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Mode S Transponder Option

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Guido Lepore

Well-Known Member
Jul 2, 2007
Reaction score
<>I've been pretty happy with my Microair T2000SFL
transponder, which is a small 750gm 2"x2" mode C, paired with an ACK encoder.
At the time I bought it there wasn't much else available in a small size/low
power draw. I'd considered waiting for something equivalent with Mode S (that
Microair is also working on) since it appears to be coming down the pipe, but
ran out of time when our airports went to a Mode C requirement.

At the HAI convention in Disneyland this year I
found Southeast Aerospace www.seaerospace.com
selling a new small Mode S transponder from Trig
Avionics in the UK. The model is a TT21, 450 grams, built-in altitude encoder,
with a power draw of .15 Amp idle and .28 Amp active. It is similar to the
remote Becker unit in that it has the "controller head" portion that fits in
your dash in a 2 1/4" hole but is only a couple inches deep, and a remote box
about 2"x2" x 5" that locks into a small tray. Perfect for a Pitts or other
similar aircraft without a lot of room behind the panel. Price just under


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