Hi Mike, I would have thought that the elevated inductor would have swamped
the aerial inductance. Perhaps the different connection where the currents
in the two outer wires are, in part, opposing the current in the inner wire,
has reduced the effective capacity of the aerial top to ground. I found with
the measurements Finbar did with the spiral aerials that the model suggested
that there were two components to the capacity, that from the portion below
the coil does not (of course) appear across the coil. I have not tried
measuring inverted Ls yet but intend to do a series of measurements latter
when my poles are refurbished. I was intending to look at parallel top
wires, I will now add the configuration you describe as well.

Cheers de Alan G3NYK
[email protected]
http://www.alan.melia.btinternet.co.uk/spiraltop.htm