Jim and LF readers,
Thanks for further analysis and plotting of results. My LF antenna is not
very big, and has shrunk in capacitance since I did those impedance runs. I
decided to "borrow" the top of a wooden pole on the street frontage to
support the outer limit of my top loading, but some time later I received a
"Dear John" letter from the telecommunications company, and in short I
removed my wires ....
I do have quite a good earth mat of buried copper wire, with a near radial
layout with respect to the feedpoint of the vertical, with 14 or 15 wires.
I installed the earth system in the 1980's when I had interests in working
DX on 80 and 160 metres, and I did get 59 SSB exchanges with Europe. I have
since added driven pipes at selected outer ends of radial wires to assist LF
currents to migrate beyond the boundary of my suburban property. So I
attribute my "lower loss" to the earth system rather than the wires above
ground. However, my ground is still in "power factor territory" compared to
that assumed in broadcast antenna text books. My top loaded vertical
currently has an 8 metre upwire, but I intend to add 5 metres or so with a
fibreglass windsurfer mast.
73, Bob ZL2CA