G3LDO wrote:
Also tried a change in the antenna configuration. Mike, G3XDV, found that
connecting the wires at the far end of his capacity top reduced the
antenna
current. My antenna has always had the ends of the capacity top connected
at
the far end so I tried disconnecting them. I also tried spacing them
further
apart to 2m. The result - it didn't make the slightest difference that I
could measure!
No. Sorry if I was unclear. I have three top wires, 18m long, running
parallel and spaced 0.5m apart. The wires have always been joined at the far
end, and this helps reduce the corona losses. I also had them joined at the
feed end, next to the elevated loading coil at the top of the vertical
section. What I did was to disconnect the join at the feed end, so that the
coil fed just the centre wire. The current then went along this centre wire
to the join at the far end, and returned along the two outer wires. This is
what increased the resonant frequency when I would have expected the extra L
in the top wires to decrease the frequency. I have concluded that the
shorting wire close to the coil was probably having a capacitive effect on
the coil and reducing the overall frequency. Whether the top wires are
electrically in parallel or series seems to make no difference at all.
Mike, G3XDV
http://www.lf.thersgb.net
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