On Wednesday, November 14, 2012 10:56:40 AM UTC-6, Andy wrote:
On Nov 13, 7:54*pm, Darryl Ramm wrote:

It sounds like you are talking about an older DO260a (the RTCA spec that defines 1090ES data-out) version of a Trig transponder or at least the documentation that came with one. If you are playing with ADS-B data-out with a Trig transponder, even if you are using a non-compliant NMEA GPS source, you probalby want to get the current DO260b firmware and setup instructions from the factory (no longer included in the manual).





Although I downloaded the installation manual, rather than using a

version I had on file, it seems I still used an out of date version.



The current version, which is available at

http://www.trig-avionics.com/library...0560-00-AK.pdf, does not

include the previously quoted text.



Thanks for the correction.





Andy

HI - (This is Tim Taylor form Freeflight Systems - we make the 1201 WAAS)
First - on the checks - the FAA looks at the message you are sending which includes both position and also integrity info. Part of the integrity info is calculated real time by the GPS and part of it is fixed based on the certification level of the equipment. The real time data includes integrity of position (horizontal and vertical) and velocity (horizontal and vertical). If any of these fall below the ADS-B rule standards for any extended period, the ADS-B ground system (the SBS) flags you as "invalid" and does not pass your info on to ATC. The data does go to the airworthiness guys at the FAA and they care about installs that are transmitting but not valid. The second thing they do is check your reported position against other data they have (radar for example) and then they compare what you are saying against what they observe. If that comes out wrong you get to hear from them pretty quick. Depending on where you are, you might also see an F-16 drop by for a look.

Bottom line - if you put this stuff on your airplane you need to meet the rules - otherwise you are at best carrying weight you don't need and at worst inviting MIB to say hi.

That said, I still would want it on any airplane I was in - when it is done right you are putting some real protection around your own ship - and ATC has eyes on you - with their computer automation ready to flag any potential conflicts.

You might also want to look art 978 (UAT) ADS-B - small and light. If you are not required to have a transponder, this is a good alternative (and if you already have on it is not affected) We do significantly reduce the price of the 1201 if it is bundled with an ADS-B radio so the price is not crazy

Sorry for the long answer