@ doodle max I sorry to disagree but the last lot of changes to the australian ADR state NOTHING can be mounted on a bull bar if it protrudes more than 75 mm from the tubing (ie not the post or box sections)> I know as i was pinged by a very unfriendly lady in blue in the rocks in Sydney at 6.45 one morning driving in to our loading dock. I went to court as I believed she was incorrect but in fat I was.
So all driving lights, rod holders, and (get this) antennas must not protrude in any direction (ie above or in front) by more than 75mm , makes for a pretty useless antenna at 3" long. However its perfectly legal to have items on a roof rack (not even a rated or factory built one overhanging the front of the vehicle by up to 1Meter, and no rules determining how its held on there (ever see plumbers with a load of copper pipe on just held by gaffa tape?), CRAZY!