I am attaching a PDF with dimensions and a three step construction guide on how to build a totally bullet proof MARINE VHF J-Pole Antenna that anyone can build for under $50 that will out preform anything I have seen or used.
This antenna is ground plane independent so can be used on fiberglass vessels or in a pinch held aloft in your hand.
I built one and used it on a 45 foot work vessel I built on the Gold Coast and it smashed Brisbane Radio some 75 km away and dominated the channel whenever it was used.
This design is VERY strong and offers good channel coverage and longevity of service.
You will need a Vswr Meter to tune it - borrow one or ask a friendly local Amateur Radio Hobbyist to help tune it - its not hard to build and tune and in my opinion will end up the best antenna you ever had.
Marine Grade Aluminum Tube and Rod are readily available from any Aluminum Supplier and is as cheap as chips to buy.
Two Stainless Steel Hose Clamps from Bunnings and a SO239 connector from Jaycar and a Waterproof Electrical Box from Ideal Electrical or Bunnings about 125mm square should do a treat and finally any two short pieces of PVC coated copper wire and bingo . . . . .
As always if you have any questions don't hesitate to ask.
7.3. Aaron formerly VK4VOX
-- Edited by Aaron on Tuesday 14th of September 2021 03:13:32 PM
Aaron doesn't mention it but I think the lengths of the rods have to be cut to the exact millimetre. I remember once seeing an article on making a Yagi antenna and having to pay a premium to the metals supplier to have the elements cut to the exact lengths.
Other than that it should present no trouble to someone to build from the details given by Aaron.
It's dead easy for any Aluminium Supplier to cut to length - my supplier does it all the time for $2 a cut - or a humble hack saw or disc cutter with a 1mm cutting disc will do the job - yes accuracy is important but not hard to achieve - I have built hundreds of these for Amateur 2 meter VHF and Marine VHF and never had any failures - thanks heaps for the comments - 7.3 Aaron formerly VK4VOX