[TowerTalk] ground and conductivity

[Jim Lux]

At 12:55 PM 2/28/2005, Tom Rauch wrote:
> > I believe that fresh water has very poor conductivity.
>Salt water has very
> > good conductivity.
> >
> > Les W2LK
>
>
>That's correct, but lakes have contaminants that increase
>conductivity significantly over pure fresh water.
>
>For example the Great Lakes' conductivity is in the range of
>poor to fair soil, or about 8mS/m.  Sea water is 5000 mS/m.

A Canadian gov't website claims that the conductivity of the Great Lakes 
water feeding into the St. Lawrence is about 300 uS/cm (=30 mS/m).  I grant 
that this is at the downstream end of all the cities on all the lakes. 
Milwaukee's water department reports that their intake water (from Lake 
Michigan?) is around 200 uS/cm (20 mS/m)



>Just plain old dirt ranges from less than 1mS/m up to 30 or
>more.
>
>Not that it matters all that much for skywave.

The high dielectric constant (epsilon) is probably much more important.