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Old August 8th 03, 02:30 AM
Yuri Blanarovich
 
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The vertically polarized noise in my neighborhood is the real killer
of verticals.
--
73, Cecil http://www.qsl.net/w5dxp




Hmmm,
all the noisey appliances in the neighborhood are vertically polarized?
Trolling for another argument "threat" :-?

Yuri
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Old August 8th 03, 03:12 AM
W5DXP
 
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Yuri Blanarovich wrote:
The vertically polarized noise in my neighborhood is the real killer
of verticals.


all the noisey appliances in the neighborhood are vertically polarized?


A very large power transformer mounted on a pole at the edge of my
property has a 35 foot ground wire running down the pole about 100 ft
from my vertical. I suspect that is the source of the vertically
polarized noise.
--
73, Cecil http://www.qsl.net/w5dxp



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Old August 8th 03, 04:07 AM
Yuri Blanarovich
 
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all the noisey appliances in the neighborhood are vertically polarized?


A very large power transformer mounted on a pole at the edge of my
property has a 35 foot ground wire running down the pole about 100 ft
from my vertical. I suspect that is the source of the vertically
polarized noise.
--
73, Cecil http://www.qsl.net/w5dxp



and no horizontal wires attached to it?
Is transformer producing noise? Or bad connections, arcing?
Mabee vertical antenna due to its pattern is "seeing" more noise than your
ladder fed wunderdipole?

I think there is a major misconception that verticals are more sensitive to
noise because the noise is "vertically polarized". Man made, appliance or
otherwise produced noise is "all kinds" polarized. It is the antenna's location
and radiation pattern that determines the amount of noise or S/N pick up.

Yuri
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Old August 8th 03, 06:29 AM
Dave Platt
 
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In article ,
Yuri Blanarovich wrote:

I think there is a major misconception that verticals are more sensitive to
noise because the noise is "vertically polarized". Man made, appliance or
otherwise produced noise is "all kinds" polarized. It is the antenna's location
and radiation pattern that determines the amount of noise or S/N pick up.


Well... yes and no (I think).

As I understand it, ground-wave / surface-wave propagation occurs for
vertically-polarized signals (or signal components), but not for
horizontally-polarized signals (or components). Even if manmade noise
is polarized in all planes with equal (or randomly distributed)
polarization senses, only the vertically polarized portion of it will
travel via groundwave propagation.

So, I suspect that the noise-proneness of vertical HF antennas
compared to horizontal dipoles, probably results from a "double
whammy". The horizontal antennas aren't exposed to anywhere near as
much energy propagating via groundwave (because horizontally-polarized
noise doesn't travel well in that mode), and they aren't as sensitive
to it because they often have fairly high radiation angles with a
substantial null towards the horizon.

The vertical antennas are hit with more noise energy, and due to their
low radiation angle they're pretty good at picking it up.

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
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Old August 8th 03, 07:25 AM
Mark Keith
 
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Roy Lewallen wrote in message ...
Mark Keith wrote:
. . .
Also, I suspect excess loss if the noise and signals drop compared to
any other antenna. If the coax is not bad, old or waterlogged, or thin
stuff like rg-58, then I'd suspect excess loss in the autotuner. . . .


Out of curiosity, just how much loss do you think "thin stuff like
RG-58", say 50 feet of it, has on 20 meters?

Roy Lewallen, W7EL


Normally it shouldn't be too much. But if the "thin" stuff is old, or
has been damaged , it might be more than usual. MK


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Old August 8th 03, 07:46 AM
Mark Keith
 
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(Jeffdeham) wrote in message . com...
W5DXP wrote in message ...
Kristinn Andersen wrote:
Any comments, anyone, before I remove the vertical and turn to another
design?


I spent considerable time and effort erecting a 33ft vertical 40m
antenna with 8 elevated radials at 20ft. Average signal strengths were
about 2 S-units below a dipole and the noise level was about 2 S-units
higher than the dipole. At my QTH, it was a dog.


I had exactly the opposite results. It was 2-3 S units better at low
angles of radiation compared to my low dipole. I've heard other
experiences like this too. I just wonder if there some part of antenna
theory that's missing that could explain why that happens. Murphy's
law, blind luck, who knows. 8-)

73!

Jeff


It's simple. Cecil did not use enough radials for the low height he
mounted the vertical. Also, he didn't use it to work much long haul or
dx, which is what the vertical is best for. His antenna was just a bit
higher than an 1/8 wave. For an antenna that high to equal a GP at 1/2
wave with 4 radials, he really needed nearly 40-50-60 radials. A 1/2
wave high GP with 4 radials = a 1/4 wave high GP with 8-10 radials = a
1/8 wave high GP with 50-60 radials = a ground mount with 120 radials.
They all have the same appx ground loss. Now look at Cecils GP at a
bit over 1/8 wave and only 8 radials. Thats not much better than a
ground mount with 16-20 radials. No one will ever confuse a vertical
with 120 radials against one with appx 16-20 in the real world. I ran
a 40m GP at 36 ft, which is a bit over a 1/4 wave up. I used only 4
radials, but my antenna was appx equal to a ground mount with about 60
radials. My ground cdx are better than his also, so if anything he
should need more radials than I did. To me, his results are about as
to be expected. Heck, on 40m at night, my mobile vertical antenna will
outdo my home dipole at 42 ft to anyone at least 1000 miles away. I've
tested it many times. And my mobile antenna was a peanut whistle
compared to the full size GP I ran here at the house. To VK, Japan,
EU, etc, my GP would always be 3-4 S units better than my dipole at 36
ft. Heck, I'd give Tokyo a 20 db over 9 window rattling when I ran
that GP and a full KW. My dipole would be lucky to be S 8-9 with the
same power. MK
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Old August 8th 03, 08:35 AM
Roy Lewallen
 
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Well, 50 feet of RG-58 has about 3/4 dB loss at 14 MHz. And when it's
old. . . I've got RG-58 that's well over 20 years old, and can't measure
the difference in loss between it and new cable. If it's damaged, it
might create an impedance bump, which you might or might not notice. But
that's true of larger diameter cable, too.

I'm bemused to find that today's hams have somehow gotten convinced they
all need BIG cable for a BIG signal. Maybe they've been listening to the
same ads that sell people on monster audio cables and SUVs. But I sure
hate to see this misleading concept being passed along to newcomers.
They'll fall for the ads soon enough without help.

Roy Lewallen, W7EL

Mark Keith wrote:
Roy Lewallen wrote in message ...

Mark Keith wrote:

. . .
Also, I suspect excess loss if the noise and signals drop compared to
any other antenna. If the coax is not bad, old or waterlogged, or thin
stuff like rg-58, then I'd suspect excess loss in the autotuner. . . .


Out of curiosity, just how much loss do you think "thin stuff like
RG-58", say 50 feet of it, has on 20 meters?

Roy Lewallen, W7EL



Normally it shouldn't be too much. But if the "thin" stuff is old, or
has been damaged , it might be more than usual. MK


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Old August 8th 03, 09:29 AM
W5DXP
 
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Yuri Blanarovich wrote:
I think there is a major misconception that verticals are more sensitive to
noise because the noise is "vertically polarized". Man made, appliance or
otherwise produced noise is "all kinds" polarized. It is the antenna's location
and radiation pattern that determines the amount of noise or S/N pick up.


I'm just reporting what conditions exist at my QTH. There is approximately
two S-units higher noise on the vertical than on the horizontal. After weeks
of A/B comparisons, there was never a time or signal where the vertical appreciably
beat the horizontal. There were a few times when they were nearly equal. Two extra
S-units of noise is hard to overcome. I really wish the outcome had been different.
--
73, Cecil http://www.qsl.net/w5dxp



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Old August 8th 03, 09:34 AM
W5DXP
 
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Roy Lewallen wrote:
One thing to keep in mind is that vertically polarized waves can
propagate by ground wave, while horizontally polarized waves can't.


There are locations around my home town where the power line noise
completely blanks out WTAW, a 10KW AM station 30 miles away.
--
73, Cecil http://www.qsl.net/w5dxp



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Old August 8th 03, 09:46 AM
W5DXP
 
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Mark Keith wrote:
It's simple. Cecil did not use enough radials for the low height he
mounted the vertical.


I used *twice as much wire* for radials in the vertical as I used for
the entire horizontal antenna. :-) In addition, the top of the vertical
was 15 feet higher than the horizontal and was a lightning rod. In
addition, the RG-213 cost three times as much as ladder-line. Anyone
need a 33 ft aluminum tubing vertical? Come haul it away.
--
73, Cecil http://www.qsl.net/w5dxp



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