In article om,
5Z wrote:

On Jun 3, 2:41 pm, Andrew Sarangan wrote:
I have never flown with a TCAS, but I would think that relative
altitude and range should be enough help you see and avoid. But I do
have a question about these units. Do they work when there is no radar
facility nearby, or you are below the radar altitude?

The unit is passive, so relies on the other aircraft's transponder to
be replying to an interrogation. In Colorado, fairly low over the
mountains, one will be below radar coverage, so a VFR airplane with
transponder will not be interrogated, snd so will not be seen by the
MRX.

The unit won't see other transponders, unless the other transponder is
interrogated by a TCAS-equipped aircraft.

--
Bob Noel
(goodness, please trim replies!!!)