Ads-b hell

[jaylw314]

52 minutes ago, pmccand said:

Umm.  Actually it is correct.  Just got off the phone with uAvionix and because the Skybeacon is not hard-wired into the transponder as are other manufacturers’ devices, it can’t interrogate the transponder frequency unless it receives a ping from ATC.  Therefore, folks using the Skybeacon are routinely sent registered letters from the FAA that they are not in compliance with the Skybeacon even after they have been test flown and approved, when they make flights out of non-radar service airports.  It is definately an issue, and uAvionix is fully aware of thes letters and are in talks with the FAA to rescind their nanny-monitoring of flights that originate outside of radar service areas.  UAvionix was very optimistic that the FAA will change their minds because this requirement was not in the design specifications when the Skybeacon was TSO certified.  The guy at uAvionix was so optimistic that he said we should be getting resolution from the FAA in a couple weeks time.  So, I am holding on to my SkyBeacon for the time being, trusting that they will come to some agreeable resolution.

It does seem like their performance system does know whether you are in rule airspace or not, as I've heard of some people getting their rebates rejected because of inadequate time in rule airspace even though the performance was 100%, so it seems like they have filters they could add to exclude ground performance (since that's not required for the rebate anyway).

I wonder if the Garmin UAT transponder also has this problem (you know, the one they're suing uAvionix for)?  I would assume it does.

[Marauder]

Umm.  Actually it is correct.  Just got off the phone with uAvionix and because the Skybeacon is not hard-wired into the transponder as are other manufacturers’ devices, it can’t interrogate the transponder frequency unless it receives a ping from ATC.  Therefore, folks using the Skybeacon are routinely sent registered letters from the FAA that they are not in compliance with the Skybeacon even after they have been test flown and approved, when they make flights out of non-radar service airports.  It is definately an issue, and uAvionix is fully aware of thes letters and are in talks with the FAA to rescind their nanny-monitoring of flights that originate outside of radar service areas.  UAvionix was very optimistic that the FAA will change their minds because this requirement was not in the design specifications when the Skybeacon was TSO certified.  The guy at uAvionix was so optimistic that he said we should be getting resolution from the FAA in a couple weeks time.  So, I am holding on to my SkyBeacon for the time being, trusting that they will come to some agreeable resolution.

Phil - my comment was directed at the adequate transponder coverage on the ground at the airport. Exactly how does that get done? Transponders are interrogated by secondary radar. Secondary radar doesn’t reach the ground. At airports where they have implemented ground radar for ground traffic control, this may be true, but I am not aware of any uncontrolled field that has ground radar and I doubt most smaller Class C & D have it as well.

The ADS-B coverage map by altitude.

https://www.faa.gov/nextgen/programs/adsb/ICM/

The ADS-B coverage map by services.

https://www.faa.gov/nextgen/programs/adsb/coverageMap/

What I am trying to understand is how in a non-radar coverage area the snitch tape is recording on your ADS-B compliance failure. If you are not in radar coverage, are they saying the ADS-B towers are receiving something from the Skybeacon without the corresponding transponder response? How is that being accomplished when the transponder is not signaling the Skybeacon to trigger. Something doesn’t make sense and I am trying to understand.



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[jaylw314]

22 minutes ago, Marauder said:

Phil - my comment was directed at the adequate transponder coverage on the ground at the airport. Exactly how does that get done? Transponders are interrogated by secondary radar. Secondary radar doesn’t reach the ground. At airports where they have implemented ground radar for ground traffic control, this may be true, but I am not aware of any uncontrolled field that has ground radar and I doubt most smaller Class C & D have it as well.

The ADS-B coverage map by altitude.

https://www.faa.gov/nextgen/programs/adsb/ICM/

The ADS-B coverage map by services.

https://www.faa.gov/nextgen/programs/adsb/coverageMap/

What I am trying to understand is how in a non-radar coverage area the snitch tape is recording on your ADS-B compliance failure. If you are not in radar coverage, are they saying the ADS-B towers are receiving something from the Skybeacon without the corresponding transponder response? How is that being accomplished when the transponder is not signaling the Skybeacon to trigger. Something doesn’t make sense and I am trying to understand.

 

Secondary "radar" is not really radar, right?  I mean, it's just a directional radio signal that you receive on your end with the transponder, it doesn't have to bounce off anything.  In theory, anyway, you should be able to pick up the interrogation signal even if you're on the ground--whether the transmitting radar can RECEIVE your response when you're on the ground is a whole other question, since your transmission is a lot weaker.  But if I understand the Skybeacon method, receiving the interrogation should be enough to set off your mode C transponder.

IIRC when I had a KT-76A, I could see the light flashing even when on the ground at my home airport.

[Immelman]

I wonder if the GDL-82 can self-interrogate the transponder?

Also... I was poking around, and found that on a couple of flights with anonymous mode ON, squawking 1200, I was found and listed on some ads-b tracking websites. How could this be? Well the data from the ads-b tracking folks showed that my skybeacon was transmitting a couple of non-1200 codes.

To me this suggests that perhaps the transponder/skybeacon link is not as robust as it should be...

This is discouraging. I think another test flight is in order with a non-1200 squawk and then I will be giving uavionix a call.