On Oct 6, 10:31*pm, tomlusch
wrote:
;663552 Wrote:



Continuing problems seeing ATCRBS transponders with Mode S
interrogators

Hey all, I work in, lets call it 'an associated industry' and we are
still seeing ATCRBS transponders that reply to some interrogators, and
not to others.

At one time this was known as the 'P4 problem', sometimes as the
'Terra problem', just want to ask if anyone out there flying with an
ATCRBS xpdr is still having trouble being 'seen' by some
interrogators, but no problem with others.

Thx-

Dave

Funny that you should pose such a question Dave. *Just yesterday
evening I observed a primary target with our ASR-9 (Mode S) moving ENE
at a decent clip. *Used a different display and selected our nearby
ARSR (an ATCBI-6) sensor, and saw a rock solid beacon reply, showing
that it was an aircraft at 13,000 ft msl. *Never did see a transponder
return using our ASR-9. *

Take a look at my previous experience with this type of transponder
behavior...

http://home.columbus.rr.com/lusch/talotta.html

..and get in touch with me. *

Tom Luschhttp://tomlusch.com

--
tomlusch

Hey, Tom. Yeah, I'm familiar with your reports on this / these issues,
back when I was building a simulation model of transponders.

Seems there are some really old transponders out there, or
'some' (heh) that just don't meet spec.


Dave