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#1
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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. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 80,000 Newsgroups - 16 Different Servers! =----- |
#2
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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 |
#3
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For horizontal antennas -- the radiation angle becomes lower as the height
of the antenna increases and vice versa (with caveats) A layman's explanation at URL: http://www.signalengineering.com/ult...radiation.html Excuse the CB reference -- but it has some nice pictorials. Those mathematically inclined can model antennas at URL: http://www.eznec.com/ ================================================== ==== "Jeffdeham" wrote in message om... 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 |
#4
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Jeffdeham wrote:
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-) The vertically polarized noise in my neighborhood is the real killer of verticals. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 80,000 Newsgroups - 16 Different Servers! =----- |
#5
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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 |
#6
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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 -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 80,000 Newsgroups - 16 Different Servers! =----- |
#7
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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 |
#8
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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 I do _not_ wish to receive unsolicited commercial email, and I will boycott any company which has the gall to send me such ads! |
#9
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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 -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 80,000 Newsgroups - 16 Different Servers! =----- |