These days, the ATC transponder shouldn’t take up a lot of panel real estate, and the new Trig Avionics (now a division of Dynon Avionics) TT23-series transponders are small enough to save at least some space. Part of Trig’s next-generation compact line of avionics, the new Mode S transponders are modular in design and have a compact digital control head (with an LCD display and built-in altitude encoder), plus a remote-mounted LRU.
The TT23 series comes in two flavors: The TT23 is made for connecting with an approved ADS-B WAAS position source, including the Trig TN70 GPS, plus third-party WAAS navigators from Garmin and Avidyne, as examples (approval is pending), while the TT23G has a built-in WAAS GPS (non-STC’d) receiver that Trig says is intended as an ADS-B Out solution for Experimental and Light Sport Aircraft. For aircraft where ADS-B Out isn’t needed, the TT23 transponder can still serve as a Mode S solution.
The new TT23 units are carry-on products from the Trig TT21 and TT22 transponder line and are 15% lighter. The TT23 has a list price of $2,865 and the TT23G is $3,255, though street prices might vary.
The trig avionics are very popular in the glider world. I considered them for my avionics upgrade and went with Stratus as my existing transponder had the flat wide casing.
Larry what’s a LRU? I’m not an avionics expert.
technically, it’s line replaceable unit, I use it synonymously with remote-mounted unit. In the case of this Trig transponder, the control head (display) is separate from transceiver.