[Lowfer] Frozen trees ??

[JD]

>>> Which leads me to ask the question at what distance are trees no longer 
>>> detrimental to the radiated signal of a short LF vertical antenna?

Depends on how much loss one considers detrimental.  For NO interaction, the 
spacing would need to be multiple wavelengths.  For theoretically acceptable 
interaction, it would be 1/(2pi*wavelength).  But as a practical matter, a 
good rule of thumb would be the sum of the height of the antenna plus the 
height of the tallest tree.  If you wanted to add another 5-10% for good 
measure, be my guest.

How do I arrive at that conclusion?  The bulk of the reactive energy is 
going to be within a radius amounting to the height of the antenna plus a 
few percent for fringing effects.  That'd be the absolute minimum, IMO.  If 
you want to consider the trees as super-lossy antennas themselves, then 
adding their height to the desired minimum separation also makes sense 
(plus, physically speaking, their roots can spread out that far, adding to 
the interaction with your ground system).

On the farm, my antenna is only about 150 feet from the 70-foot trees along 
the west fence row because I don't want to interfere with crop production 
any more than necessary; but still, the total ground system loss is less 
than 10 ohms and doesn't vary much with seasons any more.  Fom those facts, 
I conclude I have very little tree interaction.

John