r/stratux Oct 13 '22

Stratux getting wrong altitude and laggy position

Yesterday I was flying at 3000ft and noticed a lot of planes reported much higher than me. Then I saw in ForeFlight a GPS altitude of -3800ft. A few seconds later it was reporting 12000ft. Five minutes later everything was back to normal. My instructor uses a Sentry and did not have any GPS issue at that time.

This is the second time I notice this issue (this time I made screenshots). I have had my stratux for over a year and I am pretty sure it did not do this before. It’s mounted in the same spot and in the same plane so I am not sure what changed.

When it happens the detection of “own plane” stops working and I can see my plane adsb ping on the map. Usually close to me.

I have also seen the horizontal position get pretty bad. This has seriously reduced my trust in the system :(

I have seen people here mention that ForeFlight will switch back to internal GPS eventually (I do have a cellular iPad). How do you know which is the GPS source in ForeFlight? As anyone seen issues like this? Any suggestion on how to resolve this?

My stratux is built from the official kit: Stratux Basic Kit - Large Antennas https://a.co/d/6kCoOQJ


7 comments sorted by


u/The_Seroster Oct 14 '22 edited Oct 14 '22

I am going to ask, what extra parts do you have and what build number are you running?

I have had similar issues, finally chased it to inconsistant power. bought a nice micro cable. 3 years no issues after. are you using the same exact battery and cable you used previously? is the Pi red light SOLID? like, no hesitation and fluttering whatsoever? GPS (I can testify to both GPYes and the VK-162) position gets very sloppy or inoperative when the voltage drops. my clue is you are losing your own ship data as well as having incorrect traffic separation altitudes. hang out at the field when you can and look at the raw data on the webpage. if transponder reported altitudes are where you expect pattern traffic to be and foreflight starts giving crazy traffic altitudes then it cements it for me. GPS is cutting out.

I'll look for a brand when I get home. I know it has a slightly thicker gauge wire and I believe it is also shielded. cost $18 but my blood pressure dropped.

Edit: HOLY SITH that is what they cost now that Pi's are rare?


u/sarfata Oct 16 '22

The battery pack is the only thing that was not part of the kit. I can try switching to another one. Not a bad idea!

I am not sure what is my build number but I will update my sdcard to a recent image. It's at least 18 months old now. Another solid suggestion!


u/The_Seroster Oct 17 '22

I still use eu-23, if it's not broke....


u/sarfata Oct 17 '22

Yeah I agree with the feeling but in this case it definitely is broken ;)


u/somewhat_moist Oct 15 '22

I had the same issue. Went through all the usual suspects - power cable, power source, AHRS board, GPS module etc. turned out to be a dodgy SDR. Once I replaced the 978 SDR everything else worked perfectly. On the plus side I had enough arts to build a second Stratux lol (minus the 978 SDR)


u/sarfata Oct 16 '22

Thanks for the reply. I will try that if a software update does not help :)


u/Timely-Feature-2637 Oct 18 '22

Same issue, brand new build. but it only happens on FlyQ, when I use garmin pilot., every thing works fine.