On Dec 8, 11:21*am, Richard wrote:
On Dec 8, 10:24*am, Ernst wrote:

Is this an alternative?http://www.sandia.aero/?q=STX165

Ernst,

Other than it is square, it looks like a good option.

Craggy Aero will be selling them. *They will probably be available
around 2/1/2011 and will be priced less than $1700.

Specs look similar to the higher powered Trig and it really is a one
piece transponder.

Thanks,

Richardwww.craggyaero.com

OK I'll play this game. The specs look *nothing* like the Trig TT21/22
starting with...

1. This is a Mode C not a Mode S transponder.

2. The brochure lists 500mA power consumption at 28VDC. Assuming
perfect power supply behavior that translates to 1.1 A current draw at
12VDC. That is more than the total power consumption of many gliders.
A Trig TT-21 in a test righ being hammered with a high rate of
interrogations (similar to the rate used in the specs of the
transponder here) measured 325mA @ 12VDC. In practice owners of the
TT21 are seeing power consumption below 300mA. Richard this can't
possibly be right or the transponder will be utterly useless in
gliders - since you are planning on selling them what is the correct
power consumption at 12VDC.

3. They claim this is targeted at gliders and others uses, yet they
picked a mounting rectangular mount form factor pretty incompatible
with the standard 57mm hole (The Trig TT21 uses that hole or a smaller
rectangular cutout) the transponder mention here is a huge 1.78”H x
3.5”W (case dimension, panel cutout smaller).

---

Hang on, I feel it coming,...

WHAT THE !@#$? A $%^ DAMN BLOODY BOAT ANCHOR PIECE OF CRAP MODE C
TRANSPONDER!

(phew, now I fell better).

Why would any company in their right mind start building Mode C
transponders in the age of ADS-B data-out mandates in the USA? And
Mode S mandates in place already in Europe? Why would any purchaser in
their right mind purchase and install a Mode C transponder when the
Mode S Trig TT21 is available, is smaller, uses less power, is well
proven (good adoption esp. in gliders, used by the FAA for ADS-B
surveys, OEM'ed by Dynon, etc.) and provides a path to do 1090ES data-
out. Especially for the glider owners interested in a PowerFLARM the
Trig TT21 is currently by far the best option. There are other compact
affordable Mode S transponder options in Europe but none others
available in the USA at the current time. Maybe that will change over
time, competition is a nice thing.

The USA Mode C transponder market deserves to go away and die. If
(like me) you have one now it will keep working find and doing great
stuff for visibility to ATC and TCAS etc. for the foreseeable future
but it gives you no ADS-B data-out option. And specifically does not
give you 1090ES data-out that gives you direct long-range (much longer
then PowerFLARM-PowerFLARM) visibility to PowerFLARM receivers or
allow use with PowerFLARM for receiving ADS-R and TIS-B services.

There is absolutely space to argue that UAT devices can be used to do
ADS-B data-out to add to existing Mode C equipped aircraft (especially
for power aircraft to meet the 2020 carriage mandate) but I see no
justification for purchasing new Mode C transponders when there are
well priced and much more competitive Mode S transponders available
that provide that ADS-B data-out path (and in this case are much more
compact, easier to mount and appear to consume a lot less power).

Darryl