Hi Dimitris,
Am 15.02.2013 01:52, schrieb Dimitrios Tsifakis:
Hi Stefan,
A photo of the coil can be seen here:
http://people.physics.anu.edu.au/~dxt103/500/
That big wire is standard house electrical wire for 240V in VK? Looks
like 4...6 mm^2 :-) Rated at 35A? :-)
Well, i would wind ll the turns without the gaps. That makes it more
compact and the coupling will be better. So the L will be higher and so
you will need less wire and get a higher Q. I would keep the distance to
ground at least the diameter of the bucket. The diameter/length will be
quite good.
A Q of 220 is not bad. You may rise it to 300 with that type of wire i
think.
The operating position is inside a little metal garden shed. I have a
wooden bench and it sits on that. There is maybe 0.5 m of space or
more between the inductor and the shed walls.
OK, that is good. But the wire, who do you bring it outside? Maybe there
is a significant C between the wire and the coil to the walls anyway, in
relation to the antenna C.
Ground losses are estimated to be a bit less than 20 ohm. This varies
a bit with the WX, currently after a bit of rain think it is probably
around 17 or 18 ohm. There is clay under the soil, which I think is
good news when it comes to conductivity :-)
Going from 27 ohm to say (Q=1000) about 20 ohm antenna impedance,
would result in a small but very welcome antenna current increase...
And what about the radiation resistance? Have you already reached the limit?
73, Stefan
73, Dimitris
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