Hi Ken!
It all depends on the antenna your are going to feed with this loading
coil. My system has a capacitive load of abt. 600pf and so the coil is
abt. 2,3mH. This is realized on a flower pot with about 40cm diameter,
80 turns of insulated wire. The height of the pot is only 30cm.
If you have a smaller capacitive load, you'll need more inductance and
thus increasing the diameter of the coil-body.
If you count 6pf per meter for every vertical part of your antenna and
5pf/m for every horizontal part, you can estimate the capacitive load
very well. For calculation of L and C for a given frequency or for
dimensioning air-coils (Luftspulen), I can recommend the
"Mini-Ringkernrechner"...
http://www.dl5swb.de/html/mini_ringkern-rechner.htm
I don't remember if there's an option for the language on installation
but even if it's only in German, it easy to operate.
73
OE3GHB
Gerhard
Am Donnerstag, den 11.11.2010, 20:28 +0000 schrieb Ken:
> Hello Everyone.
> I went into a branch of Wilkinsons (Watford), today, and saw some
> straight sided cylindrical dust bins about 0.5m diameter, useful for
> large coils?
>
> 73
> Ken
> M0KHW IO91TV
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