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#1
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![]() "JIMMIE" wrote in message oups.com... While operating on 10M I have observed that a halfwave vertical dipole will communicate to different areas than a 1.25wl vertical monopole an example would be that during a band opening the 1/2 wl antenna may be working predominantly into New York while the 1.25 wl antenna is working best in California or was it vice versa. This has proven useful for me, instead of fighting a pile-up and can just talk somewhere else. The two verticals may soon be replaced with a tri- bander and I was wondering if I could get this same type of effect by tilting the antenna vertically(no change in polarity) with a remote controlled device. I think it would be pretty cool to hear different areas of the country pop in and out as the elevation of the antenna is changed. It would work, theoretically, for a small change but I doubt you'd ever notice the effect. You need a very directional (many elements) antenna to see a big difference in the amount of signal in the elevation plane. High gain UHF TV antennas do have tilters, but it's to match the angle of arrival of the signal, which may be coming out of a duct or reflected off a nearby ridge. See a sample at http://www.atechfabrication.com/prod...omy_tilter.htm Most tribanders are three elements and have a 3dB beamwidth of about 60 degreees in the azimuth (plan view) plane -- worse in the elevation plane. Further complication: The ground affects the shape of the elevation pattern, maybe more than any tilt you could apply. You might better fine-tune the angle of arrival by cranking a tower section up and down. "Sal" |
#2
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![]() "Sal M. Onella" wrote in message ... "JIMMIE" wrote in message oups.com... While operating on 10M I have observed that a halfwave vertical dipole will communicate to different areas than a 1.25wl vertical monopole an example would be that during a band opening the 1/2 wl antenna may be working predominantly into New York while the 1.25 wl antenna is working best in California or was it vice versa. This has proven useful for me, instead of fighting a pile-up and can just talk somewhere else. The two verticals may soon be replaced with a tri- bander and I was wondering if I could get this same type of effect by tilting the antenna vertically(no change in polarity) with a remote controlled device. I think it would be pretty cool to hear different areas of the country pop in and out as the elevation of the antenna is changed. It would work, theoretically, for a small change but I doubt you'd ever notice the effect. You need a very directional (many elements) antenna to see a big difference in the amount of signal in the elevation plane. High gain UHF TV antennas do have tilters, but it's to match the angle of arrival of the signal, which may be coming out of a duct or reflected off a nearby ridge. See a sample at http://www.atechfabrication.com/prod...omy_tilter.htm Most tribanders are three elements and have a 3dB beamwidth of about 60 degreees in the azimuth (plan view) plane -- worse in the elevation plane. Further complication: The ground affects the shape of the elevation pattern, maybe more than any tilt you could apply. You might better fine-tune the angle of arrival by cranking a tower section up and down. "Sal" Thats really what I thought to, I dont think it would be practical to implament with a yagi. I have too also admit the extreme variations I reported while using the verticals is pretty rare and I made them sound more common than they reallly are. Jimmie |
#3
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![]() "Jimmie D" wrote While operating on 10M I have observed that a halfwave vertical dipole will communicate to different areas than a 1.25wl vertical monopole an example would be that during a band opening the 1/2 wl antenna may be working predominantly into New York while the 1.25 wl antenna is working best in California or was it vice versa. This has proven useful for me, instead of fighting a pile-up and can just talk somewhere else. The two verticals may soon be replaced with a tri- bander and I was wondering if I could get this same type of effect by tilting the antenna vertically(no change in polarity) with a remote controlled device. I think it would be pretty cool to hear different areas of the country pop in and out as the elevation of the antenna is changed. I don't know how you missed it, but there have been several threads here recently about TOA, tilting antenna elements, purity of polarity, ect...A google search on Art Unwin will provide more than you'll ever want to know, especially about mental health and junk science. The demo version of EZNEC should also provide you with plenty of useful answers, and will sink enough of your time to keep you off the streets and out of the bars!Several programs will allow you to model effects of changing antenna heights ( only one of a multitude of variables) on the resulting signal path. Keep us here on RRAA posted on your results, and gud luck in the contests! Mike W5CHR |
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