Hi Darrell,
In a message dated 96-10-01 03:15:40 EDT, you write:
> Your comments are refreshing as they are accurate and clearly state the
case
>that absolute statements are not always true no matter how many names are
>quoted. Keep up the inputs. Don't let the doubting Tom's of the world talk
>you out of it. 73
Before we get carried away with little bits of funny humor let me explain why
I'm a "doubting Tom". I reseach things before I get caught up in a "new
frenzy". When the elvated radial thing came out, and everyone else was
expeimening in the warm house in front of a CRT, I went outside and put up a
test antenna in a clear area and made FS measurements at one mile as I
changed the ground system. I went to New Jersey and made the same change and
made dozens of FS readings at a BC station.
Much of the stuff accepted as fact or published in articles has no technical
basis, and instead is founded on rumor and folklore. People trying to learn
don't deserve that type of garbage.
Some is based on models that have not been confirmed by FS measurements and
gut feelings.
I see no harm in mixing a little reality and a few documented facts in with
the conjecture, gut feelings, and magic of antennas.
The Brown, Lewis and Epsteins report on ground systems was the most
comprehensive study ever done in the world to date, and three of RCA's top
engineers were involved.
With a nearly perfect ground system (more than 60 radials 1/4 wl long) they
found a ground screen made absolutely no difference at all.
>P.S. Yes, a ground screen can really help. We measured an increase in
>antenna current which equates to lower ground loss. When it comes to
>elevated radials the fewer and higher the better but not less than 2.
With poor grounds of less than 15 wires (systems with poor efficiency with
radials along) they found the ground screen made an improvement. The systems
became less poor (but not good).
I can understand your disagreement, because your conclusion agrees with L,B,
and E. With the poor ground like two or more elevated radials, a ground
screen would help a lot. Ground screens help poor grounds, they just don't
help good ones.
I'm glad your results agree with the L.B and E study. If you have a poor
ground, the screen will certainly help. Anything is better than nothing.
73 Tom
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