John Smith wrote:
Bottom line: If you want to fly above 15k in airspace where a
transponder is mandatory, then 250W is required or you will not fly
there.

Do you have a reference to the regulation concerning power requirement?
I haven't been able to find it, and people just seem to rely on the
product descriptions when I ask about it.

hough.

A side note: If you want to stick with a mode C transponder, then there
are a lot of used ones available in Europe pretty cheaply, as Europe is
mandating mode S now and everybody must switch. If on the other hand you
want to buy a new unit, then go for mode S. It doesn't cost much more,
it draws less current and it will have a much better resell value.

Can you tell me which Mode S transponder you are talking about? The ones
that I see for sale in the USA are much more expensive ($600 comparing
the 175W and 150W models of Becker; $1100 comparing the 250W models of
Becker).

--
Eric Greenwell - Washington State, USA
* Change "netto" to "net" to email me directly

* Updated! "Transponders in Sailplanes" http://tinyurl.com/y739x4
* New Jan '08 - sections on Mode S, TPAS, ADS-B, Flarm, more

* "A Guide to Self-launching Sailplane Operation" at www.motorglider.org