Trig 21 GPS receiver

[Giver]

Hi i have a Trig 21 transponder using a cat5 lead to my pilotaware and it works great,   But Trig are now producing a new certified GPS  https://www.gps.co.uk/trig-tn72-gps-receiver/p-0-1978/
that i presume will allow a SIL-1 output from my transponder so i can be seen by everyone including CAT aircraft,   ( i think a worthwhile improvement over my existing system)

Again i assume it would be easy to configure my Pilotaware to allow use of the Trig TN72,
Any thoughts on the above anyone ?

[PaulSS]

I saw the TN72 as well and I have to say it has got me thinking, mainly for the 'upgrade' to SIL 1.

Giver, I assume when you say you have "a Trig 21 transponder using a cat5 lead to my pilotaware" that you are using the GPS position FROM the PAW unit to enable the extended squitter in your TT21 to provide ADSB Out (SIL 0).

Clearly the TN72 will interface seamlessly with the TT21 but what we need to establish is if (a)the GPS data from the TN72 can be 'split' to the TT21 and PAW and (b)whether it is then possible to use one of those inputs into the PAW.

I do, however, wonder whether this is over-complicating things. Maybe it's better to just connect a TN72 direct to a TT21 and then just have the normal GPS dongle/antenna connected to the PAW. In my case I'm only considering a splitter because otherwise I could, conceivably, end up with 3 GPS antennas on top of my coaming (1 EFIS, 1 PAW and, now, 1 TN72). If they work below the coaming then all will be well but I'm loath to have something akin to the Fylingdales sitting on top of my glareshield 

[exfirepro]

Ivor,

The short answer will be to remove the connection between your PAW and your TT21 and replace this with a new lead from the 9-pin D-sub connector on the TN72 which will need to be spliced into the existing TT21 25-pin D-sub connector. This presumably includes both power and data wires. I haven’t seen the TN72 installation manual yet, (though I have seen a prototype installed on a colleagues aircraft).

Sorry, I can’t say whether it is possible to ‘split’ the GPS signal and use it to also supply PAW. This might be possible, but not sure if that would affect the TN72 certification. I’m sure Trig will be happy to advise in due course. I will ask my Trig contacts about this next time I speak to them.

The only ‘configuration’ needed to your existing PAW setup will be to set the USB port you are currently using for your ‘Trig Transponder’ feed back to ‘auto’.

Regards

Peter

[PaulSS]

I've been doing some digging and I really don't think it is feasible to split the GPS output of the TN72. You could 'share' the power and grounds of the TT21 but I, personally, don't see the point. I'd rather have completely separate circuits. As far as the GPS is concerned I reckon it's a matter of having the TN72 connected to the TT21, which will then output SIL 1. If you happen to have a TT22 then it will kick out an SIL 3 and SDA 2 (i.e. certified). I'd not bother trying to use the GPS data from the TN72 into PAW but, instead, either use the GPS dongle or one of the other GPS antennas.

I'm currently researching the antennas that might be able to be used with the TN72. Their recommended one can live outside and washes the dishes but it's almost the same price as the magic box itself. This guy: http://www.cumulus-soaring.com/trig.htm#GPS-Antenna-QMAm  seems to think this antenna works but he then says he hasn't tested it  Trig say it needs an antenna with an integral amp and a gain not less than 20dB. I think I'll have to be pretty specific with Amazon 

Hopefully you'll see an attachment showing the Trig TN72 wiring diagram (at least it's very easy) and a screenshot of Cumulus Soaring's antenna: