Today saw another 200m of wire added to the long wire antenna.
Its impedance dips to a minimum of 70 ohms at about 170kHz
corresponding to a free-space quarter wavelength of 440m which
is somewhat less than my estimated total length of wire.
100uH in series brings it into tune at about 135kHz and presents
an impedance of 50 ohms and the tuning is quite broad, I don't
think I need a variable inductance.
Can anyone advise a good frequency on which to test which
won't get in anyone's way? I expect to be using symbols
one second or longer.