Hi Ignacy,
Salt water is very special! In a salt water environment potentially
the entire Fresnel zone -- where as much a 6 dB of gain is obtained
from ground reflection -- is in a highly conductive environment.
Low angle radiation from a vertical with a salt water Fresnel Zone
is much better than from an inland vertical.
In a inland location only a very small fraction of the Fresnel Zone is
covered by conductive radials.
73
Frank
W3LPL
----- Original Message -----
From: "Ignacy Misztal" <no9e@arrl.net>
To: topband@contesting.com
Sent: Tuesday, November 6, 2018 8:45:28 PM
Subject: Topband: Accuracy of modeling of 160m verticals
A number of articles analyzed 160m verticals by simulation. Once the height
was lambda/8 and the number of radials >= 16 (buried) or >=4 (elevated),
the difference in gain was at most a few db.
I operated the 2017 Stew contest from a northern beach of St George Island,
FL. The antenna was inv L about 55 ft vertical and 90 ft horizontal,. with
one 70ft radial elevated 5 ft.
The performance was astounding. EU was heard one hr before the sunset, in
bright sun..During the contest, EU were only slightly weaker than the US. A
special point was easily working a DL with 100W while a well known
contester using high power 100 miles inland could not work it.
So it seemed that the salt-water enhancement was like 15 db, not a few. I
wonder whether simulations are inaccurate with respect to radials/soil
type or is salt water special?
Ignacy, NO9E
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