J Pole Loft Antenna for 2 Metres (UK)

This is just a quick build using two 1 metre lengths of M6 threaded rod that I had left over from a gardening project. After seeing them lying around in the shed, I decided to repurpose them as a J Pole antenna for the 2M band to mount in the loft for local contacts (and maybe further). It so happens that two rods joined together and shaped into a 'J' is the ideal length required and because the whole thing is threaded, a very low SWR is easily acheivable.

To make the 'J' section, take one of the rods and mark its centre point. Then get a broom handle or something similar and bend the rod around it so you end up with a long thin 'U' shape which will now be a little under 500mm due to the bend. Next, on each arm of the 'U' section, add an M6 nut then two washers and then another nut. These will be used to connect the coaxial cable (they'll take a bit of spinning to get them to the right position!).

The remaining length of rod is joined to one of the 'U' section arms using an M6 threaded hexagonal connector (luckily I had a few in my junk box) which is perfect for the job, but an M6 nut was also added at each end of the connector to tighten it all up. As this isn't a fancy 'enclosed inside a plastice pipe' megabuild it won't be weatherproof, and so is best simply hung from the highest point in your roof space using some string. It is perfectly functional though.

A nice spin-off (pun intended) from using threaded rod is that the dimensions of the antenna can, if required, be fine tuned by screwing threaded connectors onto the ends of the elements and then turning them to effectively increase or decrease their lengths. I found this not to be necessary though, as a good match can be obtained just by experimenting with the connection point of the coax (the outer braid of the coax goes to the shorter element).

The finished antenna will be a bit wobbly, but it'll be fine once hung up there in the roof