bushy,
If you can get Dick Smith to support the Low-Level Phase of the ADS-B project in Australia then you will be able to check your transponder at Birdsville by calling up ATC with a request for a transponder check.
Always have installed, and, always switch on your transponder. Some day it will save your life when a higher performance aircraft picks you up on it's TCAS and takes avoiding action.
If we can get Dick Smith to support and call for the mandatory carriage and operation of transponders by all aircraft operating in Class G airspace, a lot more lifes will be saved.
If you don't believe me, ask an RFDS pilot.