I spoke to Trig at Aero Friedrichshafen, about using the TN72 as a WAAS GPS source for a TAS605A traffic box.
Unfortunately it doesn’t do the “Garmin RS232 WAAS GPS” protocol.
The TN72 GPS data is not the same as you can output from the Garmin/Avidyne units. It is a unique Trig protocol, and would not be compatible with TCAS 1. The data is basically an extended version of NMEA. The best use of the TN72, is for voluntary ADS-B Out. You can connect it to your Trig transponder and output high integrity ADS-B Out.
Presumably the Trig transponder will output SIL=3 with this…
I had an interesting discussion on this the other day regarding the Aspen PFD. Apparently it only does wind vectors if it is driven by an external GPS, so for a small plane which does not have one, would the Trigg device work?
I also spoke to Trig at Friedrichshafen and they said it’s only compatible with Trig transponders.
You cannot drive any other transponder or equipment that accepts a standard NMEA signal. What a missed opportunity…
If I understand the regulations correctly, isn’t it supposed to be SBAS-enabled to have non-zero quality flag for ADS-B?
No longer true, EASA issued CS-STAN Amendment 3 at AERO and now you can connect any GPS, transmit on SIL 0, making the high number of already done installations legal.
No longer true, EASA issued CS-STAN Amendment 3 at AERO and now you can connect any GPS, transmit on SIL 0, making the high number of already done installations legal.
You still need data stream compatibility.
Just because EASA says something is OK does not mean that a UK avionics manufacturer is going to change anything. A SIL=0..2 ADS-B OUT transmission will still be invisible to all the certified ADS-B IN installations. However this has been done to death in many other threads.
What a missed opportunity…
Yes, exactly. It appears to do SIL=3 but is basically a useless box for general purpose WAAS GPS source usage.
Please note that the Garmin WAAS data stream is not NMEA format. It is something different, not publicly documented, and has been reverse engineered by all the big names… There would be a market for an NMEA to Garmin WAAS converter which fakes SIL=3 
Waking up this thread – I have ADS-B out with the Trig TT21 and a GRT Avionics Safe-Fly 2020 which I believe is a re-badged TN72 or at least seems to be equivalent.
From what I understand, it’s fully compliant SIL=3 and seen by everyone – but not sure how I can confirm this. Anyone know? In the US there are tests that can be run. I know others with ADS-B IN see me, and I show up on all the websites, but not sure if I’m seen by everyone.
You’ll be seen by (mostly) everyone with a traffic display: certified TCAS will see your mode-S output and don’t need the ADS-B, devices like what Peter has in his plane will also see your mode-S output and don’t need the ADS-B, and everyone with low-cost ADS-B displays (e.g. PilotAware and friends) will see your ADS-B because they don’t care about SIL/SDA.
alioth wrote:
You’ll be seen by (mostly) everyone with a traffic display: certified TCAS will see your mode-S output and don’t need the ADS-B, devices like what Peter has in his plane will also see your mode-S output and don’t need the ADS-B, and everyone with low-cost ADS-B displays (e.g. PilotAware and friends) will see your ADS-B because they don’t care about SIL/SDA.
Thanks – just want to try to be as good a citizen as possible – and avoid someone hitting me.
I think this is a very good, low-cost way to get ADSB-out if you already have a Trig transponder, and I believe that there are a lot on the market.
it’s fully compliant SIL=3 and seen by everyone – but not sure how I can confirm this
An avionics shop with the right gear can check it.
Somebody with a certified ADS-B IN system (like I mention below) can also check it.
devices like what Peter has in his plane will also see your mode-S output and don’t need the ADS-B
True that I see Mode A/C/S but while the lateral position uses “DME technology” for distance, the azimuth comes from a directional antenna system which is accurate to maybe 20 deg. If I upgrade my TAS605 to a TAS605A (which I will do when Avidyne are able to supply an exchange box) then I will get a more accurate position for ADS-B OUT targets.
eurogaguest1980 wrote:
it’s fully compliant SIL=3 and seen by everyone – but not sure how I can confirm thi
You could go flying and have your assistant look at https://globe.adsbexchange.com/ for your airplane.
Select the Airplane, look at the bottom of the panel on the right-hand side.
SIL is shown as its value not the code in the ASDB message.
0=unknown, 1 = ‘<10^-3’, 2 = ‘<10^-5’ and 3 = ‘<10^-7’
