Monday 7 January 2008

Getting my wood up

I now have everything i need to put the two VHF beams up (other than a rotator), pole, brackets, coax, connectors, and tape. BUt the weather won't let me! when the weather is fine, theres no one about to assist, and this isnt really a job i can do on my own.

I built today a wooden mast from 2x3 tanilized timber and galvanized bolts. This is just over 30ft tall, and will carry one end of my doublet via a pully block. It is semi-free standing. It will be fixed to a laylandii tree trunk, and have the bottom sunk into a brick lined hole. There will be a few guy ropes, but the purpose of these is to act as fall arrestors should it fall for any reason, and to swing the beast safely into the hedge. Only one guy will be for another purpose - to take the force from the antenna. I cant put this up yet, because i dont have suitable fixings to attach it to the tree yet, and besides its dark now.

Ive also constructed an 'ugly' 1:1 choke balun, from 4" PVC soil pipe, and 30ft of RG-213 i had laying about. I had to buy the pipe, but wanted some anyway for making bait stations. Just as well, 'cos its bloody expensive! About 8-9ft of coax is provided as a tail with a PL-259 to connect to the tuner, and about a 6" tail the other end for a connection box to attach the balanced line up to the doublet. The 21 turns of coax are held in place by a number of cable ties fixed through holes drilled in the pipe. Im hoping when finished this balun will prove more effective and less prone to saturation than the 4:1 colins coax balun im currently using, which is made from RG-58. I just need to find a suitable connection box now.

The doublet is performing quite badly. I think its due to the long run of coax currently in use, and the balun, which is at the moment laid on the garage roof and exposed to the rain. I have noticed rain causes tremendous shifts in tuning settings, often to an entirely diferent inductor setting, and sometimes it just won't tune at all! That said, despite the trouble, and by waiting for optimum conditions, i worked PZ5YV, the DXpedition to Suriname! at least i think i did, strange how you get a bit paranoid about these things! and the online logbook isnt working.