ADS-B

[jethound]

I have dual Dynon SkyView with the ADS-B, I also run an IPAD with a Stratus 2.
On a couple of recent trips from Atlanta to Columbus, Ohio I have been told of traffic that shows up on the stratus but not on the Dynon display even though it states the we are in the Full mode on the ADS-B
Other times when the Dynon states Partial, I am receiving a lot of traffic on the Stratus. Why is an portable unit out performing the Dynon ADS-B?

IFR traffic has been called out above my altitude by 500 feet and they still do not show up on the SkyView.

Any ideas.

 

[rvator51]

I wonder if this is because the Stratus 2 had dual antennas and it is picking up the 1090 freq air-to-air traffic?

 

[vlittle]

ADSB traffic is NOT sufficient for anti-collision functions. Even the superior Stratus implementation cannot detect mode-a or mode-c traffic. The Stratus FAQ says "Remember, ADS-B traffic, even at its best, is not a complete picture of nearby traffic and is not a substitute for looking out the window when fulfilling your responsibility to see and avoid."

ADS-B is primarily for the benefit of ATC, sitting comfortably on the ground. For a better view of traffic, TCAS is a superior and vastly more expensive solution.

A good compromise would be a Skyview ADS-B in receiver and a passive radar traffic monitor or a Stratus ADSB-in dual mode receiver and a passive traffic monitor. I'm not aware of a device that provides mode-a/c/s detection plus ADSB-in (UAT or TIS-B). Pondering the problem, just a stand-alone passive traffic monitor will provide more traffic info in your immediate vicinity than ADS-B.

Making everything worse, when you cross the border into Canada, only Mode-a/c/s passive detection will work.

Vern

 

[rvator51]

Hi Vern,

I thought that ATC also sends the mode C traffic to your UAT receiver in their ADS-B transmissions? Is that not true?

Regards,
Tom

 

[flybuddy]

I've found the opposite true, occasionally I don't get on Ipad but always get on Skyview. I assume you have an ADSB out transponder also?

 

[lolachampcar]

Assuming no other ground illumination of the ADSB station, the ground station will send Skyview the traffic it can not see.  In SV's case, you are illuminating the ground station with S-ES data so the ground station knows you can hear S-ES data and will only send you UAT based and non-ADSB targets.

As flybuddy has mentioned, I've also found Dynon's solution to be superior but that is only my experience.

 

[jethound]

We have the out and in capability on the ADS-B. Utilizing the dynon s mode transponder.
We get while flying above 5000 feet mostly full ads-b on the bottom right of the Dynon Display. I saw a web site address where we can get an actual faa print out of our devices.
I am really praying Dynon comes around and develops a certified GPS for all the folks that currently have the ADS-b capability. I realize this is a major investment but could also be a stepping stone for a future GPS nav unit. That would blow Dynon to the forefront.
Jack

 

[vlittle]

Hi Vern,

I thought that ATC also sends the mode C traffic to your UAT receiver in their ADS-B transmissions?  Is that not true?

Regards,
Tom

Only if they can see you AND the traffic. If you or your traffic is in the radar shadow of nearby terrain, you may be on your own. If the nearby traffic is pinging 1090 ES, a passive monitor or a 1090 ES receiver will pick it up. Overhead airliners TCAS can also excite Mode A/C when ground radar is obscured.

The degenerate case is when you are flying in a remote area with no radar coverage and no TIS-B uplink. You will have no traffic displayed on your ADS-B receiver unless it supports 1090- ES IN and/or passive Mode A/C. Even then, traffic can be invisible if it's ADSB-OUT is a UAT, not a Mode-S/ES transponder like Dynon's.

It was a mistake for the FAA to allow ADSB-OUT using a UAT. If they had mandated Mode S/ES For ADSB-OUT, then all aircraft could be made visible to each other without radar groundstations in remote areas. Using a 1090-ES receiver or a passive monitor would then work everywhere after 2020.

Vern

 

[jethound]

Vern, that is a great thing. The UAT was touted for the weather/ radar capabilities which is great. I wonder how much more expensive the ADS-b would have been with the 1090 squatter included. Then we could fly out of the country after 2020 . It would be great to have a Dynon Upgrade.
Jack

 

[rvator51]

Thanks Vern. I hope Dynon considers a dual channel uat receiver option in the future. Are there any passive monitors still being sold? The only I knew was Zaon and I heard they went but of business.

 

[dynonsupport]

Vern,
It's funny how 10 years ago, nobody had traffic, and we were OK. Now, if you can't see the guy down deep in the canyon, it's dangerous somehow. Amazing how attitudes change just because technology makes something feasible.

The FAA did not make a mistake in allowing 978MHz ADS-B out. There is no ADS-B OUT mandate in the USA in remote areas. It's perfect legal to stay out of Class C/B areas and never equip with Mode-S (or a transponder at all). Thus, the only point of ADS-B out was to be used in dense areas, where both ADS-B ground stations and primary radar coverage is available.

The only way to overcome this would be to make it illegal to fly without a Mode-S, ES out, certified position source on board. How well do you think that would go over? Given that the FAA has pushed that more than any other country, calling our implementation wrong seems kind of silly. No other country in the world has a system as capable as ours.

There's only one way for a traffic system to be dangerous in a plane, and that's for the pilot to rely on it 100%. I don't care what system it is. Passive systems rely on overhead airliners to interrogate GA aircraft, which rely on those planes having transponders that are on, and then all you get is error-ridden distance and bearing info. Traffic is always only for enhanced situational awareness.

Dynon is leaps ahead of many of their competitors here as well - our system shows you when you have radar coverage and when you don't. At least with this you have a sense of how solid your coverage is.

Dual channel is a possibility in the future, but it's far from the 100% solution. You can only pick up Mode-S w/ES transponders with that. In Seattle only about 5% of the planes are equipped this way, and 1/2 of those are Boeings (the other half are SkyViews!) Remember that you can pick these up anytime you can see an ADS-B ground station, radar coverage or not, and it's getting harder and harder to find ADS-B voids unless you are low and deep in the mountains.

 

[vlittle]

I was not criticizing Dynon here.  The technological limitations of ADS-B have been in my crosshairs for years.  I hope pilots are not depending on traffic information to replace see and avoid, which is how this discussion started.

I have used passive traffic monitors since 2005 and I have found that it's like a second set of eyes... Not infallible, but much better than a human at picking up conflicts.  ADS-B shares similar limitations but comes at a greater cost.

The mountain valley effect is quite real... Mountain passes tend to concentrate traffic.  It got so bad up here that we installed multilateration sites between Vancouver and Whistler Mountain so that traffic could be managed during the Olympics.

It's frustrating that we have a perfectly good technology, 1090ES that could have been the solution for all transponder equipped aircraft, as it is in Europe **edit, Europe is not so smart, they don't do this**. It's that darn UAT Out option that's messing things up. 

I guess the moral of my story: Use a SkyView 261 transponder for ADS-B OUT.

 

[dynonsupport]

Vern,
Europe doesn't have a Mode-S ES mandate. Only Mode S. Notice how Garmin sells the 328 transponder which is Mode-S without ES for 30% less than the 330? That's all for Europe.

Thus, basically zero GA aircraft in Europe broadcast their position, and the only useful traffic in Europe is passive.

 

[vlittle]

I stand corrected. The FLARM technology is what Europe is commonly using.

 

[Dynon]

I have dual Dynon SkyView with the ADS-B,  I also run an IPAD with a Stratus 2.
On a couple of recent trips from Atlanta to Columbus, Ohio I have been told of traffic that shows up on the stratus but not on the Dynon display even though it states the we are in the Full mode on the ADS-B
Other times when the Dynon states Partial, I am receiving a lot of traffic on the Stratus.  Why is an portable unit out performing the Dynon ADS-B?

IFR traffic has been called out above my altitude by 500 feet and they still do not show up on the SkyView.

Any ideas.

So a few thoughts on what you're seeing here. First, this isn't documented (but probably should be), but we declutter the ADS-B traffic portrait a bit so that you're not seeing aircraft that are really far away (>15nm), and additionally aircraft that are more than 5k feet away from your altitude. The latter helps get ride of the layer of airliners that you'd otherwise see.

Next - when you have FULL status, you should seeing all ADS-B targets, regardless of the band they're on (because the ADS-B ground system rebroadcasts the ones you can't see directly), as well as other Mode-C equipped traffic that the FAA's picking up via radar.  When you're in partial, you may not have ground station reception (or the FAA may not have radar coverage in the area), and in those cases, you'll see less traffic. As we said earlier, many of these are airliners that are probably not near your altitude.

When you were getting the call out of traffic that was 500ft above, how far away was it? Do you happen to remember if you were ADS-B FULL at that time?

As other people have said, side by side comparisons generally favor SkyView in our experience, but in any case, if you happen to observe this phenomenon, can you grab some dueling pictures of what you're seeing on SV and your ipad?

 

[lolachampcar]

I'm a big fan of ADSB and have posted a lengthly note elsewhere.

It seems to me the best solution would be for the FAA to grab this opportunity and run with it.  The 2020 mandate is coming and yet costs and installation hurdles will keep a lot of people from complying and likely delay or even kill the mandate.  That would be a shame.

The FAA needs to show leadership on this issue and act in the public's best interest by removing the impediments to making ADSB a reality.  I would start with these steps-

Canvas manufacturers to define a piece of equipment to include WAAS GPS, Altitude Encoding, Mode S-ES and UAT In.

Go back to those same manufacturers and have them define their cost structure so as to identify non-value cost adders.  These include certification costs, manufacturing documentation costs and liability.  I think we can all agree that a Mode S transponder with a SMM pressure sensor and GPS puck would not be that expensive to produce if the volume were good and there were no regulations.

Use the power of the mandate to remove the non-value cost adders WITHOUT affecting quality or performance.  The FAA can literally establish a zero cost test facility with the task of ASSISTING manufacturers in certifying their equipment.

Use congress to remove the tort related non-value cost adders.  "If it meets this spec as tested by us and manufactured as described then your liability is limited to XYZ".

Define a straight forward path to install (337 for certified) and test for functional compliance such that the EAB guys can do it themselves and a simple A&P can do it on certified (ala transponder swap, C for S currently).

Most of this is within the FAA's prevue with the exception of the tort reform element.  It can be done.  The result is a $1500 piece of equipment that has all GA squawking their location in the US and (assuming a bluetooth or wifi capability) everyone has traffic and weather on their carry on device (certified) or PFD (experimental).  All of this can be done without touching the third rail that is experimental PFDs in certified aircraft.

 

[jethound]

I have noticed various limitations on the Stratus 2 even in our corporate jet. We have TCAS II vs7 and many times traffic on the TCAS display just is not on the Stratus.

AS far as answering the question. We were at 5 miles separation with Huntignton, Approach the traffic was closing in from 10 oclock. But we did not paint him on the Dynon unit.

We will continue to grow in knowledge about the Dynon ADS-B as well as the Stratus.

Jack