On Sep 12, 6:49*am, "Paul Remde" wrote:
Hi,

That is an interesting point. *I wonder if Trig will update the manual with
changes to the maximum altitude when the first batch of units destined for
the US (after receiving US approvals) ships.

Best Regards,

Paul Remde
Cumulus Soaring, Inc.

"jcarlyle" wrote in message

...

Don't know European rules, but the Trig TT21 installation manual says
in Table 3.1 that the altitude is 35,000 feet.

-John

On Sep 12, 8:08 am, cernauta wrote:
The factory brochurehttp://www.trig-avionics.com/library/tt21brochure.pdf
indicates that this Class 2 Transponder complies with the European
rules for "flying below 15.000 ft". Was it certified for flying up to
35.000 ft in the US? Lucky guys...

Unless I am missing something the TT21 is a "Class 2 Level 2"
transponder. The Class 2 part that means it is technically limited to
15,000' and VFR. With 130W nominal (**at the connector**) these
transponders are clearly not intended to meet the 125W ERP (Effective
Radiated Power) requirement requirement for Class 1 (above 15,000'
use).

It is anybody's guess what the "Altitude 35,000'" in the spec tables
in the documentation is supposed to mean. It is an sloppily written
spec, either way is it "Maximum Altitude?" Maximum for what? It could
be the maximum operating altitude of the electronics, ignoring the
transponder is technically not certified for use above 15,000'. It
could be the maximum range of the altitude encoder. It is anybody's
guess what it means.

This certified altitude Class 1 vs. Class 2 issue has been discussed
here before, it is something that should not be driving decisions
IMNSHO. The important thing is to install and use a transponder in
areas of high traffic/mixed jet traffic (like around Reno) and the
Trigg TT21 looks an excellent choice.

Darryl