Hello,
Sorry to jump into your exchange ... You may consider trying a Prox
alert R5 which monitors up to three threats simultaneously.

Don't ask me to elaborate online on other devices since i work for
Prox alert.

As we are an honest company we have no problem to offer a 30 days
money back
guarantee. www.prox alert.com (HQ in Phoenix AZ)

We will be happy to answer your technical questions about affordable
collision avoidance devices.

Thierry

(FISHnFLY) wrote in message . com...
I couldn't speak for the 200 model to be honest with you. The model I
got is the ATD-300. I watched it closely for a while and it was very
hard to understand what it was tracking. The NM half would show
anywhere between 5 to 0 and the altitude would jump around a lot. At
times it would appear to be functioning correctly, but then it would
go back into a very random cycle of range and altitude. If I turn off
my transponder it appears to settle down a bit. It may be having a
hard time trying to hear my transponder, but I can't tell for sure.
At one point I watched a twin Cessna fly within a half mile of me and
about 200-400 feet above me, but the only thing I got on the display
was that it was somewhere between 4 miles and 0 miles and above me 100
feet, then it would report below me 300, then show *my* altitude with
no range. Most of the time the range would change from 4 or 5 miles
to 0-1 miles within 5 to maybe 10 seconds. I think the ATD-300 is the
lest expensive out there, doesn't appear to be very accurate in WHAT
it displays.


"James M. Knox" wrote in message ...
(FISHnFLY) wrote in
om:

Has anyone flown with any of these new "portable tcas" devices? I
recently got a Monroy ATD-300, which is the lowest price, that gives
range and altitude, but have been very disappointed in the
performance. My experience is that the altitude and range of aircraft
it is reporting are constantly changing drastically.

I haven't had a chance yet to put an ATD-300 through it's paces, nor to
compare it to the latest new crop that have come out in the last few
months. I do have an ATD-200 in my plane and find it somewhere between
useful and toy. Toy, because it probably only identifies about 30% of
the traffic in a useful fashion (has a habit of not lighting up until
the traffic has passed G). Useful, because it sometimes does alert me
to look for traffic out in the boonies, when there hasn't been another
aircraft within 100 nm for the last 2 hours (hard to keep a good scan
going under those conditions). A large percentage of the time it gives
false alarms.

None of these are going to give you anything more than a very loose idea
of range. Any appearance of good range information is a lie -- a big
smoothing algorithm that makes it look like good data, but still may be
grossly inaccurate.

The older units did NOT do a real decode on altitude and hence might
trigger on a jet 30,000 feet above you, and fail to detect a '172 flying
200 feet below. The newer ones are supposed to pick up the transponder
altitude, but probably have trouble keeping it matched to the
appropriate target. [I develop algorithms for the military to track
airborne threat targets and it can get complicated.] Does it vary the
altitude substantially when you are pretty sure there is only one threat
nearby?



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James M. Knox
TriSoft ph 512-385-0316
1109-A Shady Lane fax 512-366-4331
Austin, Tx 78721
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