Stratus 1 Traffic + ADS-B Questions

[dell30rb]

So i've been flying with the Stratus 1 + traffic on foreflight for a little while now. I'm used to seeing limited traffic, what I assumed are aircraft equipped with ADS-B out.

Yesterday I was flying approaches near my home airport of TTA and I was seeing everything. All of the area traffic. Even our club's old 152 with a single nav/com and only an ancient Mode C Transponder was showing up in the pattern.

Our home airport is equipped with a ground ADS-B station. Its also near RDU whose approach radar would have picked up the 152. Further the Mooney I was flying might have had some sort of ADS-B out Equipment. It has an older king mode C transpoder, garmin 430W and an Apollo MX20 MFD.

If anyone can help me figure out how this works, I would appreciate it.

 

[mikegreen]

I've seen the same in approach areas. My assumption, which based on your observation and confirmation that the 152 doesn't have any wizardly must be right, is that approach radar data goes to ADS-B station and is broadcast as traffic - based on the transponder reply...at that point, Foreflight or any ADS consumer just sees it as traffic without caring if it came from an ADS-B equipped plane or not.

That said, flying in the middle of nowhere I have only seen some Fedex or UPS or SW planes show up in traffic... never seen any GA traffic on foreflight that ATC has called out to me..

 

[JimNtexas]

Here's a good article explaining why you were seeing so much traffic.

But most airplanes (in fact, the vast majority of them today) are not equipped with ADS-B Out, so something has to be done to complete the traffic picture. This is where the ADS-B ground stations come into play. In addition to transmitting weather information (FIS-B), they can also send up traffic data (TIS-B). This traffic data includes all aircraft in radar contact–not just ADS-B Out aircraft.

Between the air-to-air traffic and the ground uplink traffic, you can get a very complete picture of traffic around you. Just like weather, you have to be in range of an ADS-B ground station to receive this data.

There’s a catch

Unfortunately, it’s not that simple–you will only receive this TIS-B information if you are equipped with ADS-B Out. The FAA wants to encourage pilots to equip their airplane with ADS-B Out, so they’re requiring this equipment in order to receive traffic information. Their hope is that this incentive gets more airplanes flying with ADS-B Out, sooner. Many pilots think this is a bad idea, but regardless, it’s the way the system works right now.

All is not lost, though. If you do not have ADS-B Out, but you are flying near another airplane that is transmitting ADS-B Out, you can be a parasite. That is, you can listen in on that airplane’s traffic message and display nearby airplanes on your iPad. That’s because each ADS-B Out airplane receives back an ADS-B In traffic package from the ground stations, and it is specifically tailored to their location. In particular, that ADS-B Out airplane will see all traffic within a 15 mile radius and +/-3500 feet:

ADS-B traffic

So if you’re flying in that “hockey puck” close to a participating airplane, you will have traffic uplinked from the ground, in addition to the air-to-air traffic. This is the best case scenario, as you have free traffic that rivals a $15,000 active traffic system. But as you can imagine, staying within 15 miles and 3500 feet of an ADS-B Out airplane can be a serious limitation. When you’re outside this hockey puck, you will only see air-to-air traffic, which is fairly limited.

(emphasis added)

Somebody near your airport was transmitting an ADS-B 'out' signal. It probably wasn't your Mooney, since that King transponder predates ADS-B.

 

[Pilawt]

Saw this on my iPhone/FF/Stratus I a couple of days ago. Approaching a terminal area where there is air carrier traffic increases the chances of bootstrapping on somebody else's signal.

The "+31" traffic is a jet departing KPDX; the three targets at my one-o'clock are in the pattern at KSPB.

 

[Piloto]

I had the same ADS-B no coverage issue but over the Bahamas and in the Caribbean. For the same cost I opted for the TrafficWatch that works anywhere in the world with my 530 and as a stand alone display. It alerts you by voice and on the 530 when traffic is a threat. This is very handy since you do not need to be looking at a display to asses a threat. Info at http://www.monroyaero.com/ATD300V10.pdf

The picture shows traffic in the pattern from my hangar.

José

 

[Piloto]

Jeff,

I noticed that on your picture the map text is upside down. Is there any way on track mode to make the text up right? Besides the cluttering it is hard for me (over 60) to read text upside down.

José