Garmin GPS 20A with Trig TT22 in Experimental Glider - OK?

On Thursday, December 17, 2015 at 9:49:30 PM UTC-8, Mike Schumann wrote:

Gliders are currently exempt from the 2020 ADS-B rules. As a result, you should be able to use a non-compliant GPS source with a Trig21 or Trig22, as long as the Trig is compatible with the GPS's datastream. Even though the GPS source is non-compliant, it will trigger the ADS-B ground stations so that you will get TIS-B and ADS-R transmissions.

To be clear here if your glider is certified you cannot install any old GPS source. You needs to meet the FAA requirements which includes a TSO'ed IFR GPS source, discuss with your A&P/FSDO.

Unless you are a super-geek wanting to play with this stuff, just wait and see what happens with ADS-B and TABS carriage requirements for gliders.

The FAA is making it clear that non-compliant ADS-B out sources will not continue to receive ADS-B ground services in the future even if they do now. January 2016 I think is the cutoff threatened/promised by the FAA, if SIL/SDA=0 from your GPS source you will not be provided ADS-R and TIS-B ground services. And in the meantime the friendly FAA may drop you a snail mail to remind you that your aircraft is flying around with a non-complaint ADS-B Out. Having an ADS-B Out system that triggers ADS-B ground based services (ADS-R and TIS-B) won't help you anyhow if your ADS-B receiver is a PowerFLARM which receives 1090ES direct and is not capable of receiving ADS-R or TIS-B data).


This is what the Dynon Skyview systems do today. According to Dynon, this will continue to work after 2020 if you are flying in airspace where ADS-B is not required.

I expect that we will see affordable 2020 compliant GPS sources in the relatively near future. The Dynon units, which are suppose to start shipping by the end of this year, have set a pretty aggressive price point (under $600). While the Dynon module only works with the Skyview system, I was talking to an engineer at Trig a couple of months ago, who told me that they were planning to introduce an affordable compliant GPS source at a similar price point shortly after the Dynon units start shipping.

One thing that you should think about if you want to be fully 2020 compliant is that you buy a Trig21, NOT a Trig22 transponder. The Trig22, while it is ADS-B OUT compatible and will trigger the ADS-B ground stations, is NOT 2020 compliant.

Good advice, if buying a transponder now and wanting best ADS-B options/flexibility in future. But in the big picture again this may change if TABS carriage regulations happen (the TT-21 meets TABS power requirements even if it does not meet ADS-B out power requirements).

On Friday, December 18, 2015 at 11:23:25 AM UTC-8, Darryl Ramm wrote:
On Thursday, December 17, 2015 at 9:49:30 PM UTC-8, Mike Schumann wrote:

One thing that you should think about if you want to be fully 2020 compliant is that you buy a Trig21, NOT a Trig22 transponder. The Trig22, while it is ADS-B OUT compatible and will trigger the ADS-B ground stations, is NOT 2020 compliant.

Good advice, if buying a transponder now and wanting best ADS-B options/flexibility in future. But in the big picture again this may change if TABS carriage regulations happen (the TT-21 meets TABS power requirements even if it does not meet ADS-B out power requirements).

OK thanks for the private emails :-) Doh I did not spot the (likely accidental) transposition in Mike's post. To be clear the lower-powered Trig TT-21 does *not* meet the ADS-B out requirements in the USA. You need a higher-powered Trig TT-22 (and certified IFR GPS source). But as I said, TABS devices have lower power requirements so if TABS is adopted a TT-21 should be usable as a TABS device (and that includes triggering all the ADS-B ground infrastructure base services). But since there are no TABS installation or carriage regulations yet we have no real idea about any of this actually happening.

On Friday, December 18, 2015 at 11:56:18 AM UTC-8, Darryl Ramm wrote:

OK thanks for the private emails :-) Doh I did not spot the (likely accidental) transposition in Mike's post. To be clear the lower-powered Trig TT-21 does *not* meet the ADS-B out requirements in the USA. You need a higher-powered Trig TT-22 (and certified IFR GPS source). But as I said, TABS devices have lower power requirements so if TABS is adopted a TT-21 should be usable as a TABS device (and that includes triggering all the ADS-B ground infrastructure base services). But since there are no TABS installation or carriage regulations yet we have no real idea about any of this actually happening.

OK and one more... since I see this come up occasionally. The 2020 Carriage ADS-B Out regulations that require a TT-22 (if you wanted to do any install in a certified glider or a complaint install in an experimental glider) and not a (lower power) TT-21 are completely separate from the old needing a higher power (Class 1) transponder over 15,000' regulation. The TT-21 unfortunately does not meet the ADS-B Out power requirements in the USA (a unique issue to the USA because of the reliance on widely space ADS-B ground stations), even below 15,000'.

Bottom line if buying a transponder today in the USA, just get the Trig TT-22. A fine piece of kit. If you don't need a new transponder today (like you have a working Mode C transponder already, just WAIT... and see what happens with FAA regulations and new products entering the market).

I've no personal knowledge of the following kickstarter. It could be totally legit, self-delusional vaporware, or a deliberate money-extraction-scheme. It promises some subset of ADS functionality at a very low price point and may therefore be of interest.

https://www.kickstarter.com/projects...tegory_popular

I'd guess that you'd want to use it with an Iphone in a glider not an Ipad Mini.

The ADS-B receiver is really not the issue...

On Friday, December 18, 2015 at 5:26:49 PM UTC-8, Darryl Ramm wrote:
The ADS-B receiver is really not the issue...

(repost with more details, sorry the earlier one escaped)

And just becasue I can't resist a good rant and chance to kick a bad idea.... This BadElf ADS-B is a UAT In only receiver. It cannot directly "see" 1009ES Out (or TABS equipped... if TABS takes off in the USA) equipped aircraft.

OK sure, if your aircraft is equipped with this BadElf receiver and also the correct/compliant ADS-B Out that is correctly configured to advertise you have a UAT receiver and you are in range of the FAA ground infrastructure then you should receive ADS-R services that allow this receiver to "see" 1090ES Out equipped aircraft. Oh wonderful stuff (he cries sarcastically...).

But to give them credit it has pretty good naming, as this BadElf product is indeed a bad idea, just fundamentally flawed. And Stupid Elf might be an even better name. There is no excuse for a USA based manufacturer to be developing an ADS-B receiver today that is not dual-band/link layer. It just makes no sense. And with any single link layer receiver the requirements to fully participate in the ADS-B services are likely too confusing/difficult for the market/many owners/pilots to undertsand and configure correctly (anybody want to tell me how they can change the capability code bits in their ADS-B Out system so it transmits the right magic so the FAA ground infrastructure knows you have a UAT receiver so it will provide ADS-R services to your aircraft?... ah no I thought not).

I hope, for saftey reasons, that this BadElf product just will not get crowd funded/will not sell well. If it does that may reflect more market confusion than them having a great product. Why would anybody buy it when there are better, and already relatively low-cost dual-link receivers already available from much larger/proven manufacturers. Including Apparero Stratus 2S (https://www.appareo.com/aviation/ads-b/stratus) and Garmin GDL-39 series (https://buy.garmin.com/en-US/US/in-t...rod93601.html). The GDL-39 starts at less than $600. Those products directly receive ADS-B from 1090ES Out *and* UAT Out equipped aircraft, without relying on ADS-R at all. They will work outside FAA ground station range, and importantly will work regardless of whether your own aircraft has ADS-B Out installed or not. (The Status 1S is UAT In only, the 2S I mentioned is a dual link-layer receiver).

---

And in gliders in the USA we have significant PowerFLARM adoption. PowerFLARM as deployed in the USA, where it has the 1090ES In option included, does receive 1090ES directly but not UAT. And PowerFLARM has a limitation that it is not compatible with ADS-R or TIS-B--so whether you have ADS-B Out in your glider or not does not change what your PowerFLARM shows you. If you have 1090ES Out other PowerFLARM can see your 1090ES Out signal, and hopefully at significant longer ranges than typical PowerFLARM to PowerFLARM. In an ideal world PowerFLARM's ADS-B In capability would also be dual-link, but it's a specialized device mostly for the glider market and its ancestry is from Europe, and UAT, ADS-R and TIS-B are USA only silliness. I suspect the complexity of building a custom system just for the USA glider market means that just will never happen. So there is a trade off of putting good enough ahead of perfect. At least PowerFLARM has PCAS support that helps warn of transponder equipped aircraft (if they are being interrogated etc.).. which will help with UAT Out equipped aircraft which also have transponders (most/nearly all will). And anyhow I'm suspecting there will be more 1090ES Out adoption than UAT Out across the whole USA aircraft fleet as we approach 2020, and if TABS is adopted for gliders and maybe other aircraft then that is even more 1090ES Out... which all works great for those with PowerFLARM. And hopefully glider owners/pilots/FBOs/Clubs etc. have enough sense by now to know that UAT Out only devices are not good choices for equipping gliders with, or other aircraft with, that mix frequently with gliders.

There is no way of just connecting/combining say a PowerFLARM and separate UAT or dual-link ADS-B receiver. That would take significant custom software development, for a likely market of a small number of glider owners/pilots in the USA who care enough to want both FLARM and dual-band ADS-B In capability. And just having two separate systems in the cockpit is likely far too much confusion/distraction, especially trying to think about/manually deduplicate threats showing up on both systems.

---

Did somebody recently suggest not over worrying about all this stuff and just waiting and seeing what happens? Including with possible TABS installation and use regulations and adoption in the USA? Ah yes I did, several times now :-)

On Saturday, December 19, 2015 at 6:56:16 PM UTC-5, Darryl Ramm wrote:
There is no excuse for a USA based manufacturer to be developing an ADS-B receiver today that is not dual-band/link layer.

On Dec 17, 2015, Bad Elf announced what they're calling a dual band receiver. Does this address your dual band concerns?

https://www.kickstarter.com/projects.../posts/1447126

The price went up to $549 on the dual band model, but it now claims to include non-toy AHRS and a rudimentary Flight Data Recorder.

I'm not saying that this is legit, but it is interesting.

On Friday, December 18, 2015 at 5:08:18 PM UTC-8, son_of_flubber wrote:
I've no personal knowledge of the following kickstarter. It could be totally legit, self-delusional vaporware, or a deliberate money-extraction-scheme. It promises some subset of ADS functionality at a very low price point and may therefore be of interest.

https://www.kickstarter.com/projects...tegory_popular

I'd guess that you'd want to use it with an Iphone in a glider not an Ipad Mini.

And just becasue I can't resist... this is a UAT only receiver. It won't see 1909ES Out equipped aircraft directly. If your aircraft is equiiped with the correct/compliant ADS-B Out and it is correctly fofigured to dvertise you have this receiver and you are in range of the FAA ground infrastrucure then you should recive ADS-R services that allow this receiver to see 1090ES Out equipped aircraft. The exact same applies to TABS (since it is a version of 1090ES and does not transmit on UAT frequencies) should TABS be adopted in regulation in the USA and in particular for gliders.

Bottom line on this is there are excellent low cost and well proven portable general aviation ADS-B receivers from Stratus and Garmin (GDL-39 series). All these products are dual-band, i.e. driectly recve ADS-B from 1090ES Out and UAT Out equipped aircraft, do not rely on ADS-R at all, will recive both out side FAA ground station range, and imprtnatly will receive both revgarless of wether your own aidcraft has ADS-B Out or not. This Bad-Elf product just sucks, there is no excust for a USA manufatuer to be developigng an ADS-N revciver today that is not dual-band/link layer. It makes no sense, and with any silgle link layer receiver the reuqirmnts to fully paricate int he ADS-B srvicesd are likely too confusing/diffiuclt for the market/many owners/piots to undertsand and configure correctly (anybody want to tell me how they can change the capavility code bits cnfiuguration on their ADS-B Out system when they mount this reciver in their aircraft?... ah no I thought not.

And in glider land in the USA, we have for better or worse, and I think for the *much* better significant PowerFLARM adoption.
PowerFLARM does receive 1090ES directly but not UAT and is not compatible with ADS-R . In an ideal world PowerFLARM would be also be a dual-link receiver, but it's ancestry is from Europe and I suspec tthe complexity of baking a cusotm system just for the USA glider market means that would never happen.

Did somebody recently suggest not over worrying about all this stuff and just waiting and seeing what happens? Ah yes I did :-)

You no longer need to trigger ground stations to get TIS-B or FIS-B data on the UAT frequency.
I have a Raspberry Pi set up to receive UAT TIS-B and FIS-B data. Get great data with no "trigger".

BillT

On Saturday, December 19, 2015 at 8:12:21 PM UTC-8, Bill T wrote:
You no longer need to trigger ground stations to get TIS-B or FIS-B data on the UAT frequency.
I have a Raspberry Pi set up to receive UAT TIS-B and FIS-B data. Get great data with no "trigger".

BillT

You never had to do anything to get FIS-B data. It is just broadcast.

If you are seeing TIS-B messages (and are you discriminating between UAT direct, ADS-R and TIS-B?) then you are likely seeing transmissions made for client aircraft. And in some busy areas that might mean near continuous coverage. There are no ADS-R messages just transmitted blind.