Fast Lex says:
My vhf aerial is fixed with a cranked bracket fixed to the side of the mast. Nothing had to be modified. The aerial I used was www.force4.co.uk/481/Vtronix-Whipflex-Antenna.html. This aerial has a neat system for connecting the cable to the aerial which does not need soldering. I have had lots of problems with other aerials but not from this type. Just in case you are buying an aerial remember for installation at the top of a mast the aerial gain should be 3db. I also have a NASA wind direction and speed sensor on a similar bracket on the other side of the mast. Sorry no photos available.