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Nav Canada requires diversity 1090ES ADS-B

jliltd

Well Known Member
"Most U.S. general aviation operators will not be able to fly in Canadian controlled airspace and vice versa when Canada mandates ADS-B, according to Nav Canada", Avweb reported this morning. Canada will require ADS-B equipment to be "diversity" type due to that countries adoption of Aireon sattelite tracking instead of ground-based stations. Diversity means the equipment uses two ADS-B "out" antennas. The most common belly-mounted antenna along with a second top-mounted antenna. Both being transponder type antennas. There has been speculation about this until Nav Canada's recent statement confirming this.

So what impact does this have? If any Canadian aircraft have already equipped with the likes of a GTX 335/345, 45R, 345R or even the brand new GTX 375 GPS/Txp they are not ADS-B compliant for Canadian rule airspace. Same applies to visiting US Aircraft. The same applies to any other manufacturers' ADS-B out equipment without diversity.

That's a fine kettle of fish. The same could be coming to the UK since they too use the Aireon sattelite for tracking.

Jim
 
Accidentally looking smarter than I am?

This sounds like an example of procrastinators fortuitously coming out better than early adopters.

That seems to be a thing with avionics in general.
 
It's hardly a done deal, so don't start to panic yet. COPA and others are lobbying for a more sane approach, in which private aircraft are not required to have diversity antennas. It's been shown that a belly-mounted antenna can adequately communicate to satellite based receivers provided they are not directly overhead. As the Aireon system is based on a network of satellites, like GPS, you'll regularly have satellites off to the side that your belly-based antenna can trigger.

As this is not a guarantee, and there *will* be times in which your belly-based antenna could conceivably get blocked by your fuselage, nobody is willing to allow a belly-only solution for commercial flights. But it may be acceptable for private aircraft operating below 12,500.

As with the 406MHz ELT debaucle, nothing has been legislated yet. Unless you want to be an early adopter, avoid the purchase decision as long as you can. Keep in mind that Aireon has the potential to replace the 406MHz ELT system as well.

The same could be coming to the UK since they too use the Aireon sattelite for tracking.
FWIW, the US is the only country that's using a ground-based system. The entire planet (including the US) is covered by Aireon.
 
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Russ Niles wrote that article based on a sample size of... ONE!
That's ONE enquiry to Nav Canada, to ONE person there, and ONE response.
Sorry, but I ain't spending thousands on a new transponder on the basis of this article.

Also, note that larger airports are most likely going to continue to have primary surveillance radar, to which is attached Secondary Surveillance Radar (SSR), the device that interrogates our transponders. I strongly suspect we will see a move toward a 1090-ES ADSB-OUT mandate for flight within the coverage volume of SSR (large airports), with a requirement for a belly-mounted antenna at a minimum.

Any requirement that all GA aircraft be equipped with a Diversity transponder will likely result in many GA aircraft being removed from the civil registry.

Russ was likely right in his comments with respect to 978 UAT for ADSB-OUT - it most likely will not be supported for use in Canada.

As Russ pointed out, keep in mind that NAV CANADA doesn't make the rules - and thank goodness for that fact, otherwise there would be no GA in Canada since NAV CANADA is essentially the airlines' lap dog.
 
I'm a bit mystified by the whole 'top/bottom' antenna thing, anyway. Unless you're right on top of a ground based ADSB 'unit', top would work just fine, just like it does for a/c radios. So why not just use top mount, if needing to hit both ground and sat based units?
 
how big are the antennae?

ok radio guys....just how big are these antennae?( and ground plane?)
I seem to see little 4" blades on the bellies of most aircraft, so why all this " top-bottom" issue? can't we put these things in a wingtip under a fibreglas fairing?
....or...ahem, (for Mark and me) in the fuselage of some certain composite aircraft? ;-)
 
I'm a bit mystified by the whole 'top/bottom' antenna thing, anyway. Unless you're right on top of a ground based ADSB 'unit', top would work just fine, just like it does for a/c radios. So why not just use top mount, if needing to hit both ground and sat based units?
Very true. Or you can put your RV flying skills to use and fly inverted while inside Canadian airspace.

altman-top-gun.jpg

"Honestly sir, I just crossed the US/Canada border!!" :eek:

ok radio guys....just how big are these antennae?( and ground plane?)
I seem to see little 4" blades on the bellies of most aircraft, so why all this " top-bottom" issue? can't we put these things in a wingtip under a fiberglass fairing?
....or...ahem, (for Mark and me) in the fuselage of some certain composite aircraft? ;-)
In this particular application, Fiberglass=Yes, Carbon/Fiber=No.

:cool:
 
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ok radio guys....just how big are these antennae?( and ground plane?)
I seem to see little 4" blades on the bellies of most aircraft, so why all this " top-bottom" issue? can't we put these things in a wingtip under a fibreglas fairing?
....or...ahem, (for Mark and me) in the fuselage of some certain composite aircraft? ;-)

Maybe this is the explanation you?re looking for:
These antennas (think of the 4? vertical ?stick?, usually with a ball on the end of it, mounted on the bottom of the metal fuselage) are a fair approximation of an ideal, quarter wave radiator over an infinite, ideal ground plane, for radiation going down below the aircraft. But the ideal antenna will radiate nothing above the ideal ground plane (nothing upwards), while real-world antennas will, mostly due to the actual ground plane being rather small. The problem is, it is very hard to accurately predict or calculate how well any given antenna will perform in a direction where the ideal antenna radiates zero. So the rule-makers base their calculations on the assumption that real antennas will perform poorly in directions where ideal antennas radiate zero.
A half-wave dipole, mounted vertically in a fiberglass airplane, should perform just as well as two quarter waves, one on top, one on bottom. But putting a vertical dipole out in the wingtip is too unpredictable, if there is a metal end rib a foot and a half or so away.
 
Any requirement that all GA aircraft be equipped with a Diversity transponder will likely result in many GA aircraft being removed from the civil registry.
That wouldn't be necessary in any case. A non-diversity transponder with the antenna pointed up would be just fine... In Canadian space.

As Russ pointed out, keep in mind that NAV CANADA doesn't make the rules...
Well, they don't approve the legislation. But as the sole provider of services and the ones deciding what the hardware launched into space will do, they are at least a very strong influencer of what the rules will look like. Transport has abdicated most of their responsibility for airspace to them, and generally is following their recommendations on direction moving forward.
 
Well, a few months before the mandatory equippage for ADS-B in the US, it is now functionally obsolete! UAT will stand alone for a while, but my opinion is that any new aircraft should be equipped with a 1090 ES transponder and diversity antennas, or the equivalent.

MicroAvionics is the company to watch here for cost-effective solutions. It is my anticipation (based on conversations with the company) that they will offer something soon.

For example, a dipole antenna located in an extended rudder stinger may be fine for RV?s (with appropriate structural engineering). Coupled with some regulatory changes, this may be just fine.

As for transborder operations.... we have a virtual barrier already. We don't recognize American medical reforms in Canada, for example.

Sigh.
 
As for transborder operations.... we have a virtual barrier already. We don't recognize American medical reforms in Canada, for example.

Sigh.

Double sigh since the US doesn't recognize the Canadian Owner Maintenance class of aircraft. Disappointing for all involved, on both sides of the border.

WRT the uAvionix solutions, one thing that is worthy of note is that a transponder mounted on the tip of the rudder (as an example) should be "visible" to receivers both on the ground and in space if its antenna is properly optimized.

If a diversity transponder mandate comes out I'm hoping uAvionix and Trig will come to the table with appropriate products. Fortunately I operate a "plastic" airplane so for the time being I'm not worried about Aerion satellites being able to see my transponder. I did opt to go with a 1090ES solution out of the gate for US rule compliance, simply because I knew Aerion was coming and would not support 978 UAT.
 
Well, a few months before the mandatory equippage for ADS-B in the US, it is now functionally obsolete! UAT will stand alone for a while, but my opinion is that any new aircraft should be equipped with a 1090 ES transponder and diversity antennas, or the equivalent.
I'm not sure "obsolete" is completely fair. The UAT ground broadcast will still be useful for rebroadcast traffic, weather, NOTAMS, TFR's, etc. Aerion is a uni-directional system, the satellites are receive-only as far as we're concerned. All data goes back to ATC for traffic monitoring, no information is rebroadcast for the benefit of other aircraft in the sky.
 
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