Many transponders in close proximity

jettester wrote:

#11. A transponder may have helped the Hawker to receive a TCAS warning
if ATC could "see" the glider transponder (line of sight), Mode C would
have reported its altitude, and MTI did not filter because the glider
was not circling. I confirmed that MTI is set 65K in this area.

Jettester (UP)


TCAS does not depend on the target aircraft responding to ATC radar.
TCAS itself performs the interogation and processes the response
independent of ground radar. Since ground radar is not required, the
MTI settings of a proximate ground radar have no influence of the
visibility of the target to a TCAS equipped aircraft.

TPAS however, does rely on the target responding to someone else.

I'll provide one reference that supports my contention. Can you
provide any that support yours?

to quote from http://www.nak.no/flynytt/download/TCAS_II_V7.pdf

Target Surveillance:

TCAS, independent of any ground inputs,
performs surveillance of nearby aircraft to
provide information on the position and
altitude of these aircraft so the collision
avoidance algorithms can perform their
function.