In article , "Rob Thomas"
writes:

Yes, you will not see the traffic unless there is Mode S coverage. The
radars need to be equipped to send you the data up to your aircraft, and the
FAA has done that completely yet.


Garmin rep in a meeting last week suggested that the range is now about 60 mile
radius from equiped radars and FAA is considering extending that to 90 miles.
Problem has to do with the added work load of the radar computers handling the
additional traffic.

Chuck