Jump to content
NC Bill

ADS-B Traffic question

Recommended Posts

On recent flights I've noticed traffic not reported on the neither ADS-B IN device yet they are within range and being called out to me by Approach Control who was talking to both aircraft. One was a Citation the others piston. 

 

I thought if a target was on the controller's scope and within my aircraft's range of 1500' and 15 miles I'd see them too. 

 

What am I missing?

Share this post


Link to post
Share on other sites

NC / FL

 

With my IflyGps / SkyGuard ADSB - IN/OUT system,

when I am looking for traffic, I can often see airliners overhead

( when I set for unlimited distance and altitude for alerts), and

I can see other A/C with ADSB equipment, that are nearby.

 

My unit has 4 antennas on it, though, and is portable ( on the

dashboard ).

 

RH

Share this post


Link to post
Share on other sites

On recent flights I've noticed traffic not reported on the neither ADS-B IN device yet they are within range and being called out to me by Approach Control who was talking to both aircraft. One was a Citation the others piston. 

 

 

Without knowing what equipment you have for ADS-B out, it's possible no one is waking up the ground station therefore you won't see any data. That's the downside to something like a GDL-39 or Stratus... picture is incomplete unless you have ADS-B out.

Share this post


Link to post
Share on other sites

My understanding of the system is that even if ground stations are replying, they will only show targets within the activating airplane's "hockey puck".  To see traffic relevant to you you have to both be in range of an activating aircraft, *and* be within its "puck" -- the area that the ground station is transmitting targets for.  The ground station doesn't just fire off every target it knows about, only the ones relevant to activating airplanes; that is to keep displays uncluttered and to save data transmission bandwidth.  So if an airliner hits a ground station, if it's more than 5000ft above you you won't see any traffic except what is close to the airliner.  That would explain why you see the airliner that wakes up the station, but no other traffic around you.

 

I might be wrong on the details, but I am pretty sure that is correct.  

Share this post


Link to post
Share on other sites

I have the DYNON SV-261 transponder + GPS 2020 GPS installed.

 

ADS-B OUT config has been verified by FAA email.

Share this post


Link to post
Share on other sites

My understanding of the system is that even if ground stations are replying, they will only show targets within the activating airplane's "hockey puck".  To see traffic relevant to you you have to both be in range of an activating aircraft, *and* be within its "puck" -- the area that the ground station is transmitting targets for.  The ground station doesn't just fire off every target it knows about, only the ones relevant to activating airplanes; that is to keep displays uncluttered and to save data transmission bandwidth.  So if an airliner hits a ground station, if it's more than 5000ft above you you won't see any traffic except what is close to the airliner.  That would explain why you see the airliner that wakes up the station, but no other traffic around you.

 

I might be wrong on the details, but I am pretty sure that is correct.  

 

What ADS-B equipment are you using?

Share this post


Link to post
Share on other sites

My understanding of the system is that even if ground stations are replying, they will only show targets within the activating airplane's "hockey puck".  To see traffic relevant to you you have to both be in range of an activating aircraft, *and* be within its "puck" -- the area that the ground station is transmitting targets for.  The ground station doesn't just fire off every target it knows about, only the ones relevant to activating airplanes; that is to keep displays uncluttered and to save data transmission bandwidth.  So if an airliner hits a ground station, if it's more than 5000ft above you you won't see any traffic except what is close to the airliner.  That would explain why you see the airliner that wakes up the station, but no other traffic around you.

 

I might be wrong on the details, but I am pretty sure that is correct.  

 

Andy,

 

  I think you're basically correct. I have ADSB IN/OUT with the latest Dynon 14.2.1 software update (will be installing 2020 GPS shortly) and as I fly it wakes up towers nearby and provides known traffic to me. 

  If you don't have ADSB-OUT , or even the latest Dynon update (along with updating the transponder) then chances are you'll also receive traffic alerts on your own airplane. The FAA upgraded ADSB earlier in the year and so Dynon released the series 14 update to allow for their 2020 GPS as well as change the settings of the old GPS to meet the needs of the upgraded ADSB from the ground.

 

  Even with the older Dynon  GPS antenna I get traffic some of which (Mode S) display both their N# and their transponder setting. Some show VFR instead of a dedicated transponder code. I believe the system provides traffic in the envelope around your airplane hence some will disappear as they descend as well as climb.

 

 Passing a large airport today I saw a traffic target pop up climbing quite rapidly directly over me. Its transponder said UPS and it's flight number. Sure enough I looked up and saw UPS climbing about 4000' above after which it left my screen.

Share this post


Link to post
Share on other sites

Not sure what you are asking, Howard. First, the equipment must be certified as fitting the 2020 ADS-B out definition. Second, once it is installed you must fly with it for an hour or so. Then you must request a report from the FAA to verify it is operating correctly.

Share this post


Link to post
Share on other sites

I have the DYNON SV-261 transponder + GPS 2020 GPS installed.

 

ADS-B OUT config has been verified by FAA email.

NC B,

 

Let us know how to get this verification.

 

Is it from LHMFS ?  Maybe we can ask ATC

 

while flying.

 

 

 

RH

Share this post


Link to post
Share on other sites

NC B,

 

Let us know how to get this verification.

 

Is it from LHMFS ?  Maybe we can ask ATC

 

while flying.

 

 

 

RH

Share this post


Link to post
Share on other sites

The URL for ADS=B testing was given above....it's where he tested his gear already.

When I posted mine he had not done it's I am in the process of installing ADS-B on my own with an MRA from Flight Design, so I had the Dynon installation manual handy. I shared the info. Do you object to that?

(I also went on to the site - it looks like it is set up quite well.)

Incidentally, for anyone that may be eligible for the $500 rebate that is the site the FAA provided. Unfortunately, most of our stuff is not in their approved for rebate list.

Share this post


Link to post
Share on other sites

Doug, how's the install going?  What equipment are you using?

 

NC Bill - I see you posted the FAA's website and I repeated what you posted. I should have read the thread better.  Didn't mean to repeat your link.

Share this post


Link to post
Share on other sites

Getting there. I am going slow making certain I understand how things are currently connected. Phone calls to Arian and Dynon. I have the 2020 GPS antenna/receiver installed, the bracket fabricated for the ADS-B in box, my GTX 330 Transponder removed. Still need to create a mounting bracket for the Dynon transponder and connect the in and out to the serial buss on both displays, add power and ground, do the software setup changes, and then have the transponder test done before I can do the test flight for FAA verification. And, of course the paperwork (required equipment, logbooks and I may reweigh since our EAA chapter has scales).

The other piece of this is I will likely replace my 696 with a mini iPad dock and use Dynon's Wi-Fi setup to directly interface with ForeFlight.

All of this as my 95 year old Mom has gone through a fractured vertebrae, a broken hip and now moving from assisted living to skilled care and we are trying to deal with her stuff in a way that makes sense and is respectful of her wishes to the extent that we can.

(Oh, and a bout of sciatica for me.)

Growing old is a PITA.

I am not there yet, but I will have an ES upgradable GTX,330 and probably a 696 for sale soon.

Probably more than you wanted, but thanks for asking. In general life is good!

Share this post


Link to post
Share on other sites

Hey son, I'm 85 yrs young, you are not growing old yet.

Mom is 95. Her cracked vertebrae don't go away and they can't be repaired because it will only lead to others giving way. Her pain is managed but doesn't go away.

My problems are minor, but multiplied by hers. (My brother passed away thirty years ago.)

Oh, and I am getting older... I don't know anyone doing it the other way around.

Share this post


Link to post
Share on other sites

Doug, I've taken care of aged parents and am helping my wife take care of her mother who just turned 90.  It isn't easy but it is pay-back for what our parents did for us.

Share this post


Link to post
Share on other sites

Nice thought, too simple a philosophy, Dick. You don't know my situation any more than I know yours.

It isn't the "taking care" that is the issue, but the not being able to take care of the things like the pain that now keeps her from walking or being independent. The changes in her outlook. You can't change the way I feel about things with tautisms. It is actually a bit insulting that you try.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×