1. TIC TR-220 springs to mind by these people.
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2. You have to put the aircraft in the air mode, ATC Xpdrs work only in the air. Your barometric altitude should be set to QFE so other aircrafts TCAS should ignore you. You can also gag the antennas and make use of a closed hangar, which helps - but is more important if your testing TCAS at height. ie. your simulating flight.
3. A JAR 66 B2 licence is preferred.