The experience here during the stations contest days of the 90's was with a
high inverted V at 160-180' (added 20' to the tower after a lightning hit)
along with a pair of 1/4 wave verticals with 32 raised radials of somewhat
random lengths in the 100-130' range running thru the woods. Those used
simple CATV RG-11 coax phasing lines and relays to switch endfire directions
or a broadside figure 8. Im still a big believer in KISS and not throwing
money away at commercial solutions that offer little or no added benefit.
Single Op contest results were that the 160 part of the score was at the top
of the pack or close to it and was also right up there with the MM stations.
My conclusion which also included pileup busting DX chasing was that the
only improvement left to be gained was increasing the outpower from 1200W
which was already around 3dB down from many and a lot more from several
others. I still run the same 1200W amp.
Im 20-30 miles from salt water, on the top of a granite hill with very
little soil but a killer take off angle. N6BV/1, who lived the next town
over and Ive known since he started at National Radio fresh out of college,
modeled it for a HFTA release which was part of the K6STI AO or YO package.
Ive also mentioned the "awesome" performance of an inverted V with the apex
at 50' and ends at 3' when I first moved here. It was put up in a hurry to
work one of the Antartic island DXpeditions and cracked one of the biggest
pileps Ive ever heard on one call. Later at Dayton the op said I was at
least 10dB above everyone and the only call he could copy. Bob Brown had
used that to add to his ducting theories.
My own conclusions are that a low loss vertical and a horizontal of some
modest XX height are needed if you want to be highly competitive. All this
talk about what happens at 0-5 degrees or wherever is good to toss around
but I doubt it has much to do about what really works for those of us not
right at the salt water.
Carl
KM1H
----- Original Message -----
From: "Mike Armstrong" <armstrmj@aol.com>
To: "Tom W8JI" <w8ji@w8ji.com>
Cc: "Mike Waters" <mikewate@gmail.com>; "topband" <topband@contesting.com>
Sent: Wednesday, October 24, 2012 11:08 PM
Subject: Re: Topband: Monopole Elev Pattern w.r.t. Earth Conductivity
Dang Tom..... I just sent out a more wordy version of what you just said.
This is getting strange. Not sure why it hasn't been disseminated yet (my
email), but I swear I sent it just moments before your email hit my
system.
You just added some fuel to my fire. Short version: I, with my rather
inexperienced eye (160 experience, that is) is seeing a pattern that seems
to indicate what we would call low radiation angles aren't really optimum
for long range 160 communications. The other email goes into a little
more detail in why I am thinking this way. Morning enhancement,
especially with high angle radiators (like mine) where I am working Japan
and Chile on a radiator that can very truthfully be called an NVIS
antenna. On higher frequencies, a scaled version of my antenna wouldn't
radiate a signal out of the southwest region, much less thousands of miles
distant.
Just a thought! Again, my other email expounds a little more, but this
was the conclusion in a nutshell. Maybe "low horizontal" antennas really
ARE better on 160 than they should be..... Given our experience with low
antennas on the higher bands, it seems counter-intuitive..... But there it
is.
Mike AB7ZU
Kuhi no ka lima, hele no ka maka
On Oct 24, 2012, at 17:12, "Tom W8JI" <w8ji@w8ji.com> wrote:
If we knew those, then we could calculate the location and distance of
the
signal hops. That might give us some insight as to why some people have
found a taller monopole to be worse than a shorter one at a given
distance.
Back in the 70's or 80's there was speculation a low angle was lossy from
grazing along, based on others having poor experiences with taller
verticals. The top of my tall tower had some antennas and side arms which
top loaded it a bit, but not much. Certainly the wave refracts gradually
at a minimum, and so I think distance would not tell anyone much. There
have been a host of theories since the 1960's, even some from Stew the
real W1BB. :-)
I don't know what happens when it gets up in the soup, although people
like K9LA should be pretty well versed on it. I only know things behave
differently all the time, and what antenna generally works most of the
time.
For example, at sunrise most of the time almost anything reasonably
efficient works about the same here. It's more a matter of ERP at any
not-too-low angle and any polarization.
73 Tom
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