iFly GPS Forum

While flying this morning with SkyRadar feeding my '720, I received a traffic red alert indicating a target at my exact altitude and 0.1 mile. This ghost (obviously myself) tracked within 0.1 to 0 miles, with the reported altitude within 20 - 30 feet of my barometric indicated. I did have one other target on the screen, which must have turned on my cell.

I then put my transponder into standby, and the altitude and location accuracy suffered, but the red triangle was still following. I then turned mode C back on, and the accuracy of my altitude and location zeroed right back in, and stayed with me until I dropped below radar coverage.

I'm pretty sure that I've read of this behavior on the '700 and '720 before. Before upgrading to the '720 recently, I used Wing X on my iPad for SkyRadar functions for over a year, and I don't ever recall seeing a "ghost" there.

Is this something that can be addressed in the iFly software?

David

Paul,

This is a known issue with the ADS-B traffic on a receiver only device. Without sending your position via ADS-B out, your Mode C or S Transponder is sending your location to ATC and then the TIS-B broadcast is sending that "Your Target" back out to your ADS-B receiver as a traffic target. The receiver does not know it is you, only that it is a traffic target from the TIS-B.

This is one of the big reasons the ADS-B Transceiver is the most accurate, along with having limited traffic in uncontrolled areas. It knows where you are and to not report "own ship" is as traffic. It might be an option to omit very close traffic, but that would not the be safest answer as this close traffic scenario in the most critical. It's just a know issue with ADS-B receivers only in regards to Traffic. They were really designed for the Weather side of ADS-B. I hope this helps.