Tuesday 14 August 2007

antenna height

Now, this is something i freely admit - ladders terrify me. Its not the height, its the ladders. I love being up high, i can stand on the edge of a roof and look down without a care. But actually going up ladders i hate. Yet its unavoidable if i want decent antennas. So, ive bought a new ladder, practically the biggest they had, and certainly more than enough to reach to and beyond the apex of the roof to work on the turnstyle antenna and the met instruments. Ive also bought a stay bracket that gives the ladder between 1-2ft clearance from the wall, so i'll have space to work. There was no point getting a smaller set of ladders that would 'just' reach. Even if i dont use these fully extended, that will just add to the stability and my safety.

So, next job then is to repair the vhf turnstyle antenna for the weather satellites. This needs a whole new coax run. I can check and test the anemometer in situ as well and recable that if required. I may rig a rooftop receive only random wire as well for the FRG-100 to replace the wire that goes down to the tree.

I also need to improve the support for the doublet. This im going to do by building a 25ft wooden mast. Built from tanalized 2x4, it should do a good job and be aethetically pleasing (or at least not too ugly). The difficult part, is that for it to be freestanding will require a foundation some 6ft deep. So i need to invest in, or borrow, some post hole diggers. I may replace the 1" allow tube mast at the roof apex with something a little stronger as well.

Thursday 2 August 2007

Balun

yesterday, i spent some 5hours, on and off, through the afternoon and evening, chasing DX. Well, chasing anything! I could hear so much - colombia, madiera, egypt, thailand, USA, isreal, couldnt work anyone! it seemed all my power was vanishing before it hit the ether. Only at midnight did i make my one and only QSO, into Nova Scotia!

Today i changed from the ATUs internal 4:1 toroidal balun, to the Collins coaxial i have built -


now, whether the conditions are better, which i dont think is the case, or whether the coax balun really is so much better, i cant say yet. What i do know is this morning ive worked Belarus, Sweden, and now Morocco, on the first call each (well, ok, CN8ZG was second call), all with this balun in line. The ATU is letting me tune up at maximum capacitance settings ( zeros on the dial) just as the manual says i should, and ive even been able to get tuned up on 17m and 15m. Shame both bands appear to be closed at the moment. So it certainly seems to be doing well. My first couple of QSOs using it quickly faded away, leaving me thinking the balun had saturated and lost all signal, but listening to comments from others on 20m revealed that this morning the band was suffering badly with QSB anyway.

I still think some feeder adjustment is needed, but i now have the feeling im on the way to a good all round antenna.

I also worked GB4IPY on 20m, but as that station is in Wakefield, about half an hours drive away, i could have worked him on the dummy load! I think the 100W i was using was a bit much, that said i didnt bother to tune up!