iFly GPS Forum

Here is an update on chasing the erratic NMEA stream from the 720. I purchased a new USB/serial adapter cable from Adventure Pilot to replace the one I've used for several years (different brand, not sure of the source). I also confirmed the iFly, Trio, and Straux share common grounds and am pretty sure the Dynon is also grounded at the master ground block. The new cable transmits a huge amount of noise into the audio of the plane on several frequencies which was never present with the old cable. The NMEA dropouts still occurred and could only be resolved by rebooting the iFly application. The new cable was unusable so I switched back to the old one which does not generate any noise but still has NMEA failures.

I'm at a loss to explain the NMEA problems, and looks like I may have to take the iFly out of the loop and feed the Dynon and Trio with just a dumb Garmin GPS35. This means no flight path tracking on the Trio but it will still fly a heading. Sure wish this problem could be resolved but I don't know what else to try. I've used the ancient GPS35 puck with the Trio and Dynon previously and it is rock solid.

I once mounted my Stratux under the dash to both hide it from view and keep it out of the sun.  After a few flights with seemingly unrelated radio issues (ATC could hear me but the freq was silent when they spoke), I accidently discovered that the Stratux was throwing off enough EMI to cause the problem.  Further investigation by other Stratux users with scopes determined that the Stratux EMI was pretty much centered on comm freqs.  I had previously discovered that the iFly 740 power cord was causing comm interference, and I resolved that issue by placing a small ferrite choke on the iFly power cord.  I suggest 1) turning off the Stratux and 2) placing a ferrite choke on the power cord of the 740 to rule out those two sources.