Bob wrote:

> Wonder what effects soil conductivity changes has on the
> propagation at these VLF freqs??

I have no information.   You would expect ground resistance
to rise, but would that make noticeable difference to
propagation if it is only a freezing of a shallow surface
layer?

I had to go to a narrower bandwidth to produce phase and
amplitude plots for last night's test

 http://abelian.org/vlf/tmp/29499_140308a.gif

Signal is down by some 5dB compared with some recent
tests.

Nothing detected this afternoon.

Propagation seems normal, noise floor normal.

Maybe the cold and frozen ground is affecting the tx
efficiency, some lower Q of the loading coil - antenna -
ground loop, or a reduction of effective height.

Will be interesting to see what happens after the thaw.

--
Paul Nicholson
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