Hello,
I dunno about Australia, but most Commonwealth countries are reactive when it comes to pirates.... waiting for a pile of complaints before getting out of their chair to do something about it.
How much UHF experience do you have? A good mid to high experience project for a great STL (Studio-Transmitter Link) can be had by hacking a pair of FRS handhelds. Have them just a channel or two out of band and use just enough power to maintain a clear link. Range is up to 45 miles.
One requiring less experience is hacking a Panasonic Gigarange cordless phone. No frequency or power tweaks are needed and they are already DSS encrypted and damn hard to trace without expensive equipment many are unlikely to bring out of the closet unless they want your head bigtime. Range is about 1/8 mile and can be extended to about 1/2 mile with an external colinear antenna array (at 2.4GHz is miniscule).
If you're new, you'll have to get a kit or something. Haven't scoped those out as I'm too much of a tinkerer

Best advice to keep from getting busted is 1) don't operate 24/7. 2) Keep your STL off when not broadcasting... it makes a nice "homing beam" straight to your house and 3) be crazy, but don't be stupid... if what you say or play will likely offend someone (like playing Death Metal in a Bible town), you'll guarantee to start the hunt.
Peace!