Re: Topband: Are stacked verticals feasible?
Isn't this a Vertical dipole? Two quarter wave radiating elements? And tower behind it will be some kind of reflector/director depending on height. The radials seem unimportant if thought of this way. Antennas radiate because of the current flow. So you would have two current maximums, one maximum near the earth for the lower element, and another maximum higher up about 1/4 wave away from earth. The end result would be earth conductivity dependent, but somewhere between a little better or a little worse than a 1/2 wave vertical. The spacing of current maximums would be a little wider than a vertical dipole or half wave vertical, but still too close for any real significant gain. Because a current maximum would be at earth level, ground losses might eat up any very small gain. Maximum stacking gain with 1/4 wave between current maximums is about 0.5 dB. This is reduced because the bottom element is against earth, and could even go negative. Most of any gain, if it had gain, would come from the top element and the earth reflection. _ Topband Reflector
Re: Topband: Are stacked verticals feasible?
Tom and all, If I am reading the question correctly, aren't we talking about something that is done at VHF/UHF with great regularity? Stacked vertical elements, stacked vertically polarized beams and all manner of stacked vertical anything are done there all of the time to avoid cross polarization loss when the other stations (especially mobile) are the main users. So understanding that it is done at those frequencies, the answer to the original question of can it be done, so to speak, is a resounding YES. I just don't have any idea how you could extrapolate that to MF (160 meters).. It would be a monstrously tall structure. he he he. Actually, I have a set of stacked vertical beams that I use for a point-to-point link with a marginal repeater from my cabin up in the high country on the Mogollon Rim in AZ.. It is an incredibly effective antenna that was much less so with a single vertical beam. Hopefully I didn't just waste everyone's time by misinterpreting the question. :) :) Mike AB7ZU Kuhi no ka lima, hele no ka maka On Sep 6, 2013, at 2:46, Tom W8JI w...@w8ji.com wrote: Isn't this a Vertical dipole? Two quarter wave radiating elements? And tower behind it will be some kind of reflector/director depending on height. The radials seem unimportant if thought of this way. Antennas radiate because of the current flow. So you would have two current maximums, one maximum near the earth for the lower element, and another maximum higher up about 1/4 wave away from earth. The end result would be earth conductivity dependent, but somewhere between a little better or a little worse than a 1/2 wave vertical. The spacing of current maximums would be a little wider than a vertical dipole or half wave vertical, but still too close for any real significant gain. Because a current maximum would be at earth level, ground losses might eat up any very small gain. Maximum stacking gain with 1/4 wave between current maximums is about 0.5 dB. This is reduced because the bottom element is against earth, and could even go negative. Most of any gain, if it had gain, would come from the top element and the earth reflection. _ Topband Reflector _ Topband Reflector
Re: Topband: Are stacked verticals feasible?
Hi, Mike When you say that you use stacked vertical beams - aren't they stacked horizontally? It seems to me that the vertical collinear elements,along the lines of what Carl is describing, are generally vertical collinear 1/2 waves in phase - usually with a 1/4 wave phasing line between adjacent vertical elements. Sometimes, the lower element in the array is a 1/4 wave monopole that is part of a ground-plane. Regards, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Mike Armstrong Sent: Friday, September 06, 2013 9:03 AM To: Tom W8JI Cc: topband@contesting.com Subject: Re: Topband: Are stacked verticals feasible? Tom and all, If I am reading the question correctly, aren't we talking about something that is done at VHF/UHF with great regularity? Stacked vertical elements, stacked vertically polarized beams and all manner of stacked vertical anything are done there all of the time to avoid cross polarization loss when the other stations (especially mobile) are the main users. So understanding that it is done at those frequencies, the answer to the original question of can it be done, so to speak, is a resounding YES. I just don't have any idea how you could extrapolate that to MF (160 meters).. It would be a monstrously tall structure. he he he. Actually, I have a set of stacked vertical beams that I use for a point-to-point link with a marginal repeater from my cabin up in the high country on the Mogollon Rim in AZ.. It is an incredibly effective antenna that was much less so with a single vertical beam. Hopefully I didn't just waste everyone's time by misinterpreting the question. :) :) Mike AB7ZU Kuhi no ka lima, hele no ka maka On Sep 6, 2013, at 2:46, Tom W8JI w...@w8ji.com wrote: Isn't this a Vertical dipole? Two quarter wave radiating elements? And tower behind it will be some kind of reflector/director depending on height. The radials seem unimportant if thought of this way. Antennas radiate because of the current flow. So you would have two current maximums, one maximum near the earth for the lower element, and another maximum higher up about 1/4 wave away from earth. The end result would be earth conductivity dependent, but somewhere between a little better or a little worse than a 1/2 wave vertical. The spacing of current maximums would be a little wider than a vertical dipole or half wave vertical, but still too close for any real significant gain. Because a current maximum would be at earth level, ground losses might eat up any very small gain. Maximum stacking gain with 1/4 wave between current maximums is about 0.5 dB. This is reduced because the bottom element is against earth, and could even go negative. Most of any gain, if it had gain, would come from the top element and the earth reflection. _ Topband Reflector _ Topband Reflector _ Topband Reflector
Re: Topband: Are stacked verticals feasible?
Well, if I understand Carl's proposed antenna - he is proposing enough vertical height for two 1/4 wave ground plane antennas, one above the other. In that case I would elect to use a vertical dipole. That would place the current maximum at least a 1/4 wave above ground - reducing the ground losses - and no radials needed. Depending on frequency, Carl's 6-12' spacing from the tower is really tight, and much would depend on the electrical height of the tower. Doesn't sound like a very attractive radiator. I agree with Tom, regarding the stacking gain of the quad. Quads can have other advantages, like less sensitivity to precipitation static, improved bandwidth, reduced turning radias, and more attractive driving point impedances, less corona discharge, but the stacking gain at 1/4 wave spacing is really not significant. Regards, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Tom W8JI Sent: Friday, September 06, 2013 10:01 AM To: topband@contesting.com Subject: Re: Topband: Are stacked verticals feasible? If I am reading the question correctly, aren't we talking about something that is done at VHF/UHF with great regularity? Stacked vertical elements, stacked vertically polarized beams and all manner of stacked vertical anything are done there all of the time to avoid cross polarization loss when the other stations (especially mobile) are the main users. Stacking compresses beamwidth in the plane of the stacking. It's nothing but a collinear antenna placed vertical. Stacking gain depends on individual element directivity and spacing between radiation areas (which are the current maximum areas). Much of the stuff with VHF or UHF Ham antennas is just a gimmick with completely false gain claims. This is because Hams have a false idea that two antennas have 3 dB more gain than one antenna. If we really look at it, spacing has to be pretty wide (typically almost 3/4 wave) with broad pattern antennas like verticals to get near 3 dB, and that would be with zero feedline loss in the stack. It takes a commercial 150 MHz antenna about 20 feet to make 5 dBd gain. It takes a Ham manufacturer less than ten feet to make 6 dB gain. Someone is clearly misleading people, and I doubt it is the commercial people. Directional antennas like Yagi's are even worse. The more directive each stacked cell is, the wider spacing has to be to get near 3 dB gain. In practice, peak stacking gain is rarely over 2 dB. This is especially true if ground gain already compresses the pattern in the same plane as stacking. My 40M stack of two 3-element full size Yagis, spaced optimally with a height limitation of 200-feet, only has about 2 dB stacking gain. That's a lot of work for 2 dB. Adding a third antenna, even going over 300 feet limit, adds even less gain. What mostly makes my 40 meter system work is location and propagation, not the big antennas on a 200 ft tower. Because I'm in a rural location, I can hear and work DX that people with very similar antennas just 20 miles away near populated areas have no hope at all of hearing. I could probably outdo a Yagi stack located in a nearby city area with a regular dipole. Now imagine those quad people who think two half size Yagi's stacked 1/4 wave apart (that's all a quad is) have 2 dB gain! The truth is, the gain is zero to 1 dB depending on height. Gain is all about the spacing between high current areas, and the initial pattern. But results are mostly all about location and local environment. So understanding that it is done at those frequencies, the answer to the original question of can it be done, so to speak, is a resounding YES. I just don't have any idea how you could extrapolate that to MF (160 meters).. It would be a monstrously tall structure. he he he. Actually, I have a set of stacked vertical beams that I use for a point-to-point link with a marginal repeater from my cabin up in the high country on the Mogollon Rim in AZ.. It is an incredibly effective antenna that was much less so with a single vertical beam. Hopefully I didn't just waste everyone's time by misinterpreting the question. :) :) The system described can be done, but the gain would be near zero. The gain could also easily be negative, and with the described scenario, would never be noticeably more than just a regular old vertical dipole. It's a complicated picture, especially when at VHF with multipath. Things often are not what we imagine. 73 Tom _ Topband Reflector _ Topband Reflector
Re: Topband: Are stacked verticals feasible?
Tom, Fully understood. I wasn't referring to the usual collinear antennas sold by comet or anything of that nature. I am referring to the stacking arrangements used for ops like moonbounce, etc. As far as the design theory (and practical application) goes, I have a reasonable amount of schooling and experience (been active since 1966. he he he). Just so you realize I am not referring to the often (always?) false gain claims made by manufacturers for their antenna designs. All I was saying was, yes, it is possible and is done when speaking to vertical stacking. As far as stacking what we would call ground plane antennas (quarter wave vertical element against elevated radials), the only example I have seen with any regularity is done aboard some Naval vessels (stacked/phased, if you will, horizontally on a yard arm). I think I have seen the same thing at airports, but I cannot tell for certain that they are phased arrays or just happen to look like they are related. Understand that in all cases to which I refer, including my own, I am speaking of phased arrays, which I believe is what we are talking about as well. I may have misinterpreted the question to some degree. Again, in my own case, stacking/phasing 4 fairly long beams allowed comms that any other configuration, including a single long boom yagi, did not allow at the same quality level. I never measured the actual gain, but I do know that a single beam didn't cut it. Yes, I could communicate, but with alot of noise into the repeater.. When I stacked them, it became full quieting which is a fairly big difference in quality. I know it wouldn't take much actual gain to make happen, but it does indicate some gain :) :) By the way, it allows me to go simplex into Phoenix from that location on the Rim, as well, with great signals according to the guys I've spoken with. A few tests with a single beam versus a combination of phased beams (2 or 4 beams) indicated the same basic thing according to the folks on the other end. I won't quote what they said concerning s-meter readings because that is pretty meaningless.. BUT, full quieting vs noisy signal does indicate a reasonable gain, even if I don't know the exact numbers. Oh, one thing I didn't mention is that the beams are all homebrew using aluminum booms and elements (plumbers delight construction) and were phased using the proper impedance for the phasing lines. with a large amount of time spent ensuring as little untoward beam coupling as possible (of the type that, as you know, causes real problems when trying to get the impedances and phasing lines to be correct). Basically, I followed some moonbounce array designs from handbooks of the past, with more of today's understanding of proper phasing, if you will. Seems to work well and all indications are that it does, indeed, have fairly significant gain (which is not actually a measured gain, so I cannot speak to how much with any degree of accuracy, as I mentioned above). WHEW, this is more of a book than I intended. LOL LOL. Mike AB7ZU Kuhi no ka lima, hele no ka maka On Sep 6, 2013, at 7:01, Tom W8JI w...@w8ji.com wrote: If I am reading the question correctly, aren't we talking about something that is done at VHF/UHF with great regularity? Stacked vertical elements, stacked vertically polarized beams and all manner of stacked vertical anything are done there all of the time to avoid cross polarization loss when the other stations (especially mobile) are the main users. Stacking compresses beamwidth in the plane of the stacking. It's nothing but a collinear antenna placed vertical. Stacking gain depends on individual element directivity and spacing between radiation areas (which are the current maximum areas). Much of the stuff with VHF or UHF Ham antennas is just a gimmick with completely false gain claims. This is because Hams have a false idea that two antennas have 3 dB more gain than one antenna. If we really look at it, spacing has to be pretty wide (typically almost 3/4 wave) with broad pattern antennas like verticals to get near 3 dB, and that would be with zero feedline loss in the stack. It takes a commercial 150 MHz antenna about 20 feet to make 5 dBd gain. It takes a Ham manufacturer less than ten feet to make 6 dB gain. Someone is clearly misleading people, and I doubt it is the commercial people. Directional antennas like Yagi's are even worse. The more directive each stacked cell is, the wider spacing has to be to get near 3 dB gain. In practice, peak stacking gain is rarely over 2 dB. This is especially true if ground gain already compresses the pattern in the same plane as stacking. My 40M stack of two 3-element full size Yagis, spaced optimally with a height limitation of 200-feet, only has about 2 dB stacking gain. That's a lot of work for 2 dB. Adding a third antenna, even going over 300 feet
Re: Topband: Are stacked verticals feasible?
Oh, I didn't address one comment you made, Tom.. 5/8ths are dogs on 160? Really? That is odd in the extreme to me. I had incredible success with a ground mounted 5/8 on 20 meters while I was stationed in Hawaii. I was rather space limited, so I could only go up and a tower mounted beam was a no fly zone in that particular situation. So, I decided to try the 5/8ths wave vertical and its performance was nothing short of spectacular when compared to a 1/4 under the same circumstances. Not to malign the simple 1/4 wave, but the 5/8ths performance improvement went way beyond what I would have expected.. and my expectations were certainly reasonable. My thinking was that lifting the major current node a bit above ground would probably be an improvement and, to my surprise, that was an understatement in the extreme. I wouldn't want to overblow the results, but I simply couldn't believe how well the antenna performed on 20. To be sure, I was on Oahu out in Iroquois Point housing, which is well situated with regard to the sea (you are basically ON the water in almost all directions). Additionally, I had 60 radials underneath the thing, spread evenly around the base (in straight lines, no bending). So it was definitely an ideal vertical location. But the difference between it and the quarter wave was what truly surprised me (with all else being the same sea water location, number and length of radials, etc). To hear that it doesn't translate to 160 is really a surprise to me.. Tell me more, assuming you did any kind of study into why it didn't seem to work well. I am as interested in why something DIDN'T work as I am in why it does. If for no other reason than to save a few bucks and alot of time LOL Mike AB7ZU Kuhi no ka lima, hele no ka maka On Sep 6, 2013, at 9:25, Tom W8JI w...@w8ji.com wrote: Fully understood. I wasn't referring to the usual collinear antennas sold by comet or anything of that nature. I am referring to the stacking arrangements used for ops like moonbounce, etc. As far as the design theory (and practical application) goes, I have a reasonable amount of schooling and experience (been active since 1966. he he he). Just so you realize I am not referring to the often (always?) false gain claims made by manufacturers for their antenna designs. but this is verticals, and not a narrow BW like a long Yagi. The narrower the pattern of a cell in the stack, the wider minimum useful stacking distance becomes. Also, for 160, antennas are near earth. Earth spoils everything. A 160 antenna at 260 feet is like a two meter antenna at 3.25 feet above ground. All I was saying was, yes, it is possible and is done when speaking to vertical stacking. As far as stacking what we would call ground plane antennas (quarter wave vertical element against elevated radials), the only example I have seen with any regularity is done aboard some Naval vessels (stacked/phased, if you will, horizontally on a yard arm). I think I have seen the same thing at airports, but I cannot tell for certain that they are phased arrays or just happen to look like they are related. Understand that in all cases to which I refer, including my own, I am speaking of phased arrays, which I believe is what we are talking about as well. I may have misinterpreted the question to some degree. This is 160. The distance ratio for the same behavior on two meters is 80:1. If we look at: http://www.w8ji.com/stacking_broadside_collinear.htm we see **freespace** short dipole stacking distances, between current maximums, is 0.35 WL for 1 dB stacking gain. This is for freespace. That means the current maximums have to be .35*160 = 56 meters apart **if** the elements are in freespace. They have to be even further apart if near earth, because the earth reflection already compresses the vertical pattern. I'd guess, for 1 dB stacking gain over a ground mounted vertical (ignoring ground losses), we could move the lower current maximum to about 50 meters above earth and eliminate the upper element. That would pretty much be a vertical dipole. If we wanted to get 2-3 dB gain, we'd probably need 300 feet of height and an inverted groundplane at the top. For 160, is it is a useless endeavor at normal heights. Making matters worse, 5/8th wave verticals are dogs on 160. Been there, done that, used them. A 1/4 wave vertical, or something up to maybe 200 feet, is actually better. They have never worked well here, they never worked when I used broadcast towers, and when W8LT used them in 160 contests they were also pretty weak. The whole thing is a waste of time on 160. Even if someone could run a vertical collinear with useful gain, it would just kill their signal by focusing it at too low an angle for 160, while nulling more useful angles. 73 Tom _ Topband Reflector
Re: Topband: Are stacked verticals feasible?
Oh Tom, I FULLY agree that it would be VERY difficult and not very practical, especially considering we are talking 160.. In fact, the price/performance ratio simply wouldn't be worth it, in my own humble opinion. no doubt about that. There are certainly better ways to get ALOT more gain and probably for alot less money. Real Estate being the real limiter here LOL Mike AB7ZU Kuhi no ka lima, hele no ka maka On Sep 6, 2013, at 9:25, Tom W8JI w...@w8ji.com wrote: Fully understood. I wasn't referring to the usual collinear antennas sold by comet or anything of that nature. I am referring to the stacking arrangements used for ops like moonbounce, etc. As far as the design theory (and practical application) goes, I have a reasonable amount of schooling and experience (been active since 1966. he he he). Just so you realize I am not referring to the often (always?) false gain claims made by manufacturers for their antenna designs. but this is verticals, and not a narrow BW like a long Yagi. The narrower the pattern of a cell in the stack, the wider minimum useful stacking distance becomes. Also, for 160, antennas are near earth. Earth spoils everything. A 160 antenna at 260 feet is like a two meter antenna at 3.25 feet above ground. All I was saying was, yes, it is possible and is done when speaking to vertical stacking. As far as stacking what we would call ground plane antennas (quarter wave vertical element against elevated radials), the only example I have seen with any regularity is done aboard some Naval vessels (stacked/phased, if you will, horizontally on a yard arm). I think I have seen the same thing at airports, but I cannot tell for certain that they are phased arrays or just happen to look like they are related. Understand that in all cases to which I refer, including my own, I am speaking of phased arrays, which I believe is what we are talking about as well. I may have misinterpreted the question to some degree. This is 160. The distance ratio for the same behavior on two meters is 80:1. If we look at: http://www.w8ji.com/stacking_broadside_collinear.htm we see **freespace** short dipole stacking distances, between current maximums, is 0.35 WL for 1 dB stacking gain. This is for freespace. That means the current maximums have to be .35*160 = 56 meters apart **if** the elements are in freespace. They have to be even further apart if near earth, because the earth reflection already compresses the vertical pattern. I'd guess, for 1 dB stacking gain over a ground mounted vertical (ignoring ground losses), we could move the lower current maximum to about 50 meters above earth and eliminate the upper element. That would pretty much be a vertical dipole. If we wanted to get 2-3 dB gain, we'd probably need 300 feet of height and an inverted groundplane at the top. For 160, is it is a useless endeavor at normal heights. Making matters worse, 5/8th wave verticals are dogs on 160. Been there, done that, used them. A 1/4 wave vertical, or something up to maybe 200 feet, is actually better. They have never worked well here, they never worked when I used broadcast towers, and when W8LT used them in 160 contests they were also pretty weak. The whole thing is a waste of time on 160. Even if someone could run a vertical collinear with useful gain, it would just kill their signal by focusing it at too low an angle for 160, while nulling more useful angles. 73 Tom _ Topband Reflector
Re: Topband: Stacked verticals
On 09/06/2013 04:13 PM, Edwin Karl wrote: There are several interesting articles if you Google Franklin Antenna they are mechanically BIG and require feeding ingenuity (hams are known for this feature ...) but are stacked verticals, note- phase the top element to avoid cancellation. If memory serves me right WTIC in Hartford phased two of these puppies, but it's been a long time ... 73! ed k0kl _ Topband Reflector Hi Ed, I looked them up and I see their Hartford is the one in CT. I sent them an email asking about their antenna. When/if they reply we might have more details and I'll post anything of interest I get from them. 73, Bill KU8H _ Topband Reflector
Re: Topband: Are stacked verticals feasible?
Guy, I was right across from the small marina you see. The difference I am talking about is the difference between a 5/8ths wave vertical and a quarter wave vertical in the same place. I am not talking about the difference between a vertical next to the sea as compared to a vertical in Arizona.. two different comparisons and I am thinking you are thinking the latter. :) I was responding to Tom saying that a 5/8ths wave doesn't work well on 160, when a ground mounted 5/8 worked so much better than a quarter wave in the same place (relatively speaking). I had both operational at thr same time and would detune them when I used the other.. Again, I was wondering if Tom could explain why it is such a crappy antenna on 160, but a great antenna (when compared to a quarter wave at the same location) when it is on 20 meters. NOT the difference between two antennas in two different geographical locations.. :) Mike AB7ZU Kuhi no ka lima, hele no ka maka On Sep 6, 2013, at 13:38, Guy Olinger K2AV olin...@bellsouth.net wrote: Mike, could you kindly supply the address on Iroquois Point? If it's in the area I'm looking at with Google Earth, the answer why the difference is pretty plain, and points to why such a difference vs. a 160m vertical on rural terra firma. 73, Guy. On Fri, Sep 6, 2013 at 1:30 PM, Mike Armstrong armst...@aol.com wrote: Oh, I didn't address one comment you made, Tom.. 5/8ths are dogs on 160? Really? That is odd in the extreme to me. I had incredible success with a ground mounted 5/8 on 20 meters while I was stationed in Hawaii. I was rather space limited, so I could only go up and a tower mounted beam was a no fly zone in that particular situation. So, I decided to try the 5/8ths wave vertical and its performance was nothing short of spectacular when compared to a 1/4 under the same circumstances. Not to malign the simple 1/4 wave, but the 5/8ths performance improvement went way beyond what I would have expected.. and my expectations were certainly reasonable. My thinking was that lifting the major current node a bit above ground would probably be an improvement and, to my surprise, that was an understatement in the extreme. I wouldn't want to overblow the results, but I simply couldn't believe how well the antenna performed on 20. To be sure, I was on Oahu out in Iroquois Point housing, which is well situated with regard to the sea (you are basically ON the water in almost all directions). Additionally, I had 60 radials underneath the thing, spread evenly around the base (in straight lines, no bending). So it was definitely an ideal vertical location. But the difference between it and the quarter wave was what truly surprised me (with all else being the same sea water location, number and length of radials, etc). To hear that it doesn't translate to 160 is really a surprise to me.. Tell me more, assuming you did any kind of study into why it didn't seem to work well. I am as interested in why something DIDN'T work as I am in why it does. If for no other reason than to save a few bucks and alot of time LOL Mike AB7ZU Kuhi no ka lima, hele no ka maka On Sep 6, 2013, at 9:25, Tom W8JI w...@w8ji.com wrote: Fully understood. I wasn't referring to the usual collinear antennas sold by comet or anything of that nature. I am referring to the stacking arrangements used for ops like moonbounce, etc. As far as the design theory (and practical application) goes, I have a reasonable amount of schooling and experience (been active since 1966. he he he). Just so you realize I am not referring to the often (always?) false gain claims made by manufacturers for their antenna designs. but this is verticals, and not a narrow BW like a long Yagi. The narrower the pattern of a cell in the stack, the wider minimum useful stacking distance becomes. Also, for 160, antennas are near earth. Earth spoils everything. A 160 antenna at 260 feet is like a two meter antenna at 3.25 feet above ground. All I was saying was, yes, it is possible and is done when speaking to vertical stacking. As far as stacking what we would call ground plane antennas (quarter wave vertical element against elevated radials), the only example I have seen with any regularity is done aboard some Naval vessels (stacked/phased, if you will, horizontally on a yard arm). I think I have seen the same thing at airports, but I cannot tell for certain that they are phased arrays or just happen to look like they are related. Understand that in all cases to which I refer, including my own, I am speaking of phased arrays, which I believe is what we are talking about as well. I may have misinterpreted the question to some degree. This is 160. The distance ratio for the same behavior on two meters is 80:1. If we look at:
Re: Topband: Are stacked verticals feasible?
Guy, you aren't reading my emails.. because that question is not appropriate to the conversation. I am NOT, I repeat NOT talking the difference between LOCATIONS, but the difference between ANTENNAS AT THE SAME LOCATION! I am NOT talking about RURAL ANYTHING. That location being on Gannet Avenue across from the Marina that was LITERALLY across the street from my house. I say again, READ MY EMAIL as your question has absolutely NOTHING to do with the conversation. The fact that you sent the same email to me after I answered you tells me that you are not reading what I wrote. I am not being insulting, but if you don't read ALL of what I wrote, you cannot possibly ask a valid question or make any statements about its content. If you read it, you would know that I am not saying ANYTHING about location changes or differences. OF COURSE a sea water location is better than a rural location. THAT fact has nothing to do with the comparisons I am making or asking Tom to discuss. Sorry for the repetition, but I want to make sure that you will see that, even if you don't read this email entirely. Again, no insult intended, but it is tiring trying to respond to someone who isn't reading ALL of what I wrote and jumping to incorrect conclusions as a result. I WILL tell you the address, if you still want to know, after you have read and responded to the content of this email specifically. Mike AB7ZU Kuhi no ka lima, hele no ka maka On Sep 6, 2013, at 13:38, Guy Olinger K2AV olin...@bellsouth.net wrote: Mike, could you kindly supply the address on Iroquois Point? If it's in the area I'm looking at with Google Earth, the answer why the difference is pretty plain, and points to why such a difference vs. a 160m vertical on rural terra firma. 73, Guy. On Fri, Sep 6, 2013 at 1:30 PM, Mike Armstrong armst...@aol.com wrote: Oh, I didn't address one comment you made, Tom.. 5/8ths are dogs on 160? Really? That is odd in the extreme to me. I had incredible success with a ground mounted 5/8 on 20 meters while I was stationed in Hawaii. I was rather space limited, so I could only go up and a tower mounted beam was a no fly zone in that particular situation. So, I decided to try the 5/8ths wave vertical and its performance was nothing short of spectacular when compared to a 1/4 under the same circumstances. Not to malign the simple 1/4 wave, but the 5/8ths performance improvement went way beyond what I would have expected.. and my expectations were certainly reasonable. My thinking was that lifting the major current node a bit above ground would probably be an improvement and, to my surprise, that was an understatement in the extreme. I wouldn't want to overblow the results, but I simply couldn't believe how well the antenna performed on 20. To be sure, I was on Oahu out in Iroquois Point housing, which is well situated with regard to the sea (you are basically ON the water in almost all directions). Additionally, I had 60 radials underneath the thing, spread evenly around the base (in straight lines, no bending). So it was definitely an ideal vertical location. But the difference between it and the quarter wave was what truly surprised me (with all else being the same sea water location, number and length of radials, etc). To hear that it doesn't translate to 160 is really a surprise to me.. Tell me more, assuming you did any kind of study into why it didn't seem to work well. I am as interested in why something DIDN'T work as I am in why it does. If for no other reason than to save a few bucks and alot of time LOL Mike AB7ZU Kuhi no ka lima, hele no ka maka On Sep 6, 2013, at 9:25, Tom W8JI w...@w8ji.com wrote: Fully understood. I wasn't referring to the usual collinear antennas sold by comet or anything of that nature. I am referring to the stacking arrangements used for ops like moonbounce, etc. As far as the design theory (and practical application) goes, I have a reasonable amount of schooling and experience (been active since 1966. he he he). Just so you realize I am not referring to the often (always?) false gain claims made by manufacturers for their antenna designs. but this is verticals, and not a narrow BW like a long Yagi. The narrower the pattern of a cell in the stack, the wider minimum useful stacking distance becomes. Also, for 160, antennas are near earth. Earth spoils everything. A 160 antenna at 260 feet is like a two meter antenna at 3.25 feet above ground. All I was saying was, yes, it is possible and is done when speaking to vertical stacking. As far as stacking what we would call ground plane antennas (quarter wave vertical element against elevated radials), the only example I have seen with any regularity is done aboard some Naval vessels (stacked/phased, if you will, horizontally on a yard arm). I think I have seen the same thing at airports,
Re: Topband: Are stacked verticals feasible?
Like Tom said earlier, it's all about ground loss. Near the sea, a 1/2 or 5/8 wave vertical may perform very differently than a duplicate antenna a long way from the sea. The near-field and far-field losses at the lower angles would be much lower. 73, Mike www.w0btu.com On Fri, Sep 6, 2013 at 7:04 PM, Bob K6UJ k...@pacbell.net wrote: Mike, Tom, W8JI has a comparison between 1/4 wave and 5/8 wave vertical mobile antennas here: http://www.w8ji.com/VHF%20mobile%20vertical.htm He is comparing mobile antennas but it looks like the 5/8 wave can be 2 db better than the 1/4 wave. Looking at the radiation angle graphs it shows the 5/8 has more gain at lower radiation angles in particular. If you were doing your comparison on long haul contacts it makes sense that the 5/8 would do better. Bob K6UJ On Sep 6, 2013, at 4:35 PM, Mike Armstrong wrote: Guy, you aren't reading my emails.. because that question is not appropriate to the conversation. I am NOT, I repeat NOT talking the difference between LOCATIONS, but the difference between ANTENNAS AT THE SAME LOCATION! I am NOT talking about RURAL ANYTHING. That location being on Gannet Avenue across from the Marina that was LITERALLY across the street from my house. I say again, READ MY EMAIL as your question has absolutely NOTHING to do with the conversation. The fact that you sent the same email to me after I answered you tells me that you are not reading what I wrote. I am not being insulting, but if you don't read ALL of what I wrote, you cannot possibly ask a valid question or make any statements about its content. If you read it, you would know that I am not saying ANYTHING about location changes or differences. OF COURSE a sea water location is better than a rural location. THAT fact has nothing to do with the comparisons I am making or asking Tom to discuss. Sorry for the repetition, but I want to make sure that you will see that, even if you don't read this email entirely. Again, no insult intended, but it is tiring trying to respond to someone who isn't reading ALL of what I wrote and jumping to incorrect conclusions as a result. I WILL tell you the address, if you still want to know, after you have read and responded to the content of this email specifically. Mike AB7ZU Kuhi no ka lima, hele no ka maka On Sep 6, 2013, at 13:38, Guy Olinger K2AV olin...@bellsouth.net wrote: Mike, could you kindly supply the address on Iroquois Point? If it's in the area I'm looking at with Google Earth, the answer why the difference is pretty plain, and points to why such a difference vs. a 160m vertical on rural terra firma. 73, Guy. On Fri, Sep 6, 2013 at 1:30 PM, Mike Armstrong armst...@aol.com wrote: Oh, I didn't address one comment you made, Tom.. 5/8ths are dogs on 160? Really? That is odd in the extreme to me. I had incredible success with a ground mounted 5/8 on 20 meters while I was stationed in Hawaii. I was rather space limited, so I could only go up and a tower mounted beam was a no fly zone in that particular situation. So, I decided to try the 5/8ths wave vertical and its performance was nothing short of spectacular when compared to a 1/4 under the same circumstances. Not to malign the simple 1/4 wave, but the 5/8ths performance improvement went way beyond what I would have expected.. and my expectations were certainly reasonable. My thinking was that lifting the major current node a bit above ground would probably be an improvement and, to my surprise, that was an understatement in the extreme. I wouldn't want to overblow the results, but I simply couldn't believe how well the antenna performed on 20. To be sure, I was on Oahu out in Iroquois Point housing, which is well situated with regard to the sea (you are basically ON the water in almost all directions). Additionally, I had 60 radials underneath the thing, spread evenly around the base (in straight lines, no bending). So it was definitely an ideal vertical location. But the difference between it and the quarter wave was what truly surprised me (with all else being the same sea water location, number and length of radials, etc). To hear that it doesn't translate to 160 is really a surprise to me.. Tell me more, assuming you did any kind of study into why it didn't seem to work well. I am as interested in why something DIDN'T work as I am in why it does. If for no other reason than to save a few bucks and alot of time LOL Mike AB7ZU Kuhi no ka lima, hele no ka maka On Sep 6, 2013, at 9:25, Tom W8JI w...@w8ji.com wrote: Fully understood. I wasn't referring to the usual collinear antennas sold by comet or anything of that nature. I am referring to the stacking arrangements used for ops like moonbounce, etc. As far as the design theory (and practical application) goes, I have a
Re: Topband: Are stacked verticals feasible?
On two meters, yes indeed. But we are talking about 160. To quote Tom above: Also, for 160, antennas are near earth. Earth spoils everything. A 160 antenna at 260 feet is like a two meter antenna at 3.25 feet above ground. ... This is 160. The distance ratio for the same behavior on two meters is 80:1. If we look at: http://www.w8ji.com/stacking_broadside_collinear.htm 73, Mike www.w0btu.com On Fri, Sep 6, 2013 at 7:04 PM, Bob K6UJ k...@pacbell.net wrote: http://www.w8ji.com/VHF%20mobile%20vertical.htm He is comparing mobile antennas but it looks like the 5/8 wave can be 2 db better than the 1/4 wave. Looking at the radiation angle graphs it shows the 5/8 has more gain at lower radiation angles in particular. If you were doing your comparison on long haul contacts it makes sense that the 5/8 would do better. _ Topband Reflector
Re: Topband: Are stacked verticals feasible?
Mike, you are answering the wrong question. Guy didn't understand the question at all. I KNOW that sea water is a better ground than dirt.. The comparison I was ALWAYS talking about had NOTHING AT ALL to do with LOCATION! NOTHING! The comparison was a quarter wave vertical compared to a 5/8ths wave vertical IN THE EXACT SAME LOCATION.. Sorry Mike, I am taking it out on you and it wasn't your fault. People are responding who didn't actually read what I wrote, then they comment. and they YOU commented on their comment which had the wrong premise to begin with. I say again, the comparison had nothing to do with the actual location, but rather two different vertical types in the exact same place. Well, ok, a few yards apart, but with the same number of radials and the same seawater location (Iroquois Point Military Housing on Oahu). THe words RURAL or DIRT were used nowhere in my original email. What intrigued me was that I had such a great experience with a 5/8 wave vertical over a 1/4 wave vertical AT THE SAME LOCATION. and on 20 meters. Tom commented that 5/8 waves were basically garbage on 160 and I would like to know why. IF he knew or had a clue as to the why. Then Guy started talking about seawater vs rural dirt and off the entire thread goes in the wrong direction.. a direction that indicated he was reading stuff into my post that just wasn't there. It is exasperating in the extreme to have that happen, then others like yourself are misdirected by their misdirection because you read theirs instead of mine. Not knowing that they actually didn't read what I wrote. NOT YOUR FAULT, but exasperating because I feel compelled to answer you because you were kind enough to provide some details, but details to an issue that I wouldn't have mentioned because I KNOW that salt water is better than dirt. I've lived in Hawaii, within yards of the oce an and then Arizona, which probably has the world's least conductive dirt on the entire planet. My desire IS STILL to have someone who might know give me a clue as to why the 5/8 doesn't work well on 160 when it works so fabulously well on 20 meters (for one band). I use one out here in AZ on 20, too. It has alot of straight copper radials underneath it (60 half-wave long radials to be precise) and it works as well here, anecdotally speaking, as it did in Hawaii. Well, not quite as good, but darned close if you take into account the difference in solar activity, too. When I was on Hawaii, the spots were a whole lot better, even tho they were decreasing, than they are today at the current peak. If peak is the right word for this one. he he he. But I digress I find it interesting that an antenna that appears to work so well on 20 as a ground mounted vertical, can be so bad on 160. I would like to know why. Thanks for responding Mike. I am sure you will get the gist of what I was talking about, now. No insults intended towards anyone, but this does provide a good example of what happens when folks don't read the entire email someone sends and then comment on it... Then others, who have no idea that the person responding didn't read the email all the way thru or thoroughly, respond to the responder.. and away she goes. LOL. I was starting to get a little wound around the axle, but now it is just funny. Between you and me (ha ha ha) I am not going to respond to anything else concerning my email unless someone wants to discuss the question I actually, really and truly had. LOL. Speaking of which, other than the possibility that a 5/8ths wave vertical lays down a very low angle radiation and it is too low for 160 (although, I have to admit that for DX work, that is a hard pill to swallow. but I am NOT an expert on 160, which is why I read the forum comments here in the first place :) :) Like I said, when I replaced the 1/4 wave with the 5/8 wave ground mounted vertical (20 meters only), the unsolicited comments concerning my signal were universally positive. I was one of the early WINLINK stations and my station being in Hawaii at the time was used by MANY, MANY sailboat guys out in the Pacific and, particularly, the Western Pacific. Many of the guys who used my system were former or retired military having a ball sailing the ocean blue.. Anyway, I needed a good, solid performer that, by necessity, had to be omnidirectional in nature. So I tried the 5/8ths and batta-bing, batta-boom I start getting UNSOLICITED reports in my emails that say something to the effect, what did you do? You are definitely stronger in fact, you are downright LOUD now. That kind of report. Again, they didn't have a clue I had recently changed my winlink dedicated system antenna, but all of a sudden I am louder than they are used to hearing me. The only difference was a 5/8 wave radiator as opposed to a 1/4 wave radiator
Re: Topband: Are stacked verticals feasible?
What got my attention was seeing what appears to be stacked groundplanes at the Manchester NH airport. I dont want a collinear or vertical dipole. The basic ollinears are 2 half wave elements fed at the center either vertical or horizontal and go back to the 30's for SWBC and some ham use. In the late 40's and 50's collinear VHF/UHF ham arrays in either polarization were very popular and with reflectors were called bedspring or curtain antennas. I had a 16el 6M, 8 driven and 8 reflectors, collinear up for about 10 years strapped to the side of a tower and aimed at Europe. It consistently outperformed a 7/7 modified Hi Gain stack (24' booms) in signal reports but was noiser on receive due to the broad lobe and poor F/B. There are several 40 and 80M curtains in use and also used on other bands when designed and fed properly. Great for a narrow sector coverage or trying to play king of the hill to EU, VK, etc. Hopefully Ive explained myself sufficiently by now to get some constructive suggestions. - Original Message - From: Mike Armstrong armst...@aol.com To: Tom W8JI w...@w8ji.com Cc: topband@contesting.com Sent: Friday, September 06, 2013 11:16 AM Subject: Re: Topband: Are stacked verticals feasible? Tom, Fully understood. I wasn't referring to the usual collinear antennas sold by comet or anything of that nature. I am referring to the stacking arrangements used for ops like moonbounce, etc. As far as the design theory (and practical application) goes, I have a reasonable amount of schooling and experience (been active since 1966. he he he). Just so you realize I am not referring to the often (always?) false gain claims made by manufacturers for their antenna designs. All I was saying was, yes, it is possible and is done when speaking to vertical stacking. As far as stacking what we would call ground plane antennas (quarter wave vertical element against elevated radials), the only example I have seen with any regularity is done aboard some Naval vessels (stacked/phased, if you will, horizontally on a yard arm). I think I have seen the same thing at airports, but I cannot tell for certain that they are phased arrays or just happen to look like they are related. Understand that in all cases to which I refer, including my own, I am speaking of phased arrays, which I believe is what we are talking about as well. I may have misinterpreted the question to some degree. Again, in my own case, stacking/phasing 4 fairly long beams allowed comms that any other configuration, including a single long boom yagi, did not allow at the same quality level. I never measured the actual gain, but I do know that a single beam didn't cut it. Yes, I could communicate, but with alot of noise into the repeater.. When I stacked them, it became full quieting which is a fairly big difference in quality. I know it wouldn't take much actual gain to make happen, but it does indicate some gain :) :) By the way, it allows me to go simplex into Phoenix from that location on the Rim, as well, with great signals according to the guys I've spoken with. A few tests with a single beam versus a combination of phased beams (2 or 4 beams) indicated the same basic thing according to the folks on the other end. I won't quote what they said concerning s-meter readings because that is pretty meaningless.. BUT, full quieting vs noisy signal does indicate a reasonable gain, even if I don't know the exact numbers. Oh, one thing I didn't mention is that the beams are all homebrew using aluminum booms and elements (plumbers delight construction) and were phased using the proper impedance for the phasing lines. with a large amount of time spent ensuring as little untoward beam coupling as possible (of the type that, as you know, causes real problems when trying to get the impedances and phasing lines to be correct). Basically, I followed some moonbounce array designs from handbooks of the past, with more of today's understanding of proper phasing, if you will. Seems to work well and all indications are that it does, indeed, have fairly significant gain (which is not actually a measured gain, so I cannot speak to how much with any degree of accuracy, as I mentioned above). WHEW, this is more of a book than I intended. LOL LOL. Mike AB7ZU Kuhi no ka lima, hele no ka maka On Sep 6, 2013, at 7:01, Tom W8JI w...@w8ji.com wrote: If I am reading the question correctly, aren't we talking about something that is done at VHF/UHF with great regularity? Stacked vertical elements, stacked vertically polarized beams and all manner of stacked vertical anything are done there all of the time to avoid cross polarization loss when the other stations (especially mobile) are the main users. Stacking compresses beamwidth in the plane of the stacking. It's nothing but a collinear antenna placed vertical. Stacking gain depends on individual element
Re: Topband: data follow up to W4ZV and K2AV comments
I find SNR reports from RBN very useful and RBN a great tool, but you have to understand the numbers and what they really mean. Let me explain that with a real life example. Almost all skywave HF signals are affected by amplitude fading which follows a Rayleigh distribution when plotted against time. I recently made a simple test by transmitting an SSB two-tone signal (with the aid of the two tone audio generator built into the K3) from my EA5 QTH and monitored the received signal at a SDR (WebSDR) receiver in YO-land on 14 MHz (2,500 km path). The transmitted spectrum of this signal is two continuos, equal and constant amplitude carries spaced 1 KHz. You would expect the amplitude of both signals at the remote end equal at all times as they are two carriers separated only by 1 KHz transmitted with equal powers from the same transmitter, same QTH and with the same antenna Well, you were wrong Fading is frequency selective and I found a difference between the amplitude of both signals ranging from -5 to +25 dB (with a mean of roughly 0 dB) over a 140 second time period. The fact the maximum difference is not symetric around 0 dB is just random and due to the limited duration of the experiment. So if I had used single time samples of the amplitude levels from these signals (the data provided in terms of SNR from RBN), I could have estimated a -5 to a +25 dB difference between both signals when the average difference is 0 dB. Remember this is two signals with equal power transmitted from the same TX and antenna, let alone if signals are originated in different transmitters at different locations (and so with a different ionospheres between them) with different antennas and not sampled at exactly the same time instant. So be careful how you interpret the RBN supplied SNR numbers. 73 de Juan EA5RS PS: If someone is interested I can supply the recorded audio of this experiment as well as analysis data from [Tim Duffy] [Permanent Link][Original] To: 'Bill Tippett' btipp...@alum.mit.edu, topband@contesting.com Subject: Re: Topband: data follow up to W4ZV and K2AV comments From: Tim Duffy k...@k3lr.com Reply-to: k...@k3lr.com Date: Wed, 28 Aug 2013 22:02:07 -0400 List-post: topband@contesting.commailto:topband@contesting.com For the record: 40 meter antennas at W3LPL: Two full size 3 ele Yagi's at 190 feet over 100 feet - 48 foot booms. 40 meter antennas at K3LR Three full size 4 ele OWA Yagi's at 260 feet over 190 feet over 118 feet. 48 foot booms. 7 take off angle combinations are available. QSOs for 40 meters in this contest: K3LR 1767 Europe and 144 Asia W3LPL 1686 Europe and 122 Asia 73, Tim K3LR -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Bill Tippett Sent: Wednesday, August 28, 2013 6:17 AM To: topband@contesting.com Subject: Re: Topband: Effect of trees- tree appreciation Long delayed response to http://lists.contesting.com/pipermail/topband/2013-August/041954.html K2AV wrote: By common expectation LPL and LR should have a propagation advantage over NY4A. LPL and LR both have excellent stacked 3 or 4 element 40m yagi's. But note how as the fourth mode is engaged, both LR and LPL fall off because they are not cleanly engaging the mode, most likely because the increasing elevation angle is starting into a notch in the yagi vertical pattern. Also note that NY4A carries the best signal for most of the 24 hours. This is an evaluation of the NY4A 40 EU quad vs. known excellent installations that is hard to argue with. From the ARRL results database, sorted by maximum 40m QSOs (after log-checking): http://bit.ly/19YAF1f don't worry Frank...it's OK :-) RankCall40m QSOs 1. K3LR2000 2. W3LPL 1911 3. WE3C1862 4. KM1W1818 5. NY4A1809 K3LR could be expected to have a higher total because of better prop to JA but the other 4 should have had similar propagation to EU, which would dominate their results. There's more to this story than RBN spots from a single location shows. 73, Bill W4ZV _ Topband Reflector _ Topband Reflector _ Topband Reflector
Re: Topband: Are stacked verticals feasible?
Gee, I wonder if Carl had any idea what a catfight he was going to start, when he began this thread? For my money, if I had enough support height to support two 1/4 wave ground planes, one above the other, I'd install a vertical 1/2 wave dipole and get the current maximum higher above ground to reduce the ground losses. No radials required! But I think Carl's proposed location for the vertical elements 6-12' from the tower face is way too close especially for 160 or 80 meters! Not likely to be a good radiator with a desirable pattern, I expect. Furthermore, the electrical height of the tower would play a very significant role! 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Mike Armstrong Sent: Friday, September 06, 2013 9:46 PM To: Mike Waters Cc: topband Subject: Re: Topband: Are stacked verticals feasible? Mike, you are answering the wrong question. Guy didn't understand the question at all. I KNOW that sea water is a better ground than dirt.. The comparison I was ALWAYS talking about had NOTHING AT ALL to do with LOCATION! NOTHING! The comparison was a quarter wave vertical compared to a 5/8ths wave vertical IN THE EXACT SAME LOCATION.. Sorry Mike, I am taking it out on you and it wasn't your fault. People are responding who didn't actually read what I wrote, then they comment. and they YOU commented on their comment which had the wrong premise to begin with. I say again, the comparison had nothing to do with the actual location, but rather two different vertical types in the exact same place. Well, ok, a few yards apart, but with the same number of radials and the same seawater location (Iroquois Point Military Housing on Oahu). THe words RURAL or DIRT were used nowhere in my original email. What intrigued me was that I had such a great experience with a 5/8 wave vertical over a 1/4 wave vertical AT THE SAME LOCATION. and on 20 meters. Tom commented that 5/8 waves were basically garbage on 160 and I would like to know why. IF he knew or had a clue as to the why. Then Guy started talking about seawater vs rural dirt and off the entire thread goes in the wrong direction.. a direction that indicated he was reading stuff into my post that just wasn't there. It is exasperating in the extreme to have that happen, then others like yourself are misdirected by their misdirection because you read theirs instead of mine. Not knowing that they actually didn't read what I wrote. NOT YOUR FAULT, but exasperating because I feel compelled to answer you because you were kind enough to provide some details, but details to an issue that I wouldn't have mentioned because I KNOW that salt water is better than dirt. I've lived in Hawaii, within yards of the oce an and then Arizona, which probably has the world's least conductive dirt on the entire planet. My desire IS STILL to have someone who might know give me a clue as to why the 5/8 doesn't work well on 160 when it works so fabulously well on 20 meters (for one band). I use one out here in AZ on 20, too. It has alot of straight copper radials underneath it (60 half-wave long radials to be precise) and it works as well here, anecdotally speaking, as it did in Hawaii. Well, not quite as good, but darned close if you take into account the difference in solar activity, too. When I was on Hawaii, the spots were a whole lot better, even tho they were decreasing, than they are today at the current peak. If peak is the right word for this one. he he he. But I digress I find it interesting that an antenna that appears to work so well on 20 as a ground mounted vertical, can be so bad on 160. I would like to know why. Thanks for responding Mike. I am sure you will get the gist of what I was talking about, now. No insults intended towards anyone, but this does provide a good example of what happens when folks don't read the entire email someone sends and then comment on it... Then others, who have no idea that the person responding didn't read the email all the way thru or thoroughly, respond to the responder.. and away she goes. LOL. I was starting to get a little wound around the axle, but now it is just funny. Between you and me (ha ha ha) I am not going to respond to anything else concerning my email unless someone wants to discuss the question I actually, really and truly had. LOL. Speaking of which, other than the possibility that a 5/8ths wave vertical lays down a very low angle radiation and it is too low for 160 (although, I have to admit that for DX work, that is a hard pill to swallow. but I am NOT an expert on 160, which is why I read the forum comments here in the first place :) :) Like I said, when I replaced the 1/4 wave with the 5/8 wave ground mounted vertical (20 meters only), the unsolicited comments concerning my signal were universally positive. I was one of the early WINLINK
Re: Topband: Are stacked verticals feasible?
On 09/06/2013 09:26 AM, ZR wrote: I would think that at 6-12' spacing from the tower it would minimize interaction on 160 or 80? I don't know, Carl. I'll leave it to the experts. What I do know is I have made several attempts to erect a vertical for 80 meters near my 160 meter tower, using the same radial system. At 10 foot spacing from the tower, the base resistance of an 80 meter quarter wave vertical was less than 5 ohms. That to me suggests significant interaction with the tower. At 5 foot spacing the base resistance was less than 2 ohms! I don't have the data handy but I seem to recall having to adjust the length considerably from a quarter wavelength to cancel a reactive component. 73, Paul N1BUG _ Topband Reflector
Re: Topband: Are stacked verticals feasible?
Carl and Charlie, I am not sure it would even be close to practical or even doable, but I remember seeing an old book on verticals written by a prior Navy Captain, I believe. He had a very interesting design for what WE would, today, call a collinear that was 3/4 wave length tall on 20 meters. it was, in reality what looked like half of a double-zepp antenna in a vertical orientation. It intrigued me that it was like a half wave stacked on top of a 1/4 wave worked against ground (normal radial field). The interesting part was how he used a skirt around the middle quarter wavelength portion to produce the the in-phase relationship with the physically lower 1/4 wave. You guys may already know the design I am talking about. I saw that book a long time ago, like back in the late 60's I think. maybe early 70's. I was considering trying to find the article or book whenI was looking for a better vertical for my winlink node on 20 meters. the one I have been talking about. However, I tried the 5/8ths first because I knew how to build one without having to possess any special instructions. It was so successful, that I completely forgot about the collinear. On the other hand, this discussion reminded me of that book and how author raved, a little anyway, over its performance. I remember that the height of the finished antenna for 20 meters was something very close to 50 feet.. and that is not much taller than a 5/8ths. maybe 7 or 8 feet taller. So on 20 it is very doable and, supposedly, it has some reasonable gain for the effort. I would like to find the book because it described a good way to make that all-important s kirt that got the phase correct between the upper half-wave and the lower quarter-wave sections. Due to its relatively tall structure, it probably wouldn't even be possible to build one for 160. at least not by most of us. It would be interesting to see if it has the same problem that Tom was referring to for the 5/8ths. too low radiation angle. I know it isn't supposed to have that secondary lobe that a 5/8ths has.. So maybe it would be an improvement . IF it was even possible to build one. That would be one tall structure on 160 LOL LOL. Still, for someone needing an omni antenna with some gain on the higher HF bands, it might be a decent answer. Never built one, so I really don't know if it really works or not. Although, as I said, that author was a Navy Captain whose job was designing some of the shipboard antenna systems, like the NORD and some other odd ducks Well, odd to those who don't have to build low loss, low band antennas on a floating postage stamp. I know, I know, you might have trouble thinking of something the size of an Aircraft Carrier being referred to as a floating postage stamp, but if you have spent any time at sea on a big deck, you know exactly what I mean by that statement.. he he he he. I really should remember his name, darn it. with all the time I spent on ships at sea working with his designs, it is really sad (bad?) that I don't remember his name.. Paul something? I'll find out. lol Mike AB7ZU Kuhi no ka lima, hele no ka maka On Sep 6, 2013, at 19:03, Charlie Cunningham charlie-cunning...@nc.rr.com wrote: Well, Carl You just proposed a total height of 3/4 wavelength, it seems. Do you have that much height? Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of ZR Sent: Friday, September 06, 2013 9:26 AM To: Shoppa, Tim; topband@contesting.com Subject: Re: Topband: Are stacked verticals feasible? Look at it as 2 ground planes with the lower feed point 1/4 wave above ground along with its elevated radials which should make it pretty much ground independent according to what has been published on here and elsewhere. The second ground plane would be identical with 1/4 wave spacing from the top of the lower antenna or a 1/2 wave between feed points. Then I would think that the ground conductivity at the reflection point would be the only concern as far as efficiency and gain?? If installed as vertical dipoles then there would also have to be additional spacing between them. I would think that at 6-12' spacing from the tower it would minimize interaction on 160 or 80? Does anyone on here have EZNEC and can plot this? Carl KM1H - Original Message - From: Shoppa, Tim tsho...@wmata.com To: Carl k...@jeremy.mv.com; topband@contesting.com Sent: Thursday, September 05, 2013 10:30 PM Subject: Re: Topband: Are stacked verticals feasible? Isn't this a Vertical dipole? Two quarter wave radiating elements? And tower behind it will be some kind of reflector/director depending on height. The radials seem unimportant if thought of this way. Tim N3QE From: Topband [topband-boun...@contesting.com] on
Re: Topband: Are stacked verticals feasible?
Mike, This is the book. http://store.cq-amateur-radio.com/Detail.bok?no=26 73, Tony K4QE On Fri, Sep 6, 2013 at 10:41 PM, Mike Armstrong armst...@aol.com wrote: Carl and Charlie, I am not sure it would even be close to practical or even doable, but I remember seeing an old book on verticals written by a prior Navy Captain, I believe. He had a very interesting design for what WE would, today, call a collinear that was 3/4 wave length tall on 20 meters. it was, in reality what looked like half of a double-zepp antenna in a vertical orientation. It intrigued me that it was like a half wave stacked on top of a 1/4 wave worked against ground (normal radial field). The interesting part was how he used a skirt around the middle quarter wavelength portion to produce the the in-phase relationship with the physically lower 1/4 wave. You guys may already know the design I am talking about. I saw that book a long time ago, like back in the late 60's I think. maybe early 70's. I was considering trying to find the article or book whenI was looking for a better vertical for my winlink node on 20 meters. the one I have been talking about. However, I tried the 5/8ths first because I knew how to build one without having to possess any special instructions. It was so successful, that I completely forgot about the collinear. On the other hand, this discussion reminded me of that book and how author raved, a little anyway, over its performance. I remember that the height of the finished antenna for 20 meters was something very close to 50 feet.. and that is not much taller than a 5/8ths. maybe 7 or 8 feet taller. So on 20 it is very doable and, supposedly, it has some reasonable gain for the effort. I would like to find the book because it described a good way to make that all-important s kirt that got the phase correct between the upper half-wave and the lower quarter-wave sections. Due to its relatively tall structure, it probably wouldn't even be possible to build one for 160. at least not by most of us. It would be interesting to see if it has the same problem that Tom was referring to for the 5/8ths. too low radiation angle. I know it isn't supposed to have that secondary lobe that a 5/8ths has.. So maybe it would be an improvement . IF it was even possible to build one. That would be one tall structure on 160 LOL LOL. Still, for someone needing an omni antenna with some gain on the higher HF bands, it might be a decent answer. Never built one, so I really don't know if it really works or not. Although, as I said, that author was a Navy Captain whose job was designing some of the shipboard antenna systems, like the NORD and some other odd ducks Well, odd to those who don't have to build low loss, low band antennas on a floating postage stamp. I know, I know, you might have trouble thinking of something the size of an Aircraft Carrier being referred to as a floating postage stamp, but if you have spent any time at sea on a big deck, you know exactly what I mean by that statement.. he he he he. I really should remember his name, darn it. with all the time I spent on ships at sea working with his designs, it is really sad (bad?) that I don't remember his name.. Paul something? I'll find out. lol Mike AB7ZU Kuhi no ka lima, hele no ka maka On Sep 6, 2013, at 19:03, Charlie Cunningham charlie-cunning...@nc.rr.com wrote: Well, Carl You just proposed a total height of 3/4 wavelength, it seems. Do you have that much height? Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of ZR Sent: Friday, September 06, 2013 9:26 AM To: Shoppa, Tim; topband@contesting.com Subject: Re: Topband: Are stacked verticals feasible? Look at it as 2 ground planes with the lower feed point 1/4 wave above ground along with its elevated radials which should make it pretty much ground independent according to what has been published on here and elsewhere. The second ground plane would be identical with 1/4 wave spacing from the top of the lower antenna or a 1/2 wave between feed points. Then I would think that the ground conductivity at the reflection point would be the only concern as far as efficiency and gain?? If installed as vertical dipoles then there would also have to be additional spacing between them. I would think that at 6-12' spacing from the tower it would minimize interaction on 160 or 80? Does anyone on here have EZNEC and can plot this? Carl KM1H - Original Message - From: Shoppa, Tim tsho...@wmata.com To: Carl k...@jeremy.mv.com; topband@contesting.com Sent: Thursday, September 05, 2013 10:30 PM Subject: Re: Topband: Are stacked verticals feasible? Isn't this a Vertical dipole? Two quarter wave radiating elements? And tower behind it will be
Re: Topband: Are stacked verticals feasible?
Hi, Mike I remember the guy that you are referring to, but it's been so many years that I don't remember his last name tither. He published a book via either ARRL or CQ mag. A collinear 1/2 wave over a 1/4 wave GP has certainly been done and used commercially at VHF. The skirt can also be replaced with a shorted 1/4 wave phasing line. Well, Tom's tower is probably tall enough - but how in heck would we get the verticals far enough away from the tower?? Charlie, K4OTV -Original Message- From: Mike Armstrong [mailto:armst...@aol.com] Sent: Friday, September 06, 2013 10:42 PM To: Charlie Cunningham Cc: ZR; Shoppa, Tim; topband@contesting.com Subject: Re: Topband: Are stacked verticals feasible? Carl and Charlie, I am not sure it would even be close to practical or even doable, but I remember seeing an old book on verticals written by a prior Navy Captain, I believe. He had a very interesting design for what WE would, today, call a collinear that was 3/4 wave length tall on 20 meters. it was, in reality what looked like half of a double-zepp antenna in a vertical orientation. It intrigued me that it was like a half wave stacked on top of a 1/4 wave worked against ground (normal radial field). The interesting part was how he used a skirt around the middle quarter wavelength portion to produce the the in-phase relationship with the physically lower 1/4 wave. You guys may already know the design I am talking about. I saw that book a long time ago, like back in the late 60's I think. maybe early 70's. I was considering trying to find the article or book whenI was looking for a better vertical for my winlink node on 20 meters. the one I have been talking about. However, I tried the 5/8ths first because I knew how to build one without having to possess any special instructions. It was so successful, that I completely forgot about the collinear. On the other hand, this discussion reminded me of that book and how author raved, a little anyway, over its performance. I remember that the height of the finished antenna for 20 meters was something very close to 50 feet.. and that is not much taller than a 5/8ths. maybe 7 or 8 feet taller. So on 20 it is very doable and, supposedly, it has some reasonable gain for the effort. I would like to find the book because it described a good way to make that all-important skirt that got the phase correct between the upper half-wave and the lower quarter-wave sections. Due to its relatively tall structure, it probably wouldn't even be possible to build one for 160. at least not by most of us. It would be interesting to see if it has the same problem that Tom was referring to for the 5/8ths. too low radiation angle. I know it isn't supposed to have that secondary lobe that a 5/8ths has.. So maybe it would be an improvement . IF it was even possible to build one. That would be one tall structure on 160 LOL LOL. Still, for someone needing an omni antenna with some gain on the higher HF bands, it might be a decent answer. Never built one, so I really don't know if it really works or not. Although, as I said, that author was a Navy Captain whose job was designing some of the shipboard antenna systems, like the NORD and some other odd ducks Well, odd to those who don't have to build low loss, low band antennas on a floating postage stamp. I know, I know, you might have trouble thinking of something the size of an Aircraft Carrier being referred to as a floating postage stamp, but if you have spent any time at sea on a big deck, you know exactly what I mean by that statement.. he he he he. I really should remember his name, darn it. with all the time I spent on ships at sea working with his designs, it is really sad (bad?) that I don't remember his name.. Paul something? I'll find out. lol Mike AB7ZU Kuhi no ka lima, hele no ka maka On Sep 6, 2013, at 19:03, Charlie Cunningham charlie-cunning...@nc.rr.com wrote: Well, Carl You just proposed a total height of 3/4 wavelength, it seems. Do you have that much height? Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of ZR Sent: Friday, September 06, 2013 9:26 AM To: Shoppa, Tim; topband@contesting.com Subject: Re: Topband: Are stacked verticals feasible? Look at it as 2 ground planes with the lower feed point 1/4 wave above ground along with its elevated radials which should make it pretty much ground independent according to what has been published on here and elsewhere. The second ground plane would be identical with 1/4 wave spacing from the top of the lower antenna or a 1/2 wave between feed points. Then I would think that the ground conductivity at the reflection point would be the only concern as far as efficiency and gain?? If installed as vertical dipoles then there would also have to be additional spacing between them. I would think that at 6-12'
Re: Topband: Are stacked verticals feasible?
Thanks, Tony Yes, that's the one! I was pretty sure that it was published by CQ, but I was having a senior moment and couldn't remember Paul's last name! J 73, Charlie, K4OTV From: Anthony Scandurra [mailto:anthony.scandu...@gmail.com] Sent: Friday, September 06, 2013 10:52 PM To: Mike Armstrong Cc: Charlie Cunningham; ZR; topband@contesting.com; Shoppa, Tim Subject: Re: Topband: Are stacked verticals feasible? Mike, This is the book. http://store.cq-amateur-radio.com/Detail.bok?no=26 73, Tony K4QE On Fri, Sep 6, 2013 at 10:41 PM, Mike Armstrong armst...@aol.com wrote: Carl and Charlie, I am not sure it would even be close to practical or even doable, but I remember seeing an old book on verticals written by a prior Navy Captain, I believe. He had a very interesting design for what WE would, today, call a collinear that was 3/4 wave length tall on 20 meters. it was, in reality what looked like half of a double-zepp antenna in a vertical orientation. It intrigued me that it was like a half wave stacked on top of a 1/4 wave worked against ground (normal radial field). The interesting part was how he used a skirt around the middle quarter wavelength portion to produce the the in-phase relationship with the physically lower 1/4 wave. You guys may already know the design I am talking about. I saw that book a long time ago, like back in the late 60's I think. maybe early 70's. I was considering trying to find the article or book whenI was looking for a better vertical for my winlink node on 20 meters. the one I have been talking about. However, I tried the 5/8ths first because I knew how to build one without having to possess any special instructions. It was so successful, that I completely forgot about the collinear. On the other hand, this discussion reminded me of that book and how author raved, a little anyway, over its performance. I remember that the height of the finished antenna for 20 meters was something very close to 50 feet.. and that is not much taller than a 5/8ths. maybe 7 or 8 feet taller. So on 20 it is very doable and, supposedly, it has some reasonable gain for the effort. I would like to find the book because it described a good way to make that all-important s kirt that got the phase correct between the upper half-wave and the lower quarter-wave sections. Due to its relatively tall structure, it probably wouldn't even be possible to build one for 160. at least not by most of us. It would be interesting to see if it has the same problem that Tom was referring to for the 5/8ths. too low radiation angle. I know it isn't supposed to have that secondary lobe that a 5/8ths has.. So maybe it would be an improvement . IF it was even possible to build one. That would be one tall structure on 160 LOL LOL. Still, for someone needing an omni antenna with some gain on the higher HF bands, it might be a decent answer. Never built one, so I really don't know if it really works or not. Although, as I said, that author was a Navy Captain whose job was designing some of the shipboard antenna systems, like the NORD and some other odd ducks Well, odd to those who don't have to build low loss, low band antennas on a floating postage stamp. I know, I know, you might have trouble thinking of something the size of an Aircraft Carrier being referred to as a floating postage stamp, but if you have spent any time at sea on a big deck, you know exactly what I mean by that statement.. he he he he. I really should remember his name, darn it. with all the time I spent on ships at sea working with his designs, it is really sad (bad?) that I don't remember his name.. Paul something? I'll find out. lol Mike AB7ZU Kuhi no ka lima, hele no ka maka On Sep 6, 2013, at 19:03, Charlie Cunningham charlie-cunning...@nc.rr.com wrote: Well, Carl You just proposed a total height of 3/4 wavelength, it seems. Do you have that much height? Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of ZR Sent: Friday, September 06, 2013 9:26 AM To: Shoppa, Tim; topband@contesting.com Subject: Re: Topband: Are stacked verticals feasible? Look at it as 2 ground planes with the lower feed point 1/4 wave above ground along with its elevated radials which should make it pretty much ground independent according to what has been published on here and elsewhere. The second ground plane would be identical with 1/4 wave spacing from the top of the lower antenna or a 1/2 wave between feed points. Then I would think that the ground conductivity at the reflection point would be the only concern as far as efficiency and gain?? If installed as vertical dipoles then there would also have to be additional spacing between them. I would think that at 6-12' spacing from the tower it would minimize interaction on 160 or 80? Does anyone on here have EZNEC and can
Re: Topband: Are stacked verticals feasible?
Tony, Thanks...,. that is the one. As I recall a very good book from my youth. It was one of the first antenna books that I remember reading in my early ham years.. I think its original publishing date was after I was first licensed (1960, when I was an ancient 8 years old... LOL). But it couldn't have been too much later than that. Still in production.. Well, that is a good sign :) Mike AB7ZU Kuhi no ka lima, hele no ka maka On Sep 6, 2013, at 19:52, Anthony Scandurra anthony.scandu...@gmail.com wrote: Mike, This is the book. http://store.cq-amateur-radio.com/Detail.bok?no=26 73, Tony K4QE On Fri, Sep 6, 2013 at 10:41 PM, Mike Armstrong armst...@aol.com wrote: Carl and Charlie, I am not sure it would even be close to practical or even doable, but I remember seeing an old book on verticals written by a prior Navy Captain, I believe. He had a very interesting design for what WE would, today, call a collinear that was 3/4 wave length tall on 20 meters. it was, in reality what looked like half of a double-zepp antenna in a vertical orientation. It intrigued me that it was like a half wave stacked on top of a 1/4 wave worked against ground (normal radial field). The interesting part was how he used a skirt around the middle quarter wavelength portion to produce the the in-phase relationship with the physically lower 1/4 wave. You guys may already know the design I am talking about. I saw that book a long time ago, like back in the late 60's I think. maybe early 70's. I was considering trying to find the article or book whenI was looking for a better vertical for my winlink node on 20 meters. the one I have been talking about. However, I tried the 5/8ths first because I knew how to build one without having to possess any special instructions. It was so successful, that I completely forgot about the collinear. On the other hand, this discussion reminded me of that book and how author raved, a little anyway, over its performance. I remember that the height of the finished antenna for 20 meters was something very close to 50 feet.. and that is not much taller than a 5/8ths. maybe 7 or 8 feet taller. So on 20 it is very doable and, supposedly, it has some reasonable gain for the effort. I would like to find the book because it described a good way to make that all-importan t s kirt that got the phase correct between the upper half-wave and the lower quarter-wave sections. Due to its relatively tall structure, it probably wouldn't even be possible to build one for 160. at least not by most of us. It would be interesting to see if it has the same problem that Tom was referring to for the 5/8ths. too low radiation angle. I know it isn't supposed to have that secondary lobe that a 5/8ths has.. So maybe it would be an improvement . IF it was even possible to build one. That would be one tall structure on 160 LOL LOL. Still, for someone needing an omni antenna with some gain on the higher HF bands, it might be a decent answer. Never built one, so I really don't know if it really works or not. Although, as I said, that author was a Navy Captain whose job was designing some of the shipboard antenna systems, like the NORD and some other odd ducks Well, odd to those who don't have to build low loss, low band antennas on a floating postage stamp. I know, I know, you might have trouble thinking of something the size of an Aircraft Carrier being referred to as a floating postage stamp, but if you have spent any time at sea on a big deck, you know exactly what I mean by that statement.. he he he he. I really should remember his name, darn it. with all the time I spent on ships at sea working with his designs, it is really sad (bad?) that I don't remember his name.. Paul something? I'll find out. lol Mike AB7ZU Kuhi no ka lima, hele no ka maka On Sep 6, 2013, at 19:03, Charlie Cunningham charlie-cunning...@nc.rr.com wrote: Well, Carl You just proposed a total height of 3/4 wavelength, it seems. Do you have that much height? Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of ZR Sent: Friday, September 06, 2013 9:26 AM To: Shoppa, Tim; topband@contesting.com Subject: Re: Topband: Are stacked verticals feasible? Look at it as 2 ground planes with the lower feed point 1/4 wave above ground along with its elevated radials which should make it pretty much ground independent according to what has been published on here and elsewhere. The second ground plane would be identical with 1/4 wave spacing from the top of the lower antenna or a 1/2 wave between feed points. Then I would think that the ground conductivity at the reflection point would be the only concern as far as efficiency and gain?? If installed as
Re: Topband: Are stacked verticals feasible?
Hey.. IF the tower is tall enough for that duty (3/4 wave tall), then you could put that skirt on the middle 1/4 wave, as it were, and you got 'er.. Could he be that lucky? I have to admit, other than right this second, I hadn't ever considered that as a possibility. It should work so long as the height is close to correct and whatever is mounted to the top,of the tower doesn't make the structure look too,much larger than it should look for resonance. H Mike AB7ZU Kuhi no ka lima, hele no ka maka On Sep 6, 2013, at 19:58, Charlie Cunningham charlie-cunning...@nc.rr.com wrote: Hi, Mike I remember the guy that you are referring to, but it's been so many years that I don't remember his last name tither. He published a book via either ARRL or CQ mag. A collinear 1/2 wave over a 1/4 wave GP has certainly been done and used commercially at VHF. The skirt can also be replaced with a shorted 1/4 wave phasing line. Well, Tom's tower is probably tall enough - but how in heck would we get the verticals far enough away from the tower?? Charlie, K4OTV -Original Message- From: Mike Armstrong [mailto:armst...@aol.com] Sent: Friday, September 06, 2013 10:42 PM To: Charlie Cunningham Cc: ZR; Shoppa, Tim; topband@contesting.com Subject: Re: Topband: Are stacked verticals feasible? Carl and Charlie, I am not sure it would even be close to practical or even doable, but I remember seeing an old book on verticals written by a prior Navy Captain, I believe. He had a very interesting design for what WE would, today, call a collinear that was 3/4 wave length tall on 20 meters. it was, in reality what looked like half of a double-zepp antenna in a vertical orientation. It intrigued me that it was like a half wave stacked on top of a 1/4 wave worked against ground (normal radial field). The interesting part was how he used a skirt around the middle quarter wavelength portion to produce the the in-phase relationship with the physically lower 1/4 wave. You guys may already know the design I am talking about. I saw that book a long time ago, like back in the late 60's I think. maybe early 70's. I was considering trying to find the article or book whenI was looking for a better vertical for my winlink node on 20 meters. the one I have been talking about. However, I tried the 5/8ths first because I knew how to build one without having to possess any special instructions. It was so successful, that I completely forgot about the collinear. On the other hand, this discussion reminded me of that book and how author raved, a little anyway, over its performance. I remember that the height of the finished antenna for 20 meters was something very close to 50 feet.. and that is not much taller than a 5/8ths. maybe 7 or 8 feet taller. So on 20 it is very doable and, supposedly, it has some reasonable gain for the effort. I would like to find the book because it described a good way to make that all-important skirt that got the phase correct between the upper half-wave and the lower quarter-wave sections. Due to its relatively tall structure, it probably wouldn't even be possible to build one for 160. at least not by most of us. It would be interesting to see if it has the same problem that Tom was referring to for the 5/8ths. too low radiation angle. I know it isn't supposed to have that secondary lobe that a 5/8ths has.. So maybe it would be an improvement . IF it was even possible to build one. That would be one tall structure on 160 LOL LOL. Still, for someone needing an omni antenna with some gain on the higher HF bands, it might be a decent answer. Never built one, so I really don't know if it really works or not. Although, as I said, that author was a Navy Captain whose job was designing some of the shipboard antenna systems, like the NORD and some other odd ducks Well, odd to those who don't have to build low loss, low band antennas on a floating postage stamp. I know, I know, you might have trouble thinking of something the size of an Aircraft Carrier being referred to as a floating postage stamp, but if you have spent any time at sea on a big deck, you know exactly what I mean by that statement.. he he he he. I really should remember his name, darn it. with all the time I spent on ships at sea working with his designs, it is really sad (bad?) that I don't remember his name.. Paul something? I'll find out. lol Mike AB7ZU Kuhi no ka lima, hele no ka maka On Sep 6, 2013, at 19:03, Charlie Cunningham charlie-cunning...@nc.rr.com wrote: Well, Carl You just proposed a total height of 3/4 wavelength, it seems. Do you have that much height? Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of ZR Sent: Friday, September 06, 2013 9:26 AM To: Shoppa, Tim; topband@contesting.com
Re: Topband: Are stacked verticals feasible?
I have the book. It is among the first antenna books I bought in 78 when I was first starting in this hobby. The book is The Amateur Radio Vertical Antenna Handbook by Capt. Paul H. Lee, USN retired N6PL SK. I built one of the 1/2 over 1/4 wave that you gentlemen are talking about for 20m and it worked very well indeed. the sleeve I used was a cage of 8 wires for the middle 1/4 wave section which also gave the phase shift needed. It is not perfect because the sleeve diameter prevents a perfect shift, but a happy medium is possible and it will work. 73 es DX Pat H. Armstrong KF5YZ PS I have a son named Mike Mike Armstrong armst...@aol.com wrote: Hey.. IF the tower is tall enough for that duty (3/4 wave tall), then you could put that skirt on the middle 1/4 wave, as it were, and you got 'er.. Could he be that lucky? I have to admit, other than right this second, I hadn't ever considered that as a possibility. It should work so long as the height is close to correct and whatever is mounted to the top,of the tower doesn't make the structure look too,much larger than it should look for resonance. H Mike AB7ZU Kuhi no ka lima, hele no ka maka On Sep 6, 2013, at 19:58, Charlie Cunningham charlie-cunning...@nc.rr.com wrote: Hi, Mike I remember the guy that you are referring to, but it's been so many years that I don't remember his last name tither. He published a book via either ARRL or CQ mag. A collinear 1/2 wave over a 1/4 wave GP has certainly been done and used commercially at VHF. The skirt can also be replaced with a shorted 1/4 wave phasing line. Well, Tom's tower is probably tall enough - but how in heck would we get the verticals far enough away from the tower?? Charlie, K4OTV -Original Message- From: Mike Armstrong [mailto:armst...@aol.com] Sent: Friday, September 06, 2013 10:42 PM To: Charlie Cunningham Cc: ZR; Shoppa, Tim; topband@contesting.com Subject: Re: Topband: Are stacked verticals feasible? Carl and Charlie, I am not sure it would even be close to practical or even doable, but I remember seeing an old book on verticals written by a prior Navy Captain, I believe. He had a very interesting design for what WE would, today, call a collinear that was 3/4 wave length tall on 20 meters. it was, in reality what looked like half of a double-zepp antenna in a vertical orientation. It intrigued me that it was like a half wave stacked on top of a 1/4 wave worked against ground (normal radial field). The interesting part was how he used a skirt around the middle quarter wavelength portion to produce the the in-phase relationship with the physically lower 1/4 wave. You guys may already know the design I am talking about. I saw that book a long time ago, like back in the late 60's I think. maybe early 70's. I was considering trying to find the article or book whenI was looking for a better vertical for my winlink node on 20 meters. the one I have been talking about. However, I tried the 5/8ths first because I knew how to build one without having to possess any special instructions. It was so successful, that I completely forgot about the collinear. On the other hand, this discussion reminded me of that book and how author raved, a little anyway, over its performance. I remember that the height of the finished antenna for 20 meters was something very close to 50 feet.. and that is not much taller than a 5/8ths. maybe 7 or 8 feet taller. So on 20 it is very doable and, supposedly, it has some reasonable gain for the effort. I would like to find the book because it described a good way to make that all-important skirt that got the phase correct between the upper half-wave and the lower quarter-wave sections. Due to its relatively tall structure, it probably wouldn't even be possible to build one for 160. at least not by most of us. It would be interesting to see if it has the same problem that Tom was referring to for the 5/8ths. too low radiation angle. I know it isn't supposed to have that secondary lobe that a 5/8ths has.. So maybe it would be an improvement . IF it was even possible to build one. That would be one tall structure on 160 LOL LOL. Still, for someone needing an omni antenna with some gain on the higher HF bands, it might be a decent answer. Never built one, so I really don't know if it really works or not. Although, as I said, that author was a Navy Captain whose job was designing some of the shipboard antenna systems, like the NORD and some other odd ducks Well, odd to those who don't have to build low loss, low band antennas on a floating postage stamp. I know, I know, you might have trouble thinking of something the size of an Aircraft Carrier being referred to as a floating postage stamp, but if you
Re: Topband: Are stacked verticals feasible?
On 09/06/2013 09:26 AM, ZR wrote: I would think that at 6-12' spacing from the tower it would minimize interaction on 160 or 80? I don't know, Carl. I'll leave it to the experts. What I do know is I have made several attempts to erect a vertical for 80 meters near my 160 meter tower, using the same radial system. At 10 foot spacing from the tower, the base resistance of an 80 meter quarter wave vertical was less than 5 ohms. That to me suggests significant interaction with the tower. At 5 foot spacing the base resistance was less than 2 ohms! Well let's think about that. 10 feet on 160 is exactly like 1.5 inches on 2 meters. Anyone really think a two meter whip 1.5 inches away from another antenna or tower would have minimal interaction? Actually, 10 feet isn't even minimal interaction on six meters, let alone on 160 meters. I've been all through this collinear stuff and skirt collinear vertical stuff trying to multiband vertical antennas. I even had a 100 foot insulated base tower with a 33 foot skirt, trying to feed it like a collinear on 40 meters. I tried things with WXEZ FM when they had a 355 foot tower in a swamp, I tried things on my towers. All of that stuff goes into the bag of it was a good sounding idea, but a big waste of time. The reality check, even if you have an insulated tower, is: 1.) Really low wave angles stink on 160 meters most of the time 2.) There isn't that much gain there, because we are forcing the field down against earth. Saltwater would be a different thing, as would freespace. 3.) There isn't that much gain there, because the extra antenna is forcing a null (removing power to use at low angles) where a null already exists 4.) As I recall, the optimum current ratio in my 40 meter skirt collinear vertical was around 1.5 or 2:1, with most of the current in the 33 foot skirt. Despite all the effort, it worked much worse than a 40 meter dipole at 80 feet. 5.) My insulated base 318-foot tower was such a useless 160 antenna, I removed and discarded the insulator. It's just a tower now, to hold up horizontal and VHF/UHF antennas. This is the same stuff that happened to W8LT with their balloon or kitetoon antennas over acres of aluminum sheet groundplane. 73 Tom _ Topband Reflector
Topband: Fw: Are stacked verticals feasible?
Say Paul I am going to try the same setup except ground the 80m vertical as a close (5') coupled radiator and see what the feed impedance of the 160 vertical is on 80. It models well... On 09/06/2013 09:26 AM, ZR wrote: I would think that at 6-12' spacing from the tower it would minimize interaction on 160 or 80? I don't know, Carl. I'll leave it to the experts. What I do know is I have made several attempts to erect a vertical for 80 meters near my 160 meter tower, using the same radial system. At 10 foot spacing from the tower, the base resistance of an 80 meter quarter wave vertical was less than 5 ohms. That to me suggests significant interaction with the tower. At 5 foot spacing the base resistance was less than 2 ohms! I don't have the data handy but I seem to recall having to adjust the length considerably from a quarter wavelength to cancel a reactive component. 73, Paul N1BUG _ Topband Reflector _ Topband Reflector
