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Post by Afterburner(OT-749) on Jul 2, 2008 15:24:12 GMT -5
First, I want to say that I welcome any and all input to what I am going to ask. OK ... for those of you who have no idea who I am or what I run on this end, for base stations I have Brownings. I usually use one of my MkIII's as a daily talker. On the topside, I have a Moonraker 4 @ about 70 Ft spun around with a Tail Twister. At approx 18 ft above that on the same mast as the Moonraker is a IMAX 2000 NO GPK. For mobile I run an RCI 2950(modified) with a Texas Star 500V talking into a Wilson 1000. Now my question; it has been suggested to me by other's that have said they have done the same to co-phase the vertical side of the Moonraker and the IMAX together. I have no clue if this is feasible or not so that is why I am posing the question. I know that there are others on here that have much better knowledge than I do and probably ever will to give me good advise.  |
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Post by Night Ranger on Jul 2, 2008 17:55:55 GMT -5
First, I want to say that I welcome any and all input to what I am going to ask. OK ... for those of you who have no idea who I am or what I run on this end, for base stations I have Brownings. I usually use one of my MkIII's as a daily talker. On the topside, I have a Moonraker 4 @ about 70 Ft spun around with a Tail Twister. At approx 18 ft above that on the same mast as the Moonraker is a IMAX 2000 NO GPK. For mobile I run an RCI 2950(modified) with a Texas Star 500V talking into a Wilson 1000. Now my question; it has been suggested to me by other's that have said they have done the same to co-phase the vertical side of the Moonraker and the IMAX together. I have no clue if this is feasible or not so that is why I am posing the question. I know that there are others on here that have much better knowledge than I do and probably ever will to give me good advise. Technically it is possible, but doing so would not help your signal. It would detract from the gain of the beam. Mark that one off to CB snake oil. |
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Post by Tombstone (R.I.P.) on Jul 3, 2008 15:38:03 GMT -5
I agree with Nightranger. Cophasing those antennas might work with a lot of effort but I've found that cophasing of any kind really isn't worth it, a good working single antenna will work just as good.
Tombstone
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Post by kosmic on Jul 6, 2008 10:56:45 GMT -5
Sounds to me as though it would be more like using the Imax as a reflector. I have seen this done on 11 meters by some locals and actually it does not work well. Not enough seperation alters the signal. IMHO leave soemthing that works well alone.
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Post by spitfire441 on Jul 6, 2008 23:35:42 GMT -5
Co-Phasing done the right way with the right antennas at the right spacing, works wonders. More capture area and lower angle of radiation is the typical results.
I am now doing experimentation with circular polariztion with my PDL-2 quad. The initial results are very favorable, at least under ionisphereic propagation. I am varying the phase between the vertical and horizontal feeds of the PDL-2. I was seeing at least a 6 db or better, less fadeing signal against an aluminum 5/8 ground plane thats 25 feet higher in elevation.
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Post by Dr. Rigamortis on Jul 16, 2008 7:58:00 GMT -5
I have a co-phasing question. I have seen some pictrures of this in a quad book, but it was discussing using 4 antennas co-phased and not just 2. BUT.... Couldnt you co-phase 2 beams...Moonrakers or what ever on TOP of each other vs side by side?  ?? Huh??? Seperate them on the mast by 18ft or whatever is called for, just stack them verticaly rather than horizontaly. What say you? DR. R. |
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Post by spitfire441 on Jul 18, 2008 15:15:23 GMT -5
Sure you can, best for horizontal polarization is to stack vertically. Also for vertical polarization best to stack horizontal. That said, you can do either way for either one. Make sense? The issue usually comes down to stacking distance available vertically as well as inter action with vertical masting for vert polarization. Unless you use a non-conductive mast,I E fiberglass. It will skew your pattern. Do what works for you. I have lived by that mantra and get a away with some unorthodox stuff somtimes thats works better.
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Post by Tombstone (R.I.P.) on Jul 18, 2008 19:09:02 GMT -5
That an interesting concept and pretty wild but like you say Spitfire, whatever works do it. Sometimes unorthodox methods work well. Theory is one thing but actual use in the field once in awhile throws theory out the window.
Tombstone
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Post by Dr. Rigamortis on Jul 19, 2008 11:32:45 GMT -5
Well I see what your saying, but I actually meant stacking to beams vertically. Put up one beam on a mast, and the other just like it above it vertically. Would that work too?
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Post by spitfire441 on Jul 20, 2008 5:38:44 GMT -5
Well I see what your saying, but I actually meant stacking to beams vertically. Put up one beam on a mast, and the other just like it above it vertically. Would that work too? Yes, you can. However be aware unless you are using wood, or fiberglass or some other non-conductive material you are going to skew your pattern by stacking vertically with vertical beams. You'll have that mast right through the center of one beam. It WILL work, just that you won't get as good a pattern as you would get by horizontally stacking vertical beams. |
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Post by Dr. Rigamortis on Jul 20, 2008 21:58:37 GMT -5
It would be worth playing with I think. Not really sure what it would do for you or make any better. But still it would look impressive.
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Post by marconi390 on Jul 23, 2008 6:04:43 GMT -5
Co-Phasing done the right way with the right antennas at the right spacing, works wonders. More capture area and lower angle of radiation is the typical results. I am now doing experimentation with circular polariztion with my PDL-2 quad. The initial results are very favorable, at least under ionisphereic propagation. I am varying the phase between the vertical and horizontal feeds of the PDL-2. I was seeing at least a 6 db or better, less fadeing signal against an aluminum 5/8 ground plane thats 25 feet higher in elevation. Hey Spitfire, could you talk a little bit about how you did your antenna. It would be nice if you could even give us a photo or two. I saw this discussed somewhere a while back, but I can't find the thread. Good luck in you test. To afterburner, I have never heard of this idea. What is it supposed to do if it works out to actually work? |
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Post by Afterburner(OT-749) on Jul 23, 2008 9:49:51 GMT -5
Truthfully, I have no idea what it is supposed to do for the "transmit" side, but what I have been told is that it will increase the receive side noticeably.
That is why I was posing the question, to hear from others that know more than I do.
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Post by spitfire441 on Jul 23, 2008 17:58:06 GMT -5
Truthfully, I have no idea what it is supposed to do for the "transmit" side, but what I have been told is that it will increase the receive side noticeably. That is why I was posing the question, to hear from others that know more than I do. Something to keep in mind. Whatever is done to an antenna/feedline system works in both directions. In other words, you change your feedline from RG-58 with lots (realitive) of loss, and upgrade to say LMR-400 (low-loss) The gain, or lack of loss is a better term here, is a benifit for both TX and RX. Also applies to antennas, if you go from a 3db gain antenna to a 6db gain antenna (figures for ease of explaination) you will have a 3db gain on TX and RX. Thats why I use the best feedline I can afford with the highest gain antenna I can put up,as high as I can. Sure an amp helps, as well as pre-amps, but I have found the best bang for your buck is always the antenna feedline first. |
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Post by spitfire441 on Jul 23, 2008 18:10:36 GMT -5
Co-Phasing done the right way with the right antennas at the right spacing, works wonders. More capture area and lower angle of radiation is the typical results. I am now doing experimentation with circular polariztion with my PDL-2 quad. The initial results are very favorable, at least under ionisphereic propagation. I am varying the phase between the vertical and horizontal feeds of the PDL-2. I was seeing at least a 6 db or better, less fadeing signal against an aluminum 5/8 ground plane thats 25 feet higher in elevation. Hey Spitfire, could you talk a little bit about how you did your antenna. It would be nice if you could even give us a photo or two. I saw this discussed somewhere a while back, but I can't find the thread. Good luck in you test. To afterburner, I have never heard of this idea. What is it supposed to do if it works out to actually work? Well, if you are familiar with the PDL-2, it has two feed inputs. One for vert, one for horiz. I took a short cut as well as the advantage of ease of "switching" rotation of the circular polarity by useing a Hy-Gain Co-Phaser. www.retrocom.com/ad's&flyers/HY-GAIN%20CO-PHASER.jpg I am using it not as intened. However I have another 5/8 ground plane I plan to put up and use it that way. I need to find another of these units, I like the way the circular polarization is working out. Skywave signals are always better, with less fade than my groundplane. For ground wave the groundplane is the winner for "closer" in stations, however it seems for "farther" out groundwave stations the beam wins, and not all stations are best on any one "rotation" of my polarization. The PDL-2 is at 25 feet above ground, The 5/8 GP is 45 feet above ground. My geography I am sure plays a role here, as I live in a bit of a valley or imagine being inside a volcano crater, I need to shoot out over a "rim" to get out. So I am certain that multi-pathing of signals is gouing on here. Thats why I think my beam is working well at a low hight. I can't wait to get it up at 50 feet or more. |
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?? Huh??? Seperate them on the mast by 18ft or whatever is called for, just stack them verticaly rather than horizontaly. What say you?