5Z wrote:
The operating manual for the Becker ATC 4401-1-xxx transponder has the
following specifications:
(http://www.beckerusa.com/products/de...4401-1-I+O.pdf)

Max. operating altitude :
- ATC 4401-1-175 15000 ft.
- ATC 4401-1-250 50000 ft.

and

Flight level code (mode C) ICAO coding system 100-foot steps from
- ATC 4401-1-175 -1000 to 31000 ft.
- ATC 4401-1-250 -1000 to 62700 ft.

Does anyone know what exactly this means? Is the 175W unit not really
usable in sailplanes that plan to fly in the USA in areas where one
would go above 15K?

-Tom
Tom,
The 175 replies with 175 watts & the 225 replies with 225 watts. I'm
thinking the 175 is made for little bug smashers like we fly & the 225
is something you'd put into your C-210 or Piper Malibu and such. The
175 I've got seems to make the big brown turd looking Southwest jets
kinda steer around my little glider even at 12-14k. I can make my 2
sets of batteries last about 6-7 hrs and still see 11.5 v in each set
(8ah each set). I see the reply light going even on the Whites. It
will even work up to 50,000' but it's only going to reply with 175 w.
The closer you are to the antenna the better they will paint you. The
more wattage you reply with the better and further they can paint you.
I'd think that TCAS would pick either one up easily at 5-10 miles. As
far as the steps go your encoder replies with pressure altitude in 100'
incriments reliably up to the certified alt's (and probably beond but
not certified).
Russ