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-   -   ADS-B "Save" (https://vansairforce.net/community/showthread.php?t=153326)

rv7boy 09-14-2017 01:56 PM

Quote:

Originally Posted by BoilermakerRV (Post 1204024)
I believe that ATC ground stations will send up radar target data to ADS-B IN equipped aircraft. Although there may be an interrogation required. Others are better versed in this technology than I.

I understood that, too, but I haven't found it yet except in blogs and social media. I've been reading material on ADS-B from FAA, AOPA, Garmin, Appareo, Sporty's and others, and I haven't found yet that radar data is or will be sent to ADS-B in equipped aircraft.

Would someone provide the link? If it's so, it needs to be publicized better, IMO.

jliltd 09-14-2017 02:00 PM

Quote:

Originally Posted by GalinHdz
I don't think the twin had ADS-B OUT since it never displayed a tail number, BUT it could have been in "anonymous" mode. If it didn't have ADS-B OUT but was being "painted" by ATC, it should have shown up anyways. BTW, "see and avoid" will always be the ultimate collision avoidance system while flying.

Very astute observation on your bogey, Galin. ADS-B Anonymous Mode is just that, anonymous. Anonymous doesn't mean "invisible". When a UAT out aircraft elects to use anonymous mode while squawking VFR (only time anonymous works) that aircraft is still completely visible and shown in the system for both ATC and other aircraft. The only difference is that the ICAO code (and N Number) are randomized for privacy reasons. So an ADS-B "in" display will then show "VFR" instead of the N Number and all other critical information is still shown (altitude, speed erc...). Since all you saw was an unidentified target w/o tail number or "VFR" this means that the Seneca probably didn't have ADS-B out but his Mode C was being relayed to your ADS-B "in" reciever by the ground stations.

snopercod 09-14-2017 02:04 PM

Quote:

Originally Posted by BoilermakerRV (Post 1204024)
I believe that ATC ground stations will send up radar target data to ADS-B IN equipped aircraft.

That's the way it's supposed to work. I fly with ADS-B IN and not all traffic shows up.

slngsht 09-14-2017 02:27 PM

Quote:

Originally Posted by snopercod (Post 1204027)
That's the way it's supposed to work. I fly with ADS-B IN and not all traffic shows up.

I've had short flights where I have 3 towers, and no traffic shows up on foreflight. I know it's not my display settings, because on the next flight, I see plenty of traffic on the map.

Bicyclops 09-14-2017 02:37 PM

How it's supposed to work
 
ADS-B in should bring you weather info and traffic info, called TIS-B or traffic information service. Anybody nearby transmitting ADS-B out info on the UAT frequency will show up directly. Any targets the ATC is seeing on their radar or ADS-B stations are picking up should be re-broadcast to you. But, and this is the rub, if you are not broadcasting ADS-B out, you will not trigger the re-broadcast. You have to count on somebody in the same vicinity as you with out capability to trigger the re-broadcast.

Anonymous mode only works with UAT ABS-B out. If you have a Mode S xpdr, you are never, ever anonymous.

Ed Holyoke


Quote:

Originally Posted by snopercod (Post 1204027)
That's the way it's supposed to work. I fly with ADS-B IN and not all traffic shows up.


Aluminum 09-14-2017 02:45 PM

Quote:

Originally Posted by rv7boy (Post 1204022)
What do you mean by "painted?" I take that to mean "on radar." But I don't think there is a link between ATC's radar and the ADS-B system. If so, tell me how, because I haven't found that yet in my study of ADS-B.

I believe the way it works is that Dynon's transponder receives TIS-B "in" which contains up to five nearest radar targets as seen by ground radar and/or their ADS-B "out" caught by ground stations. I don't have ADS-B "in" on my Skyview but still receive nearby traffic targets when near metropolitan areas. Update frequency is several seconds, longer than between ADS-B packets I see on 1090 MHz, and direction of motion indicated tends to waver for targets in straight&level, which would indicate radar pings as the source, perhaps.

BobTurner 09-14-2017 03:03 PM

Here's how it is suppose to work:
1. If you have adsb-out, and -in, and are in contact with an adsb ground station, and
2. There is a nearby aircraft that is known to the system-either it has adsb-out and is talking to an adsb ground station, or it is within atc radar coverage, and if it has ASB-out it is on a different frequency than your adsb-in, then
3. The adsb ground station is suppose to send you that aircraft as traffic.
Radar coverage is not the same as ADSB ground station coverage.

BTW, if you are in VMC collision avoidance with vfr traffic is the pilot's - not ATC's - responsibility. You must keep looking, even if on an ifr flight plan.

Timberwolf 09-14-2017 03:06 PM

I have 2 planes at Milton...you really have to keep your head on a swivel. You have Navy/Marine Helos and T6's, Air Force T6's and T1's, Hurlburt and Eglin Traffic, plus all the commercial and flight training just within a 20 NM radius. ADSB is always welcome in this area though you won't necc get the whole picture without ADSB out, or someone nearby with ADSB out. They do train heavily at eglin so I'm sure it was as you described, a trainee and a supervisor. However, there are a **** load of aircraft in the local area without transponders as well who don't talk and won't show up on radar or ADSB. It's very surprising that being IFR they were behind giving you advisories. Stay safe out there

maus92 09-14-2017 03:53 PM

Quote:

Originally Posted by slngsht (Post 1204033)
I've had short flights where I have 3 towers, and no traffic shows up on foreflight. I know it's not my display settings, because on the next flight, I see plenty of traffic on the map.

Are you equipped with ADS-B Out? If not, you may not receive traffic because you have not been letting the ground stations know you are nearby. On the next flight, a participating ADS-B Out aircraft may have been nearby and triggered the ground stations to transmit data.

GalinHdz 09-14-2017 04:10 PM

Quote:

Originally Posted by rv7boy (Post 1204025)
I understood that, too, but I haven't found it yet except in blogs and social media. I've been reading material on ADS-B from FAA, AOPA, Garmin, Appareo, Sporty's and others, and I haven't found yet that radar data is or will be sent to ADS-B in equipped aircraft.

Would someone provide the link? If it's so, it needs to be publicized better, IMO.

OK, to be more specific:

If ATC is "painting" his non ADS-B transponer response, then you should see him on your ADS-B display. Don't confuse Primary (raw) radar with Secondary (transponder) radar. The caviat is that you must be within ADS-B ground station coverage to see non ADS-B transponer responses.
Quote:

Originally Posted by Timberwolf (Post 1204038)
I have 2 planes at Milton...you really have to keep your head on a swivel. You have Navy/Marine Helos and T6's, Air Force T6's and T1's, Hurlburt and Eglin Traffic, plus all the commercial and flight training just within a 20 NM radius. ADSB is always welcome in this area though you won't necc get the whole picture without ADSB out, or someone nearby with ADSB out. They do train heavily at eglin so I'm sure it was as you described, a trainee and a supervisor. However, there are a **** load of aircraft in the local area without transponders as well who don't talk and won't show up on radar or ADSB. It's very surprising that being IFR they were behind giving you advisories. Stay safe out there

Oh yes. Plus an added benefit of having your head on a swivel in this area is you might get to see some super cool aircraft you otherwise would not see.

:cool:


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