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

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).

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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.

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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 12/20/15 5:31 AM, son_of_flubber wrote:
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.


Yes, indeed that solves the dual-link issue I have. Thanks for pointing
that out. But it kind of ruined the point of having a good long rant...
:-) But still I am far from impressed with their "oh we wanted to bring
a weather and AHRS product to market first"... uh bull**** they *were*
positioning it as a ADS-B traffic solution. Yes if you dug int the
details they warned that you needed ADS-B Out for ADS-R via the FAA
ground stations to give you 1090ES traffic data. But still there is no
excuse in my books for companies to screw around with new products that
are single link only receivers. Just a very very bad idea.

I do believe this is a legitimate attempt to do a crowdfunded device,
and BadElf has delivered nice GPS products before. I'm not questioning
them on any of that.

The question remains why not just buy a Garmin GDL39 or GLD39-3D (with
AHRS) or Status S2? Especially compared to funding a much riskier
kickstarter project for a somewhat cheaper ($549 vs. ~$900) me-too
product, vs. buying from very well established current vendors. We'll
see if they even get funded (they want $500k). Some even preliminary
specs like battery technology/life etc. seem to be not available.

It is a small sample size but effectively everybody I know who is flying
GA aircraft with portable ADS-B In is using a Stratus. I hope they are
all Stratus S2 (i.e. dual-link), but I'm not sure. That is largely
driven by the popularity of Foreflight software and their bundling with
Status.

OTOH personally much more interesting to me is the Rasberry Pi Stratux
mentioned here by Bill. (Note the dig at Appareo Stratus). That's a
great hacking platform for technical folks to play with and understand
ADS-B, the latest of several software defined radio projects (mostly for
1090ES In), but probably the most flexible. Not of any interest to me to
actually want folks to fly with... but interesting for folks who want to
play/understand ADS-B, set up ground receivers/trackers, etc.