19 Mar 2011
At first sight the idea of a 10m x 10m wire loop as a TX antenna at 8.97kHz VLF sounds a non-starter as a way of radiating any useful power. Having tossed the idea around with others though it appears that, although very inefficient, it would not be that much worse than a smallish Marconi vertical because these antennas need very large (and lossy) loading coils, height and good grounds to be effective. With 100W to such a small loop around 0.45uW could be radiated. Already G3XIZ has spanned 218km with just 2uW to his vertical, so for small gardens the VLF TX loop is worth a look.