FYI some data which I found interesting
My dry earth at end of summer to very wet winter (WWA) causes my
lightning ground system DC (actually about 300Hz AC) resistance to vary
about 40% lower, ie 7+ ohms to 5 ohms. There was also significant
differences from rod to rod re resistance measurements.
How this affects RF properties is of course debatable but I do see a swr
minimum shift of 10KHz or so on my T with 8 elevated radials.
One nearby expert (PhD ULF propagation) told me "acid rain washed out
all the minerals here long ago. We have poor ground." If you really
want to know the parameters, see antennasbyn6lf.com as Rudy describes
techniques for ground RF properties measuring.
It is interesting to know the ground parameters, but what if you don't
like them? Gain and peak angle are affected, but for 1/4wl antennas -
T, L, or full ht aren't significantly differentially affected. For
160m, put up the tallest you can with the most number of ground radials
or 6+ elevated radials. Much more on this on the N6LF web site.
For your flat open terrain place your yagis at heights for the arrival
angles from geographies of interest to your QTH as shown in HFTA.
Ground doesn't matter much.
Grant KZ1W
On 3/23/2020 15:57, Chortek, Robert L. wrote:
Hi Dave,
I’m (just) starting to play with EZNEC and want to know what type of ground I’m
dealing with when I’m running various models.
I live on the second fairway of a.golf course and the way it’s configured I
have literally 1/2 to 1 1/2 miles of grass in certain directions.
It’s watered several times a week during the dry season and during the winter
there is a fair bit of rain.
Don’t know what’s underneath. It’s fertilized twice each year.
Thoughts on quality of the ground for 10-20 meters? 30-40 meters? 80/160?
Thanks!
Bob/AA6VB
Robert L. Chortek
On Mar 23, 2020, at 3:45 PM, Artek Manuals <Manuals@artekmanuals.com> wrote:
[External Email]
On 160M the " skin depth" of ground goes beyond the grass ...so it
depends on more than just your yard but also the type of soil
underneath, how often it is watered , fertilized etc etc.
What are you trying to do that you need to know?
Dave
NR1DX
On 3/23/2020 6:01 PM, Chortek, Robert L. wrote:
A quick question for the collective wisdom on this esteemed reflector:
How would one categorize the quality of ground consisting of grass.
For example, if you live next to a large (many acres) open space made
entirely of well watered grass, would that qualify as �average
ground�, �above average ground� or something else?
Haven�t been able to find the answer anywhere.
Thanks for your input, as always!
73 es DX,
Bob/AA6VB
Robert L. Chortek
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