New GP antenna
It is not quite perfect, but under the circumstances an acceptable compromise. I am a bit handicapped in that I have a flat roof with about 4x12m area - which is unfortunately almost completely covered by a tin roof. So what I did now was putting a relatively short radiator on one side, basically already sticking a bit into the neighbouring house's area.
I had long worried about how to mount this radiator, until BV7GA came up with a very simple solution. The radiator is not stainless spring steel (dreaming...), just regular 4mm steel, 2.5m long. You see it already started to rust, and should there be indeed very strong winds it might even bend. But until then, I will gladly use it.
Above you can see how the feeding is done. So far I am not using an unun, the bottle on that beam is just a choke. I still had a piece of aluminum on my bench, so it was put to good use. The holes were drilled free hand, without measuring, so they are not especially aligned. You may see that I only use seven radials, and that they are not insulated.
The reason is simple: First of all, I did not find other suitable wire, and secondly I have to pull those radials along the tin roof, I can not just put them on the ground. I had hoped originally that I could put this tin roof to good use as either antenna or ground, but I was disappointed both times. Since there is not much space where I could lay the radials, I only used seven so far. There is however one thing the roof does: It shield slots of noise.
I hope that what I deducted from antenna radiation patterns is correct, as I could find only one article somehow dealing with the influence of radials to the radiation pattern. In theory (and if that theory is correct), a radial seems to improve antenna performance opposite to it. That means Europe and also Japan should be somehow OK now. Unfortunately I did not have much chance to confirm this, as I was busy hunting ZL8X (opposite direction) these days - with quite a bit of success I think I can say...
So, time to go hunting now...
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