19 Mar 2011

Loop TX antennas at VLF

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.

1 comment:

Bert, PA1B said...

Hello Roger,

If you have the room to make a loop, I should just try it, to get the experience.
I had good results with an indoor loop for 7 MHz with a length of 7 mtrs, with a smaller coupler loop.

73, Bert PA1B