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Vertical Yagi?
Why do we always mount our HF Yagi's in the horizontal plane?
Antenna maintenance would be much easier for those of us with tilt over towers if the antenna were in the horizontal plane when down for maintenance! John Ferrell W8CCW |
Vertical Yagi?
On Jul 12, 2:46 pm, John Ferrell wrote:
Why do we always mount our HF Yagi's in the horizontal plane? Antenna maintenance would be much easier for those of us with tilt over towers if the antenna were in the horizontal plane when down for maintenance! John Ferrell W8CCW John, A local guy has his yagi hinged at the top where the downward pole slips into a "U " shaped clasp. a As his foldover comes down the leverage supplied by the yagi removes the pole from the clasp and the yagi arrives at ground level in a horizontal position |
Vertical Yagi?
"John Ferrell" wrote in message ... Why do we always mount our HF Yagi's in the horizontal plane? Antenna maintenance would be much easier for those of us with tilt over towers if the antenna were in the horizontal plane when down for maintenance! John Ferrell W8CCW vertical yagi's work fine... if you can get them far enough away from the conductive tower and mast either vertically or horizontally... though i do believe you get better ground reflection from the horizontal polarization. There is a new product that allows yagis mounted horizontally to automatically pivot as you tilt over a tower so they stay level with the ground. |
Vertical Yagi?
On Sat, 12 Jul 2008 13:42:36 -0700 (PDT), Art Unwin
wrote: On Jul 12, 2:46 pm, John Ferrell wrote: Why do we always mount our HF Yagi's in the horizontal plane? Antenna maintenance would be much easier for those of us with tilt over towers if the antenna were in the horizontal plane when down for maintenance! John Ferrell W8CCW John, A local guy has his yagi hinged at the top where the downward pole slips into a "U " shaped clasp. a As his foldover comes down the leverage supplied by the yagi removes the pole from the clasp and the yagi arrives at ground level in a horizontal position That is ingenious! I will have to think through the details but I think I can implement it. Keeping weight to a minimum is an important factor. John Ferrell W8CCW |
Vertical Yagi?
On Sun, 13 Jul 2008 00:04:55 GMT, "Dave" wrote:
"John Ferrell" wrote in message .. . Why do we always mount our HF Yagi's in the horizontal plane? Antenna maintenance would be much easier for those of us with tilt over towers if the antenna were in the horizontal plane when down for maintenance! John Ferrell W8CCW vertical yagi's work fine... if you can get them far enough away from the conductive tower and mast either vertically or horizontally... though i do believe you get better ground reflection from the horizontal polarization. There is a new product that allows yagis mounted horizontally to automatically pivot as you tilt over a tower so they stay level with the ground. As soon as I get an opportunity I will rotate mine to vertical at least until I can investigate the possibilities. If you can recall more details of the new product I am interested. The scheme offered by Art sounds like my best bet so far. In the past I have worked from a step ladder with the tower lowered and tilted as far as possible. I did not forsee that two knee joint replacements would take away my use of stepladders for a while! John Ferrell W8CCW |
Vertical Yagi?
On Sun, 13 Jul 2008 00:04:55 GMT, "Dave" wrote:
"John Ferrell" wrote in message .. . Why do we always mount our HF Yagi's in the horizontal plane? Antenna maintenance would be much easier for those of us with tilt over towers if the antenna were in the horizontal plane when down for maintenance! John Ferrell W8CCW vertical yagi's work fine... .... No. Look at the horizontal and vertical diagrams of a Yagi. (Talking about a single Yagi, not stacked) The narrowing of the beam characteristic is only dominant in the horizontal orientation, the vertical retains about the characteristic of a single dipole. So if you tilt a yagi to vertical, it will receive from all directions, especially the EMF noise in your vicinity. When horizontally mounted, it will receive of course from above ( the sky) and from the bottom below your tower but generally there is less interference than in the whole 360 degrees around you. Repeat: the vertical yagi diagram is not much better than that of a single dipole, regardless how many horizontal elements you add in length of the beam. Try it out of you don't believe, but listen to the noise you get, not the signals. Only stacking of yagis can improve the situation. w. |
Vertical Yagi?
hwabnig@ .- --- -. dotat wrote in news:i1bj74h45n3u9redkg4qr1oel8k9nhnqt3@
4ax.com: .... The narrowing of the beam characteristic is only dominant in the horizontal orientation, the vertical retains about the characteristic of a single dipole. That proposition is not born out my models or measurements of real antennas. It is true that the E plane and H plane half power beamwidths are different, but as boom length (gain) is increased, the two approach each other. Owen |
Vertical Yagi?
One of the advantages of a Yagi is its directivity. When mounted
horizontally, its horizontal pattern is quite directional, but the pattern in the vertical plane is relatively broad -- the vertical pattern of a typical HF Yagi in the forward direction, in fact, isn't much different from a single dipole. If you mount the Yagi vertically, the two patterns swap so the horizontal pattern ends up very much broader than when mounted vertically. A vertically mounted Yagi is vertically polarized, and vertically polarized radiation reacts differently with the ground than horizontally polarized radiation. So rotating a moderately or very high yagi from horizontal to vertical will result in loss of low angle radiation unless your ground is very highly conductive. These effects can be very easily be seen by modeling. Roy Lewallen, W7EL John Ferrell wrote: Why do we always mount our HF Yagi's in the horizontal plane? Antenna maintenance would be much easier for those of us with tilt over towers if the antenna were in the horizontal plane when down for maintenance! John Ferrell W8CCW |
Vertical Yagi?
In message , John Ferrell
writes Why do we always mount our HF Yagi's in the horizontal plane? Antenna maintenance would be much easier for those of us with tilt over towers if the antenna were in the horizontal plane when down for maintenance! John Ferrell W8CCW I read somewhere you get more ground gain with horizontal . Something to do with Brewster angle. Brian GM4DIJ -- Brian Howie |
Vertical Yagi?
http://www.nn4zz.com/tiltplate.htm
"Dave" wrote in message news:HEbek.91$kf4.54@trnddc03... "John Ferrell" wrote in message ... Why do we always mount our HF Yagi's in the horizontal plane? Antenna maintenance would be much easier for those of us with tilt over towers if the antenna were in the horizontal plane when down for maintenance! John Ferrell W8CCW vertical yagi's work fine... if you can get them far enough away from the conductive tower and mast either vertically or horizontally... though i do believe you get better ground reflection from the horizontal polarization. There is a new product that allows yagis mounted horizontally to automatically pivot as you tilt over a tower so they stay level with the ground. |
Vertical Yagi?
Roy Lewallen wrote: One of the advantages of a Yagi is its directivity. When mounted horizontally, its horizontal pattern is quite directional, but the pattern in the vertical plane is relatively broad -- the vertical pattern of a typical HF Yagi in the forward direction, in fact, isn't much different from a single dipole. If you mount the Yagi vertically, the two patterns swap so the horizontal pattern ends up very much broader than when mounted vertically. Roy, are you talking about high gain yagis? I just looked at the beamwidths of an 11 element DL6WU Yagi on 2m and got 35 degrees horizontal and 39 degrees vertical in EZNEC. Not much difference there. Alan |
Vertical Yagi?
On Sun, 13 Jul 2008 12:38:20 GMT, "Dave" wrote:
http://www.nn4zz.com/tiltplate.htm That looks like it is real close to what I need! Thanks! John Ferrell W8CCW "Dave" wrote in message news:HEbek.91$kf4.54@trnddc03... "John Ferrell" wrote in message ... Why do we always mount our HF Yagi's in the horizontal plane? Antenna maintenance would be much easier for those of us with tilt over towers if the antenna were in the horizontal plane when down for maintenance! John Ferrell W8CCW vertical yagi's work fine... if you can get them far enough away from the conductive tower and mast either vertically or horizontally... though i do believe you get better ground reflection from the horizontal polarization. There is a new product that allows yagis mounted horizontally to automatically pivot as you tilt over a tower so they stay level with the ground. |
Vertical Yagi?
The EZNEC5 model that I did left me with the feeling that my model was
too vague. John Ferrell W8CCW On Sun, 13 Jul 2008 00:59:30 -0700, Roy Lewallen wrote: One of the advantages of a Yagi is its directivity. When mounted horizontally, its horizontal pattern is quite directional, but the pattern in the vertical plane is relatively broad -- the vertical pattern of a typical HF Yagi in the forward direction, in fact, isn't much different from a single dipole. If you mount the Yagi vertically, the two patterns swap so the horizontal pattern ends up very much broader than when mounted vertically. A vertically mounted Yagi is vertically polarized, and vertically polarized radiation reacts differently with the ground than horizontally polarized radiation. So rotating a moderately or very high yagi from horizontal to vertical will result in loss of low angle radiation unless your ground is very highly conductive. These effects can be very easily be seen by modeling. Roy Lewallen, W7EL John Ferrell wrote: Why do we always mount our HF Yagi's in the horizontal plane? Antenna maintenance would be much easier for those of us with tilt over towers if the antenna were in the horizontal plane when down for maintenance! John Ferrell W8CCW |
Vertical Yagi?
John Ferrell wrote:
Why do we always mount our HF Yagi's in the horizontal plane? Antenna maintenance would be much easier for those of us with tilt over towers if the antenna were in the horizontal plane when down for maintenance! John Ferrell W8CCW Over the past 38 years, I've had HF yagis... a homebrew 3-el 15m monoband yagi (16' boom) and 3-element triband trap yagis (12' booms) on tiltover masts. I've never encountered maintenance issues with operating them in the horizontal plane. A step lader is all that's needed to reach the driven element, and the antenna can be rotated to reach both parasitic elements. It seems to me that while Front/Back ratio might be similar, a vertically polarized yagi would have a significantly reduced Front/Side ratio. If operated in the vertical plane, I'm guessing that performance may also be adversely affected by a conductive mast in the near-field. If performance was same/similar and maintenance was much easier, I think you'd see many more vertically polarized HF yagis. Bryan WA7PRC |
Vertical Yagi?
On Sun, 13 Jul 2008 11:22:44 -0700, "Bryan"
wrote: John Ferrell wrote: Why do we always mount our HF Yagi's in the horizontal plane? Antenna maintenance would be much easier for those of us with tilt over towers if the antenna were in the horizontal plane when down for maintenance! John Ferrell W8CCW Over the past 38 years, I've had HF yagis... a homebrew 3-el 15m monoband yagi (16' boom) and 3-element triband trap yagis (12' booms) on tiltover masts. I've never encountered maintenance issues with operating them in the horizontal plane. A step lader is all that's needed to reach the driven element, and the antenna can be rotated to reach both parasitic elements. It seems to me that while Front/Back ratio might be similar, a vertically polarized yagi would have a significantly reduced Front/Side ratio. If operated in the vertical plane, I'm guessing that performance may also be adversely affected by a conductive mast in the near-field. If performance was same/similar and maintenance was much easier, I think you'd see many more vertically polarized HF yagis. Bryan WA7PRC There have been several very credible posts that have convinced me that I do need to stick with horizontal polarization with the Yagi. Fortunately, the physical limitation of "no ladders" will go away in a few months as I continue my recovery from two knee joint replacements. However, as I get older I may find the limitation returning. I want to be prepared for that time. My antenna is modest in that it is only a Cushcraft A3S and I generally keep the crank up antenna height at about 50 feet. This area (Greensboro NC) does get an occasional hurricane and some ice storms. There are times when I would like to reduce my risks on the forecast weather. I expect I will pursue a lighter (home brew) version of the Tilt Plate system. Currently the coax is fouled at the rotor and I will need outside assistance to clear the problem. It is not a big issue but I do like to solve my own problems! John Ferrell W8CCW |
Vertical Yagi?
Alan Peake wrote:
Roy, are you talking about high gain yagis? I just looked at the beamwidths of an 11 element DL6WU Yagi on 2m and got 35 degrees horizontal and 39 degrees vertical in EZNEC. Not much difference there. Alan No, I'm not. The OP specified HF, so I'm talking about Yagis of up to 5 or 6 elements or so. Ones with a larger number of elements would significantly narrow the pattern in both planes. I'm surprised that the beamwidths approach about the same value, but I haven't done much modeling or any measurement of Yagis with a large number of elements, so I'll believe it. Roy Lewallen, W7EL |
Vertical Yagi?
Alan Peake wrote:
Roy Lewallen wrote: One of the advantages of a Yagi is its directivity. When mounted horizontally, its horizontal pattern is quite directional, but the pattern in the vertical plane is relatively broad -- the vertical pattern of a typical HF Yagi in the forward direction, in fact, isn't much different from a single dipole. If you mount the Yagi vertically, the two patterns swap so the horizontal pattern ends up very much broader than when mounted vertically. Roy, are you talking about high gain yagis? I just looked at the beamwidths of an 11 element DL6WU Yagi on 2m and got 35 degrees horizontal and 39 degrees vertical in EZNEC. Not much difference there. Alan I think he's talking about lower gain (e.g. a 3 element beam for 20m), where the 3dB beamwidth might be about 50-60 degrees in the Eplane (parallel to the elements) and 80 degrees in the H plane (perpendicular to the elements). The 80 is about the same as the 3dB beamwidth of a dipole. For higher gain antennas (e.g. your VHF/UHF), the beamwidths will be pretty close in E and H planes. (since a larger fraction of the overall antenna gain comes from "array pattern" gain rather than the individual "element patterns") Of course, the polarization sensitivity of the ground reflection makes the horizontal antenna usually a winner overall. |
Vertical Yagi?
Roy Lewallen wrote:
Alan Peake wrote: Roy, are you talking about high gain yagis? I just looked at the beamwidths of an 11 element DL6WU Yagi on 2m and got 35 degrees horizontal and 39 degrees vertical in EZNEC. Not much difference there. Alan No, I'm not. The OP specified HF, so I'm talking about Yagis of up to 5 or 6 elements or so. Ones with a larger number of elements would significantly narrow the pattern in both planes. I'm surprised that the beamwidths approach about the same value, but I haven't done much modeling or any measurement of Yagis with a large number of elements, so I'll believe it. Here's a sort of intuitive approach to the conceptual analysis... Consider the overall pattern to be like that of a phased array where you multiply the pattern of an individual element by the pattern of the array assuming that the elements were isotropic. Indeed, in a Yagi, not all the elements are excited equally, but bear with me.. So, in a 3 element antenna with a gain of, say, 5dBi, you're getting about 2 dBi of gain from just the dipoles, and 3dBi of gain from the fact that you've got 3 elements in an array. The beamwidth is going to be a combination of the array pattern (which is the same in vertical and horizontal planes) and the element pattern (which is not).. In a higher gain antenna (say 12dbi), you've got the same element gain 2dBi) but the array pattern gain is now 10dBi, so the shape of the latter will dominate. |
Vertical Yagi?
On Sat, 12 Jul 2008 15:46:27 -0400, John Ferrell
wrote: Why do we always mount our HF Yagi's in the horizontal plane? Antenna maintenance would be much easier for those of us with tilt over towers if the antenna were in the horizontal plane when down for maintenance! John Ferrell W8CCW I sometimes wonder if anybody ever does any actual work or if we just talk about it here. I offer up a progress report here with my work so far on the "Tilt Over Gadget" http://dixienc.us/TiltOverGadget/TiltOverGadget.mht I will concede up front that it is but a crude prototype with some unfinished aspects, but it works! Thanks to all John Ferrell W8CCW |
Vertical Yagi?
John Ferrell wrote:
... I offer up a progress report here with my work so far on the "Tilt Over Gadget" http://dixienc.us/TiltOverGadget/TiltOverGadget.mht I will concede up front that it is but a crude prototype with some unfinished aspects, but it works! Thanks to all John Ferrell W8CCW Whatever that link is to, it will not open in internet explorer or firefox on my computer ... Regards, JS |
Vertical Yagi?
John Smith wrote:
John Ferrell wrote: ... I offer up a progress report here with my work so far on the "Tilt Over Gadget" http://dixienc.us/TiltOverGadget/TiltOverGadget.mht I will concede up front that it is but a crude prototype with some unfinished aspects, but it works! Thanks to all John Ferrell W8CCW Whatever that link is to, it will not open in internet explorer or firefox on my computer ... Regards, JS I stand corrected--I was finally able to get it to load into internet explorer--after three tries! Regards, JS |
Vertical Yagi?
On Tue, 22 Jul 2008 19:07:40 -0700, John Smith
wrote: John Smith wrote: John Ferrell wrote: ... I offer up a progress report here with my work so far on the "Tilt Over Gadget" http://dixienc.us/TiltOverGadget/TiltOverGadget.mht I will concede up front that it is but a crude prototype with some unfinished aspects, but it works! Thanks to all John Ferrell W8CCW Whatever that link is to, it will not open in internet explorer or firefox on my computer ... Regards, JS I stand corrected--I was finally able to get it to load into internet explorer--after three tries! Regards, JS I will try to rework the web page into several smaller pages. I put the page together with Word 2007 as a single file web page. All of the pictures as well as all of the control information is packed into a single (large) file which must be read before the display can start. Since everything is in one file it is easy for me to keep it intact for editing but cumbersome to dwnload... John Ferrell W8CCW |
Vertical Yagi?
I will try to rework the web page into several smaller pages. I put the page together with Word 2007 as a single file web page. All of the pictures as well as all of the control information is packed into a single (large) file which must be read before the display can start. Since everything is in one file it is easy for me to keep it intact for editing but cumbersome to dwnload... John Ferrell W8CCW Good thing. Most standards based web browsers, such as Firefox, Safari etc. do not support this format. I refuse to use Internet Exploder (which seems to have a bunch of non-standard stuff it supports and only it supports) |
Vertical Yagi?
On Wed, 23 Jul 2008 09:25:34 -0400, Jerseyj
wrote: I will try to rework the web page into several smaller pages. I put the page together with Word 2007 as a single file web page. All of the pictures as well as all of the control information is packed into a single (large) file which must be read before the display can start. Since everything is in one file it is easy for me to keep it intact for editing but cumbersome to dwnload... John Ferrell W8CCW Good thing. Most standards based web browsers, such as Firefox, Safari etc. do not support this format. I refuse to use Internet Exploder (which seems to have a bunch of non-standard stuff it supports and only it supports) I am sorry to hear this! The ability to keep everything in a single file greatly simplifies maintenance. I take care of several web sites on a volunteer basis and keeping track of thngs is getting pretty compicated. I will probably go back to Front Page for editing but not uploading. John Ferrell W8CCW |
Vertical Yagi?
( ...Please download a browser that supports Web Archive, such as Windows Internet Explorer. ) John Ferrell W8CCW wrote: I am sorry to hear this! The ability to keep everything in a single file greatly simplifies maintenance. I take care of several web sites on a volunteer basis.... And those websites would be for.... the local Bill Gates Fan Club? |
Vertical Yagi?
On Wed, 23 Jul 2008 09:38:50 -0700, "Jim, K7JEB"
wrote: ( ...Please download a browser that supports Web Archive, such as Windows Internet Explorer. ) John Ferrell W8CCW wrote: I am sorry to hear this! The ability to keep everything in a single file greatly simplifies maintenance. I take care of several web sites on a volunteer basis.... And those websites would be for.... the local Bill Gates Fan Club? If Bill wanted a fan club he would probably just buy one. After all, it really doesn't have to work... It is all here at the moment.... http://dixienc.us/Home.htm John Ferrell W8CCW |
Vertical Yagi?
John Ferrell writes:
On Wed, 23 Jul 2008 09:38:50 -0700, "Jim, K7JEB" wrote: ( ...Please download a browser that supports Web Archive, such as Windows Internet Explorer. ) John Ferrell W8CCW wrote: I am sorry to hear this! The ability to keep everything in a single file greatly simplifies maintenance. I take care of several web sites on a volunteer basis.... And those websites would be for.... the local Bill Gates Fan Club? If Bill wanted a fan club he would probably just buy one. After all, it really doesn't have to work... It is all here at the moment.... http://dixienc.us/Home.htm John Ferrell W8CCW As Microsoftisms go, this one is not among the worst. The format has a standards track Internet RFC (RFC 2557) dating from 1999, and an open Firefox bug dating from the same year. It is also supported by Opera. However, the page doesn't open properly in Opera either. The web server sends the browser the http header line 'Content-Type: text/plain', telling the browser that the format is plain text. So your web server isn't correctly configured for this format. 73 LA4RT Jon |
Vertical Yagi?
In article ,
Jon Kare Hellan wrote: RFC 2557 But as I understand it, this RFC is only standards track, not an approved standard. |
Vertical Yagi?
In article ,
Jon Kare Hellan wrote: http://dixienc.us/Home.htm I just added the UnMHT extension to Firefox and got the same result, I suspect there's a bug in the server. |
Vertical Yagi?
Jerseyj writes:
In article , Jon Kare Hellan wrote: RFC 2557 But as I understand it, this RFC is only standards track, not an approved standard. That's true, but there are surprisingly few actual IETF standards. A lot of the stuff which is expected of a good net citizen is actually just "standards track" or even lower status. |
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