In a month i will be making a long trip to australia for a holiday.I of
course plan on bringing my Bearcat portable radio scanner.I just nned to
know is it illegal for me to bring it with me on the plane?

On every flight I've been on recently, including flights between
Australia and the USA, the use of "radio transmitters or receivers" has
been specifically mentioned as one of the the things which can't be done
during flight (not just takeoff/landing).

That said, I'm not sure if anyone would actually care...

Scott.