N9ADG wrote:
>How can we correlate "good" and "poor" soil qualities
to the US gov't survey (mentioned in previous postings
to this list)? I envy the "30" and even the "16"
areas, being in a "4".
"Very Good": conductivity = 30 mS/m, dielectric constant = 20.
"Average": conductivity = 5 mS/m, dielectric constant = 14.
"Very Poor": conductivity = 1 mS/m, dielectric constant = 5.
NH6KB wrote:
>Thanks for the information. I don't get NCJ, so could you fill in a
couple of details? Does all of this information assume a full quarter
wavelength vertical above the radial system? And this is for 1.8 MHz?
Modeling data is for a full size 1/4 wl vertical. 40/80/160 are
covered in the article but the data I posted was for 160 only.
>I have very good ground conductivity in my yard. If I had radials 10'
off the ground, my inverted L would then have only a 30' vertical
section instead of 40'. I would like to know if the improvement from
using raised radials would be offset by the reduction in efficiency of
having a shorter vertical portion in my inverted L.
That could only be answered by modeling, but based on
Fig 10 in the second article, I would guess you are better off with
your 40' vertical assuming you already have a decent radial system
(at least 30 radials).
For those of you who are not NCJ subscribers, you might
want to consider it even if you are not a contester. It is now the
only publication I subscribe to besides QST which is "free" since
I'm a lifetime member. Cost is only $20 per year and Carl K9LA
is doing an excellent job of editing it. Check it out here:
http://www.ncjweb.com/
73, Bill W4ZV
http://www.ncjweb.com/
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