Hello Bill,
First. Is 7mm the actual wire diam or the wire plus insulation?
7mm is de actual diameter, there is no extra isolation around the whole
bunch of wires.
>What distance should I keep to the ground ?
I like 6 feet as the best compromise. The ground loss will amount to about
1/2 of your total loss loss with a loop this size and conductor Rac this
low. I'll give you a number later, based on my data.
OK, I'll keep the lower part 2m - 6ft8 from the ground for practical
reasons (I'm 1m90 - 6ft4)
>What distance should I keep to the greenery (birch trees)
The trees will have almost no effect. I run my conductor (now a 1/2" Cu
pipe, in full contact with the trees (see my loop website at
http://www.ThePittsfieldInn.com/Bill/ for a picture of this), but it's a
good idea to have some spacing at the lower portions of the loop where the
voltage to ground is the highest. Also, you will have to protect the Litz
wire from abrasion from the trees. That's a valuable piece of cable!
That sounds great, 'close contact' to the trees would allow me to increase
the loop area from 300m^2 to 350m^2.
>How to match the antenna ? As it is an experimental setup I would tend to
>keep the resonance tuning (= series capacitor) and impedance matching (=
>transformer) separated.
DO NOT separate these components! This a very common mistake. The
transformer and capacitor bank must be next to the loop feed point or the
losses will kill you.
OK. I didn't mean to put them at different places, just to make resonance
tuning and impedance matching independent of each other.
What I had in mind was something like fig.2b in your loop article
(http://www.thepittsfieldinn.com/Bill/Loop1.htm)
73, Rik ON7YD
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