ADS-B Traffic Mystery

[dabney]

I have ADS-B in/out. When I fly around with a friend who has a Garmin 330 ES transponder in his plane he never shows up as "traffic" on my displays.

Figuring it was his plane's transponder we joined up and contacted Joshua Approach Control for radar identification. Joshua identified both of us at the correct altitudes and positions.

I was showing on my display reception from three ground stations, TIS-B traffic operating, and ADS-B traffic operating.

On the way back to the airport after flying together for 30 minutes with ground station reception, his plane popped up on my display with the correct altitude and position for about 3 seconds then disappeared again for good.

I seem to be picking up every other target in my vicinity with proper position, trend and altitude. We flew in many different positions, above, below etc to eliminate antenna masking.

It has me and him stumped. Anybody have any ideas what is causing this?

[rvbuilder2002]

I have no specific ideas, but the first thing I would do is a test to see if it happens with any other airplane with ADS-B in.
Do you know anyone else in the area he could fly near and see if he is blind to them also?

[RV8iator]

Do you have 978 and 1090 in?

I fly with a frind that has an older ADSB in box that is just 978in and he doesn't see me.

[Carl Froehlich]

Recommend you both send an email to the FAA and ask for an ADS-B compliance report. Send a note to this address and include your tail number.
9-AWA-AFS-300-ADSB-AvionicsCheck@faa.gov

The FAA has been very prompt on responding to these requests.

Carl

[DennisRhodes]

What I know about ADSB you can hide behind this period "." but question is: If he had both ADSB In and out. Then the signal from ATC which is being ground based transmitted to him should have both 978 and 1090 traffic for him?? For those of us that just have the UAT I think we should be getting both band traffic from ATC. Above info is not FAA based just my opinion from other people who probably know about as much as me!!

[Larco]

I have a navworx 600b in and out 978 and see 1090 traffic and a friend has a navworx 600 exp in and out 978 and he can see 1090 traffic as well. some we fly with have a dynon 1090 out with 978 in installed and we all see each other.
If this info helps??

It might be your unit, send for ADSB report, that might tell you something.

Larry

[BobTurner]

1. If you have ADSB-out, then buried in the data stream is info on your "in" capability. The ground station will send you traffic info (all traffic they know about, within the 'hockey puck' area around you) on the frequency on which you are listening.
2. Sounds like you and your friend were in formation? Do you have any software filtering to remove self-ghosts? Could it be inadvertantly removing your friend? Or maybe the ground station thinks the two of you are one?

[dabney]

I requested an FAA ADSB report.

In the meantime, my a/c receives on both frequencies. The other plane with a G330 ES receives on 978 and 1090 via a Garmin GDL 39. Oddly enough, he was receiving me with my N Number probably air-to-air since I am ADSB out.

Most of the time we were not so close to each other that we should have been confused as one target. When I said "join up" I meant like formation flying in the Air Force, within the same time zone. Just kidding, a Navy pilot friend of mine told me that one.

We were about a mile apart most of the time. On another flight the same day I was receiving traffic all around me some with their N number. And for the first time I noticed that on some of the aircraft targets displaying their N number it would alternate with showing their squawk code.

What will the FAA compliance report show? Do they need to know where I was and when I was there to check?

[dynonsupport]

I see you're in CA. They recently changed the requirements for ADS-B out to get traffic. What ADS-B OUT system do you have? This may be fully expected.

Is his 330 ES actually hooked to a GPS source?