At the AOPA Carbondale Fly In, I spoke with a representative from uAvionix about ADS-B. My question was that I have heard of some sort of satellite connectivity in the ADS-B system. I noted my experience with extremely limited ADS-B In coverage, while using a Stratus portable device. He launched into a very assertive discussion essentially claiming that, had my airplane been equipped with ADS-B Out, I would have had excellent ADS-B In coverage, via satellite connectivity. He kept saying that “You need ADS-B Out to complete the loop with the satellites.” He repeated that argument several times. I asked him as many times what satellite system this purportedly used, but all he’d say was....”It’s all part of the system.”.

I wandered down the aisle and there stood two gents from the FAAs Next Gen Program......which owns and operates the ADS-B program.

I first asked them if there is a satellite based component to the ADS-B system. They both responded with a yes. I asked the function of that system. They responded that this system is the GPS satellite array. I asked if that system has any other role in ADS-B than providing location data to your WAAS enabled GPS, which feeds data to ADS-B Out? Nope, both agreed.

I then asked if there is ANY other satellite system that connects with the ADS-B system? Firm “Nope” from both.

I then repeated what the gent at the uAvionix booth had told me, and asked for their thoughts. They both said that what he was describing was simply wrong....there is no satellite system involved with ADS-B other than the GPS position data. And the ADS-B unit does not talk to that system.

Be careful what you believe with vendors trying to sell stuff.

MTV

Aerion is launching satellites for a space-based ADS-B system for global coverage without the cost of ground stations...so there is/will be an entire ADS-B system based on satellites.

https://aireon.com/

I have been told similar things and I think it came down to a lack of understanding. I believe ADSB-in traffic data WAS dependent on where the ADSB-out hits were coming from, triggering the “puck” of airspace around the ADSB-out equipped airplanes for traffic data, but I have heard that the system was changed to just spew out all traffic data all the time so you should see who’s around you no matter if you have ADSB-out or not. The only other reason now that makes a difference for in if you have out is enabling ownship ADSB so it removes your own airplanes target from the traffic display. Without ADSB out I don’t think you can remove your own target which is just a minor annoyance.

Yes, but not all the US systems (and maybe none of them) will talk to that system. For one thing, the US antennas are on the bottom. I asked the FAA guys if it’s possible to install two antennas (top and bottom) on an airplane. Their response was that it’s been tried and doesn’t work with existing equipment.

MTV

mtv wrote:Yes, but not all the US systems (and maybe none of them) will talk to that system. For one thing, the US antennas are on the bottom. I asked the FAA guys if it’s possible to install two antennas (top and bottom) on an airplane. Their response was that it’s been tried and doesn’t work with existing equipment.

MTV

FWIW, nav Canada has done lots of testing and the satellites pick up the bottom antenna just fine. The sats only run on the 1090 frequency though.

Reminds me of the old joke:

What is the difference between a technology salesman and a used car salesman? The used car salesman knows he is lying.


I’d expect more from the smaller world of aviation but have run across countless people selling or representing stuff they know very little about and it is not immediately obvious until you start probing around a bit.

Tech salesmen are the worst.

They either know that they know nothing and won’t provide any helpful answers, or they think they know (but don’t, otherwise they would be an engineer) and give you the wrong answer.

I’m not terribly impressed with uavionix, but I’ll probably end up with their echo box because it will talk gdl90 to my experimental EFIS, talk to my phone/iPad, being 978mhz, it will go into anonymous mode when I squawk VFR, and because it does in and out, it can filter me out of the radar info, which removes my shadow when in anonymous mode.

I wish someone else would make a solid in/out box that wasn’t so expensive or proprietary.

A1Skinner wrote:

mtv wrote:Yes, but not all the US systems (and maybe none of them) will talk to that system. For one thing, the US antennas are on the bottom. I asked the FAA guys if it’s possible to install two antennas (top and bottom) on an airplane. Their response was that it’s been tried and doesn’t work with existing equipment.

MTV

FWIW, nav Canada has done lots of testing and the satellites pick up the bottom antenna just fine. The sats only run on the 1090 frequency though.

Good to know on the bottom antennas. But, yes, that's what the FAA guys told me, was that everyone else in the world is going to 1090, so since most of the "small airplane" ADS-B units are 978, they wont' work on those systems. And, indeed the uAvionix units are 978......

Fortunately, so far, there's no place I NEED or want to go that will require ADS-B.

But, the uAvionix guys didn't impress me with their sales pitch.

MTV

Ya it going to get very interesting. If the rest of the world goes to a sat based system like it seems, the US may have to follow suit, at least if you guys want to cross any borders. And will our sat based system work when we want to come fly down there? Who knows at this point. Hopefully they dont change I and you guys all have to upgrade to 1090 systems.

mtv wrote:
Fortunately, so far, there's no place I NEED or want to go that will require ADS-B.

MTV

It may not be required but I’m always amazed at how many ADS-B targets are very close by that I still can’t see visually. That’s true flying the Hudson Corridor in NYC with 100s of targets or even up in Alaska with one or two. I’ve had too many close calls to not take advantage of ADS-B in and out.

I’ve flown with a Stratus portable, talking to my iPad, and in this part of the world, it missed a lot of traffic.

Maybe a hardwired unit would do better, but terrain is an issue. And, weather via ADS-B? Poor coverage at the heights and in terrain that I fly.

MTV

mtv wrote:Good to know on the bottom antennas. But, yes, that's what the FAA guys told me, was that everyone else in the world is going to 1090, so since most of the "small airplane" ADS-B units are 978, they wont' work on those systems. And, indeed the uAvionix units are 978......

I kinda like the UAT setup for smaller airplanes. For these reasons:

1. Your weather and terminal information comes in on 978mhz, so there is reason to build that infrastructure.
2. You get anonymous mode.
3. You don't have to buy another transponder if the one you have already works fine.

That said, the platform is a mess, and I wouldn't be surprised to have everything change again in the next 10 years.

I've been leaning toward the Garmin GDL82 for when I "upgrade" to ADS-B out.
But a few things sound like a PITA:
1) locating of GPS antenna / receiver up on top, has to be 36" (?) from existing antennae
2) fabricating coax between antenna & box, uses special (oddball size) connectors
3) fabricating USB-to-mini/micro/whatever connector, so laptop can program GDL82
4) locatiing of box, needs to be downstream of txp and near txp antenna -- under floor maybe?

So the Uavionix "Tail Beacon" is looking more & more attractive--
just remove tail nav light, plug I and install unit, wirelessly program it (with smartphone?), and go flying.
Cost is about the same either way, $2K or so.

mtv wrote:I’ve flown with a Stratus portable, talking to my iPad, and in this part of the world, it missed a lot of traffic.

Maybe a hardwired unit would do better, but terrain is an issue. And, weather via ADS-B? Poor coverage at the heights and in terrain that I fly.

MTV

Hardwiring gets you about 10-15% improvement on signal quality over a portable unit. In MT terrain it might help a bit if you're on the fringe, but radio will always suffer line of site issues. ADS-B helps mitigate that by littering the countryside with towers instead of comparatively few RADAR stations, however if you fly between the peaks in mountainous terrain you will always have shadow areas where it won't work.

Traffic only really works if you can receive the towers or another aircraft's response - again limited potential in your area. Some transponders add an 'active' mode to query other aircraft directly, and that is something which might benefit you but only if the other aircraft actually has a transponder too. While ADS-B has found aircraft for me that I never knew existed, eyeballs are still the best traffic avoidance in many parts of the world.

You nailed the issue with weather. XM isn't free, but is available pretty much anywhere. I've been contemplating one of the GDL-52 receivers for that reason, then I can go from two boxes to one and get the best of both worlds. As I will likely install a Stratus ESG transponder soon, I can also plug the GDL into the ESG's external receiver port and utilize the aircraft's hardwired antenna for a portable ADS-B receiver. It's about the most capable setup I can come up with. Both devices combined are about $4k (incl. the GDL rebate through year end), and FAA just announced the ADS-B rebate is back so $3500 for an In/Out+SXM weather+WAAS GPS solution is really not bad.

colopilot wrote:You nailed the issue with weather. XM isn't free, but is available pretty much anywhere.

Not Alaska.

akschu wrote:

colopilot wrote:You nailed the issue with weather. XM isn't free, but is available pretty much anywhere.

Not Alaska.

Yeah interesting, I didn't realize until now that it basically just covers CONUS plus some adjacent overlap. Good for MTV, not so much for you guys up in AK.

akschu wrote:That said, the platform is a mess, and I wouldn't be surprised to have everything change again in the next 10 years.

It is a mess. But I doubt they will change it. It could have been a useful, great system. That was not their plan.

There may be some issues, but when I go flying with my buddy who has in/out like myself, it is AWESOME to be able to see each orther.
To me it makes it all 100% worth it!

colopilot wrote:

mtv wrote:I’ve flown with a Stratus portable, talking to my iPad, and in this part of the world, it missed a lot of traffic.

Maybe a hardwired unit would do better, but terrain is an issue. And, weather via ADS-B? Poor coverage at the heights and in terrain that I fly.

MTV

Hardwiring gets you about 10-15% improvement on signal quality over a portable unit. In MT terrain it might help a bit if you're on the fringe, but radio will always suffer line of site issues. ADS-B helps mitigate that by littering the countryside with towers instead of comparatively few RADAR stations, however if you fly between the peaks in mountainous terrain you will always have shadow areas where it won't work.

Traffic only really works if you can receive the towers or another aircraft's response - again limited potential in your area. Some transponders add an 'active' mode to query other aircraft directly, and that is something which might benefit you but only if the other aircraft actually has a transponder too. While ADS-B has found aircraft for me that I never knew existed, eyeballs are still the best traffic avoidance in many parts of the world.

You nailed the issue with weather. XM isn't free, but is available pretty much anywhere. I've been contemplating one of the GDL-52 receivers for that reason, then I can go from two boxes to one and get the best of both worlds. As I will likely install a Stratus ESG transponder soon, I can also plug the GDL into the ESG's external receiver port and utilize the aircraft's hardwired antenna for a portable ADS-B receiver. It's about the most capable setup I can come up with. Both devices combined are about $4k (incl. the GDL rebate through year end), and FAA just announced the ADS-B rebate is back so $3500 for an In/Out+SXM weather+WAAS GPS solution is really not bad.

The big advantage of XM Weather: You can see the weather on the ground BEFORE you launch. Never happen with ADS-B weather.

And, yes, terrain is the issue here with regard to traffic and weather. And, I rarely fly above the ridges.....not much to see up there.

Finally, looking for traffic on an iPad on a kneeboard takes eyes away from the windows, where they should be. If I had a decent MFD, traffic might be useful, but I’ve flown planes with large MFDs and traffic, in some busy areas, and spent most of the time looking for ADS-B traffic that really wasn’t a hazard anyway.

In busy airspace, I want eyes outside, thank you.

MTV

I think the one feature missing from ADS-B traffic data is the system being able to tell me which of the 15 targets on the little screen to care about.
Flying VFR in the DC SFRA, you can have 15 or 20 aircraft swirling around a 5 mile radius of you and all of them at 1,400' to stay under Class B. The second most common thing for Approach to tell me on the radio is "traffic, opposite direction, same altitude, skyhawk..."
I've seen ADS-B traffic alerts in pattern for a plane on the ground doing a run-up.... It basically stays on all day long but never tells me which ones are converging with me? So, the whole system gets ignored when there could be some actual value there.

Instead of the system alerting me to the presence of every aircraft in a 5 mile radius, I want the thing to tell me that I can ignore all but THIS one (or none) so I can keep my eyes outside looking for the other one that doesn't have ADSB or the nutjob with a 15 pound drone.

Sailplanes had this figured out years ago with FLARM.