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

Hi,

I'm gaining knowledge in ADS-B over the years. But I can't say I'm an
expert. I could use some feedback from some of the extremely knowledgeable
people that monitor this group.

I sell Trig TT22 transponders - which are FAA approved for ADS-B when used
with an approved GPS source. But currently approved GPS units are $3500+.
I have been hoping that a much lower cost GPS unit "designed to meet the
requirements..." would become available in the future - making it possible
to have FAA approved ADS-B out that meets the requirements for 2020.

This week a customer pointed out a solution - I think. It is the Garmin GPS
20A. It sells for $845. That is still a lot of money for a WAAS GPS, but
it is a lot better than $3500. I believe the antenna is extra.
https://buy.garmin.com/en-US/US/in-t...rod525504.html

The web site says that it is approved for ADS-B out in LSAs. It is not
clear to me whether it would be legal to use it with a TT22 in an
experimental, or non-experimental sailplane.

I believe that ADS-B will make our flying much more safe. I am angry that
the FAA requires $3500+ GPS units at this time. They are reducing safety.

I'm not trying to push ADS-B down the throats of anyone. I am just trying
to fill a need. Many gliders already have TT22 units and might consider
adding an $845 GPS, but not a $3500+ GPS unit.

Also, it is my understanding that "field approvals" are required when
installing ADS-B out systems in certificated aircraft. Would there be a lot
of expensive paperwork necessary to get FAA approval for a system that
includes a TT22 and Garmin GPS 20A?

Any thoughts?

Best Regards,

Paul Remde
Cumulus Soaring, Inc.