SOTA Page
07/05/02
When I started using 2m for activating SOTA summits I found getting contacts difficult using just the short flexible whip “Rubber Duck” antenna. So I was on the lookout for a simple gain antenna suitable for portable use.
I used a design based on an article in the ARRL handbook 1998/9. I use a plummers overflow pipe which comes in 21.5mm X 2m from a local DIY store for the boom.
For the elements I used 3, 6mm X 1m hollow aluminium rods also from the same store.
Reflector should be 40" you can add a stub of aluminium rod to make this
length up if you wish, I just ignored it, and left it at the 1m length as it came.
Connect coax directly to end of driven elements. I used a small bolt through
the end and attached short insulated wires to the bolt, at the other ends I attached spade connectors to enable quick and easy connection to coax. Keep the wires short, otherwise this could affect the SWR, banana plugs fitted at the ends could also be used as these fitted the aluminium rod perfectly
18.2" from the reflector I attached a "omega" shaped plastic pipe holder designed for this pipe to allow a fishing rod (G3CWI's ideal) or pole to go through this holder to support the yagi.
Through my fishing rod it fits conveniently 3/4 the way up just below the apex of my dipole.
I use vertical polarisation, as most contacts I make are on 2m FM.
But conveniently this allows only one stopper or connection of the elements to hold the element halfway through the boom without the need to fix both sides, I use a cable tack with the nail removed, which happens to be 6mm and snaps onto the element, which I then glue and secure with a piece of electrical tape. For the + side of the driven element I just clip on one and temporarily hold in place with tape again.
The completed yagi weighs only about ˝ pound, the elements can be packed inside the boom which can then fit into a rucksack or be attached to the outside.
Hope this works as well for you as it does for me, please Email for further info if required. Struggling to make the 4 QSO’s will be a thing of the past, but don’t quote me on that hi!!
Roger Dallimore MW0IDX
mw0idx at rgdw.fsnet.co.uk
http://www.oocities.org/mw0idx/SOTA.html
