The place for technical discussions about GA and flying.
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By GliderV
#1671039
I have a Funke TRT800H and would like to it to connect a GPS source for ADSB out. What GPS standalone unit unit would do the job? I have a Power Flarm but the mix of various NMEA data seems to rule it out as a source.
Thanks
User avatar
By Paul_Sengupta
#1671054
First thing to do is to check serial numbers and software versions. Some versions of that transponder need upgrading and Funke charge a few hundred quid to do it.

Secondly, any NMEA source should work. There have been a number of people who have used a PilotAware with a Funke transponder to provide ADS-B out, so, assuming (1), I don't see why the output from the PowerFlarm shouldn't work, but I'm unfamiliar with the unit and it could, as you say, be outputting a mix.

If you want a standalone one, you could do an e-bay or Aliexpress search for RS232 GPS.

Or invest in a PilotAware! :D
By Xic
#1673134
I received an email from IAC about a problem with ADSB out and aerobatics. Just spent a few minutes on the IAC website looking for an update and could find nothing on the subject at all.

What gives?
By riverrock
#1673168
Basically - GPS can't keep up with aerobatics. It uses a prediction algorithm to work out where you are, and also as a self check (so if your location suddenly jumps, it thinks it is no longer accurate). Therefore ADS-B out would no longer send position reports (or reduce reported accuracy level significantly). This is part of being SIL-1 (it needs to be sure of its own accuracy).

It will take some time of "normal" flight for a GPS position source to decide that it is accurate again. This will cause issues in the USA where they plan to get rid of secondary radar, relying only on ADS-B, GPS based position reports.

See here for an old update from them: https://www.iac.org/news/2016-12-17-ads-b-update which describes the issue. There isn't an easy way round it.
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