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#1
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Effects of TOA
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. Jimmie |
#2
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Effects of TOA
"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" |
#3
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Effects of TOA
"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 |
#4
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Effects of TOA
"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 |
#5
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Effects of TOA
On 13 Apr 2007 16:41:25 -0700, "JIMMIE"
wrote: I have observed that a halfwave vertical dipole will communicate to different areas than a 1.25wl vertical monopole Hi Jimmie, A low halfwave operates best at 16 degrees; a quarterwave works best in the 20s of degrees; while a 1.25 wavelength antenna works best in the high 50s of degrees. This presumes the last two are both ground mounted. Given that any of these presumptions are at best a guess, then the numbers are merely for guidance as reality may be vastly different (you really haven't given us enough information). Actual physical size and elevation help considerably. Also, as this is 10M, was some of the traffic from the neighborhood (within 20 miles)? 73's Richard Clark, KB7QHC |
#6
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Effects of TOA
I don't know about verticals vs. beams, but certainly you can hear different
areas when using a vertical or using a dipole. I've used both during numerous contests and found that from NC a dipole hears the Caribbean while a vertical hears Argentina, Brazil and points south. This is a G5RV at about 30 feet. The beams hearing ability may wash out this difference, but the "incoming" polarity has nothing to do with the "transmitted" polarity. This is why I have both available. Good luck, Bill, W4WNT "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. Jimmie |
#7
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Effects of TOA
"Richard Clark" wrote in message ... On 13 Apr 2007 16:41:25 -0700, "JIMMIE" wrote: I have observed that a halfwave vertical dipole will communicate to different areas than a 1.25wl vertical monopole Hi Jimmie, A low halfwave operates best at 16 degrees; a quarterwave works best in the 20s of degrees; while a 1.25 wavelength antenna works best in the high 50s of degrees. This presumes the last two are both ground mounted. Given that any of these presumptions are at best a guess, then the numbers are merely for guidance as reality may be vastly different (you really haven't given us enough information). Actual physical size and elevation help considerably. Also, as this is 10M, was some of the traffic from the neighborhood (within 20 miles)? 73's Richard Clark, KB7QHC These are ground mounted monopoles and I am only talking about skip reception. The antennas were mounted on the ground in an attempt to eliminate as much local reception as possible. I am not too interested in the local 10M chatter.not that there is very much but have noticed that the two antennas talk into completely different areas on occasion. I first noticed the phenmena back in the late sixties when I bult a 1.25 wl antena for 11m believing that longer was always better. It was an interesting antenna sometimes allowing me to work into canada from S Ga even when others in the area werent even experiencing skip conditions. I was about 16 at the time but I do seem to remember that hering an opening on this antenna meant that an opening would soon happen for the area. I was wondering if I could duplcate the effect by tilting a yagi to a high angle. The more I think about it I dont belive this would not be practical even if it was possible. Not only would I have to have the antenna tipped at the right time I would also have to have it pointed in the right direction. I would be interested in knowing if others have experienced this effect using unually long vertical antennas on the higher frequencies. |
#8
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Effects of TOA
Thanks , sounds about like what I have been experiencing. The time I heard
the guys in California the band was stone quite and when I switched antennas it was still quite except for the stations in New York Weird feeling. Jimmie "W4WNT" wrote in message ... I don't know about verticals vs. beams, but certainly you can hear different areas when using a vertical or using a dipole. I've used both during numerous contests and found that from NC a dipole hears the Caribbean while a vertical hears Argentina, Brazil and points south. This is a G5RV at about 30 feet. The beams hearing ability may wash out this difference, but the "incoming" polarity has nothing to do with the "transmitted" polarity. This is why I have both available. Good luck, Bill, W4WNT "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. Jimmie |
#9
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Effects of TOA
On Sun, 15 Apr 2007 18:43:12 -0400, "Jimmie D"
wrote: I would be interested in knowing if others have experienced this effect using unually long vertical antennas on the higher frequencies. Hi Jimmie, Sure, and on 10M too. Unfortunately I was the deaf one when others were working the skip. It cuts both ways. 73's Richard Clark, KB7QHC |
#10
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Effects of TOA
"Richard Clark" wrote in message ... On Sun, 15 Apr 2007 18:43:12 -0400, "Jimmie D" wrote: I would be interested in knowing if others have experienced this effect using unually long vertical antennas on the higher frequencies. Hi Jimmie, Sure, and on 10M too. Unfortunately I was the deaf one when others were working the skip. It cuts both ways. 73's Richard Clark, KB7QHC Yeah the 1.25wl vertical want even put a signal across town on most days, it is definatly a specialty antenna. Jimmie |
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