niedziela, 27 marca 2011

18 meters fiberglass mast from Spiderbeam

Some analysis of my IARU HF Championship results show that my weak side are the lowbands (in this case 3.5 and 1.8MHz). Last year I tried to use a dipole with traps for these two bands (all the dipole is 80 meters long) but as you may suspect it is quite difficult to find a location where such dipole could be used. I guess that for such antenna I should have the height more than 3..5 meters above the ground... Last time I could use only my aluminium masts so the height was between 8..12 meters (dipole ends) - for 80..160 meters seems to be not enough.

I decided to built some GP antenna for 80 meters (and use it on 160/40m as well). I bought a 18 meters fiberglass mast from, some wire and ropes.

Some evening equiped with all necessary tools, ropes, clamps, wires etc etc I visited my favourite "test hb9ega area" where I try all new radio ideas...

Initially I used simple configuration with just around 20m of wire along the mast and a few 20..40 meters radials around. It was loaded directly from coaxial cable. I did some tests but probably not enough to decide if it works fine or not...

I had to recalculate the lengths of guy ropes ...

As usual the requirement was that all the action related to erecting the mast must be able to be done by one person. With this mast it is no problem. Just need to create one "virtual" person who holds the base of the mast in one place:

Finally mast achieved vertical position and looked really impressive (18 meters!!).

Unfortunately that was a little bit to late and dark to make some more sophisticated tests.

Lets see how it works in future (especially in contest :))

Brak komentarzy: