On Thu, 03 Mar 2016 12:32:17 -0700, Dan Marotta wrote:


I'm gonna wait until the ADS-B requirements are better defined before
buying any equipment.

In general a good strategy. But for anyone installing or upgrading a
transponder today, paying attention to ADS-B would make sense. Putting
in a Mode S that was not upgradeable would not be advised.

Apart from that, pilots intending to fly high in the great SouthWest
should keep in mind that Class 2 transponders like the TT21 are limited
by regulation to 15,000 ft MSL. Certainly not worth it to me to save a
small amount of power and cost by putting up with a limitation like that.

-Dave