Hans-Joachim Brandt wrote:

Besides just noting the change It would have been interesting, of course, to
find out into what direction the ground resistance has changed. On one of the
last cold days and before the snow had disappeared I checked it with a resistive
bridge to find that the total feed point resistance of my antenna (when tuned to
resonance) had decreased from 100 ohms down to 60 ohms!!!

I do not have a reference at hand to quote a definitive response, but my
recollection of ground parameter data is that frozen ground is "bad
news" for ground wave loss, as is fresh water.  Your measured result is
the other way round.  I will try to find a text book reference on frozen
ground losses versus unfrozen.

By the way, the temperate climate here in Wellington, New Zealand
involves a few frosts in the winter but no frozen ground as such, so I
have not experienced the type of conditions that Hans-Joachim is more
familiar with.

73, Bob ZL2CA