Originally Posted by Witkin
I am flying an RV-12 with a Dynon HDX. I am not the builder so my understanding of the systems is not great. There is a Dynon 2020 GPS antenna.
I get a warning that the ADSB HAS FAILED AND LOSS OF GPS.
Has anyone else had this happen and where do I begin to correct it?
Actual message “POSITION SOURCE 1 FAIL
NO ADS-B OUT. GPS LOST
You have a position source. Your SkyView has a position as you have synthetic vision displayed. If you have a total GPS position failure, you would not have it.
First, do you have another GPS feeding it like a Garmin, Avidyne, or a GPS-250 puck? You need to determine what is your POS 1 source is and what is giving you the position for the synthetic vision. These are all in settings if you know where to look. Your synthetic vision source might be a POS 2 source or a GPS 1 source. Also what is your setting for the position source in the transponder settings.
Input Function Considerations and Priorities
SkyView's Moving Map Page uses POS and GPS sources for its data. Regardless of the number of data sources in your system, this page prioritizes these sources and fails over to them as follows:
POS 1, GPS 1, GPS 2, GPS 3, GPS 4, POS 2, POS 3, POS 4
For example, if your system has one SV-GPS-2020 configured as POS 1 and a Garmin 396 configured as GPS 1, the Moving Map will always use the SV-GPS-2020 as its primary data source. If the SV-GPS-2020 fails or you configure its input function to NONE, the Moving Map Page will use the Garmin 396 (or other GPS source) configured as GPS 1 as its primary data source.
If you have a GPS-250 puck as POS 2, then your system might be using it as the position source for the map and synthetic vision.
I find that the Dynon GPS is a lot more sensitive than say my Garmin 175 in my hanger, but do pull you aircraft outside and see if you get a position on POS 1.
The first thing I would check it if the GPS-2020 is up and running by going in to the setup menu, press and hold down buttons 7 and 8 at the same time until you are into the setup menu. Then go to System setup, then Serial Port setup, then serial port 5. Is the GPS-2020 detected and set as POS 1, and sending data out by the TX counter number going up? If it is, the press the back button, button 1, until you are in the main setup window. The go down to Local Display Setup, then GPS Fix Status. On the top right is will tell you what you are using for the present position source, the one giving you the map and synthetic vision position.
I don’t mean to ramble on, but these are things that should be checked out. The setup has things you can see that might help troubleshoot a problem, and sometimes it is just is setting that might just need to be changed.
If you want to do a little more troubleshooting, you can email me at firstname.lastname@example.org
and I will do what I can to lead you down the right path.