CMP radio station.
 

http://www.slv.vic.gov.au/argus/0/1/0/im/an010931.jpg

Source: State Library Victoria

"Shows van calling to radio station 3 U.Z. before going to Japan. From left: Jonny McMahon, Lt. V.P. O'Brien, Sgt. M.L. Williams and W/O Rowley Barley."

Interior:

http://www.slv.vic.gov.au/argus/0/1/0/im/an010932.jpg

Thanks for the ABC photos
 

I had found one of these in the Austrian Archive photo data base but then had forgotten what they were listed under. There apparently several different trucks used both during WWII and all the way through '52 or so.

Also thanks for finding and posting another photodata base.