Hi all,
I've not been following all bulletins on loops, but a comment on frequency
range should be made for any "inductance formula". Because of "long"
wavelengths at LF, most amateur loops are "small" in terms of wavelengths,
so a "constant current" approximation can usually be made. When the loop
diameter is a significant part of a wavelength, the current distribution
starts to have "standing waves" and the radiation characteristics (impedance
and pattern) are quite different to the electrically small loop.
For a multi-turn loop, inter-turn capacitance also modifies the "inductance"
at higher frequencies, so there comes a time when a single turn loop
(possibly with parallel wires) is the better performer.
I'm not sure where the regions are that low frequency inductance formulae
need correction, and similarly for multi-turns.
73, Bob ZL2CA
|
