"Ivan Kahn" wrote...
Before you invest in a transponder, call the facility with radar coverage in
your area and find out if they routinely "supress" VFR codes during the
times you fly. When the screen gets busy some facilities supress VFR codes,
and so a transponder would in fact be a waste of money.

A transponder will trigger ACAS/TCAS, whether or not the controllers happen to
be paying attention to it...

Marc