In article tonline, Roy
Lewallen wrote:

It sounds like the model of the pickup was inadequate -- it's at least
as important as the vertical. How did you model it?

Roy Lewallen, W7EL

Hello, and that could well be it. After using NEC-4 to model USN HF
antennas in their intended operating environment one finds that the local
environment often requires beaucoup more wire segments (I never completely
trusted patches) to model than the antenna itself. If conductive objects
in close proximity can be excited by antenna currents then they are part
of the antenna. A USN example would be the 2-6 MHz twin fan-type antenna
that relies heavily on induced currents in the ship's stack for its
feedpoint impedance and radiation characteristics. Sincerely, and 73s
from N4GGO,

John Wood (Code 5550) e-mail:
Naval Research Laboratory
4555 Overlook Avenue, SW
Washington, DC 20375-5337