices running separate antenna, try turning them on one at a time and see if you can figure out which one kills the other.

[Alan Maurer]

I am based in South Florida and far from Arizona but using G1000 , it often takes a few minutes to acquire a GPS signal. uually by the time I taxi fron hangar to run up area , I manage to get the signal but it can be very slow!! Maybe we can blame The Russians??

Alan

N913ND

[AZOutlaw]

2 hours ago, Ragsf15e said:

That’s a good point and not always intuitive.  A bad gps antenna can blank other antennas.  If there are separate devices running separate antenna, try turning them on one at a time and see if you can figure out which one kills the other.

Thanks guys.  I'm leaning towards an antenna issue.  I updated the data card and went to the airport to see if that cleared.  It did and both radios started up with good GPS.  Second attempt, they did not and I got the same no GPS message.  The next 5 starts resulted in GPS reception but it was really slow and seem to struggle to find the satellites.  The status bars sat blank for awhile until one or two would start to show something    I tried them with the 796 on and off and it didn't seem to matter.  I'll get with an Avionics shop nearby, probably after the holidays, and report back.

Thanks again and Happy New Year (and Happy Flying) to all.

[AZOutlaw]

2 minutes ago, Alan Maurer said:

I am based in South Florida and far from Arizona but using G1000 , it often takes a few minutes to acquire a GPS signal. uually by the time I taxi fron hangar to run up area , I manage to get the signal but it can be very slow!! Maybe we can blame The Russians??

Alan

N913ND

It's very likely a communist plot.  I am close to Sedona though and we get some of that Vortex activity and Harmonic Convergence over here too!!  That's the only way to explain the end of my flight.  My landing was 14100 above the runway at 183 mph  

[MikeOH]

31 minutes ago, AZOutlaw said:

It's very likely a communist plot.  I am close to Sedona though and we get some of that Vortex activity and Harmonic Convergence over here too!!  That's the only way to explain the end of my flight.  My landing was 14100 above the runway at 183 mph  

Nah, more like Area 51

[Hank]

14 hours ago, AZOutlaw said:

My landing was 14100 above the runway at 183 mph  

Now that is talent!!!  

[anthonydesmet]

It’s your WAAS antenna. They do eventually fail with symptoms similar to yours. Had same issue last spring. Easy to replace.

https://www.aircraftspruce.com/catalog/avpages/garminga35waasant.php?clickkey=186169
 

[Pinecone]

I recall reading that the antenna could fail in a way that caused issues with the other GPS if the antennas were close.

Try turning one of them off and then switch which one is on.

So turn Off GPS 2 and see if GPS 1 now works.  Then turn On GPS 2 with GPS 1 Off.

[OR75]

what does the satellites reception menu show ?  are there any bars (hollow) ?

good chances, you may have to redo the 90 degrees TNC connector. get a good quality connector and take your time crimping it to the RG400