From G3PLX:
Effectively what Dick is suggesting is having the coil physically at the
bottom where it can be housed and adjusted, but electrically at the top.
This is done by extending two wires down the antenna such that the currents
in these two wires are equal and opposite and they therefore make no
contribution (or degradation) of the antenna performance. If the antenna is
electrically short anyway, it doesn't help to say this is a stub with a
specific electrical length, it's just a coil connected into it's place with
a pair of wires.
If the antenna was hollow, or like a lattice tower, the wire from the top
hat could come down to the bottom inside the structure, so long as it didn't
arc across!
73
Peter
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