It looks like the low cost ADS-B UAT logjam has been broken:

http://www.aopa.org/advocacy/article....mc_sec t=gan

While the price is somewhat higher than I would like to see, it's
competitive with buying a transponder coupled with a Zaon PCAS XRX. If
you are within range of an ADS-B ground station, you get much more
accurate and reliable position data for conflicting traffic, free
weather, lower power consumption, plus you are visible to ATC!!!!

The down sides: No TSO, so the unit will not currently meet the 2020
ADS-B mandates; Not visible to TCAS systems.

Check them out at Oshkosh or on the web at www.navworx.com.

--
Mike Schumann