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Follow up to Spike ;Bent dipoles?
Spike recently commented upon his success with DX by implementing at
the base of his vertical antenna a fan of 300 ground wires pointing in the direction that he wished to work. I've not seen my suggestion before, but why could one not just have a 1/4 wave vertical, with the other 1/4 wave making up the dipole being rotatable for the desired direction of working? |
Follow up to Spike ;Bent dipoles?
"gareth" wrote:
Spike recently commented upon his success with DX by implementing at the base of his vertical antenna a fan of 300 ground wires pointing in the direction that he wished to work. I've not seen my suggestion before, but why could one not just have a 1/4 wave vertical, with the other 1/4 wave making up the dipole being rotatable for the desired direction of working? ***Project Shun Notice*** Gareth Alun Evans G4SDW has been placed under a global shunning order by Project Shun for his continual, deranged trolling. Please help us make Usenet better by not responding to his malicious and lunatic postings. With thanks, Team Project Shun. ***end*** -- STC // M0TEY // twitter.com/ukradioamateur |
Follow up to Spike ;Bent dipoles?
On 11/28/2015 4:11 PM, gareth wrote:
Spike recently commented upon his success with DX by implementing at the base of his vertical antenna a fan of 300 ground wires pointing in the direction that he wished to work. I've not seen my suggestion before, but why could one not just have a 1/4 wave vertical, with the other 1/4 wave making up the dipole being rotatable for the desired direction of working? One could. |
Follow up to Spike ;Bent dipoles?
On 28/11/2015 22:11, gareth wrote:
Spike recently commented upon his success with DX by implementing at the base of his vertical antenna a fan of 300 ground wires pointing in the direction that he wished to work. I've not seen my suggestion before, but why could one not just have a 1/4 wave vertical, with the other 1/4 wave making up the dipole being rotatable for the desired direction of working? This was covered in, IIRC, Pat Hawkers Technical Topics many years ago. The Americans had done some research on this very topic during the Vietnam war, if one bends a vertical dipole so that the two elements are at right angles to each other it is possible it would seem to get some directivity in the direction of the horizontal element. -- Extend ****s law - make 'em wear a cheat sheet 24/7 |
Follow up to Spike ;Bent dipoles?
"Fred Roberts" wrote in message ... On 28/11/2015 22:11, gareth wrote: Spike recently commented upon his success with DX by implementing at the base of his vertical antenna a fan of 300 ground wires pointing in the direction that he wished to work. I've not seen my suggestion before, but why could one not just have a 1/4 wave vertical, with the other 1/4 wave making up the dipole being rotatable for the desired direction of working? This was covered in, IIRC, Pat Hawkers Technical Topics many years ago. The Americans had done some research on this very topic during the Vietnam war, if one bends a vertical dipole so that the two elements are at right angles to each other it is possible it would seem to get some directivity in the direction of the horizontal element. Thinking about how drooping the radials on a ground plane brings the feed impedance from 35 up to 50 ohms, I presume that bending a dipole has the same type of effect of reducing down from 72 ohms? |
Follow up to Spike ;Bent dipoles?
"gareth" wrote:
"Fred Roberts" wrote in message ... On 28/11/2015 22:11, gareth wrote: Spike recently commented upon his success with DX by implementing at the base of his vertical antenna a fan of 300 ground wires pointing in the direction that he wished to work. I've not seen my suggestion before, but why could one not just have a 1/4 wave vertical, with the other 1/4 wave making up the dipole being rotatable for the desired direction of working? This was covered in, IIRC, Pat Hawkers Technical Topics many years ago. The Americans had done some research on this very topic during the Vietnam war, if one bends a vertical dipole so that the two elements are at right angles to each other it is possible it would seem to get some directivity in the direction of the horizontal element. Thinking about how drooping the radials on a ground plane brings the feed impedance from 35 up to 50 ohms, I presume that bending a dipole has the same type of effect of reducing down from 72 ohms? ***Project Shun Notice*** Gareth Alun Evans G4SDW has been placed under a global shunning order by Project Shun for his continual, deranged trolling. Please help us make Usenet better by not responding to his malicious and lunatic postings. With thanks, Team Project Shun. ***end*** -- STC // M0TEY // twitter.com/ukradioamateur |
Follow up to Spike ;Bent dipoles?
On 29/11/2015 12:25, gareth wrote:
Thinking about how drooping the radials on a ground plane brings the feed impedance from 35 up to 50 ohms, I presume that bending a dipole has the same type of effect of reducing down from 72 ohms? A good point and something I hadn't considered! -- Extend ****s law - make 'em wear a cheat sheet 24/7 |
Follow up to Spike ;Bent dipoles?
On 29/11/2015 12:18, Fred Roberts wrote:
On 28/11/2015 22:11, gareth wrote: Spike recently commented upon his success with DX by implementing at the base of his vertical antenna a fan of 300 ground wires pointing in the direction that he wished to work. I've not seen my suggestion before, but why could one not just have a 1/4 wave vertical, with the other 1/4 wave making up the dipole being rotatable for the desired direction of working? This was covered in, IIRC, Pat Hawkers Technical Topics many years ago. The Americans had done some research on this very topic during the Vietnam war, if one bends a vertical dipole so that the two elements are at right angles to each other it is possible it would seem to get some directivity in the direction of the horizontal element. Gareth is missing the point of the multitude of radials, which are there essentially to get the ground in the radial arc looking like a sheet of metal (and thus lowering the angle of the main lobe). Ideally they should run out to 2.5 lambda, but I didn't have enough wire :-( The bent arm of the dipole can't do that, and is essentially a convenient place to attach the coax outer. -- Spike "Crime butchers innocence to secure a throne, and innocence struggles with all its might against the attempts of crime" - Maximilien Robespierre |
Follow up to Spike ;Bent dipoles?
"Fred Roberts" wrote in message
... On 28/11/2015 22:11, gareth wrote: Spike recently commented upon his success with DX by implementing at the base of his vertical antenna a fan of 300 ground wires pointing in the direction that he wished to work. I've not seen my suggestion before, but why could one not just have a 1/4 wave vertical, with the other 1/4 wave making up the dipole being rotatable for the desired direction of working? This was covered in, IIRC, Pat Hawkers Technical Topics many years ago. The Americans had done some research on this very topic during the Vietnam war, if one bends a vertical dipole so that the two elements are at right angles to each other it is possible it would seem to get some directivity in the direction of the horizontal element. As I'm sure we both know, if a horizontal half wave dipole is turned so the element runs east to west, the maximum radiation will be north and south, with nulls to the east and west. If the dipole is now turned vertically, the nulls would be upwards and downwards and the horizontal radiation would be omni-directional. I've not tried this, but my gut feeling is that if the elements were at right angles you would get a combination of the two radiation patterns, hence some degree of directivity in the form of a null in the direction the horizontal element was pointing. -- ;-) .. 73 de Frank Turner-Smith G3VKI - mine's a pint. .. http://turner-smith.uk |
Follow up to Spike ;Bent dipoles?
In message , FranK Turner-Smith G3VKI
writes "Fred Roberts" wrote in message ... On 28/11/2015 22:11, gareth wrote: Spike recently commented upon his success with DX by implementing at the base of his vertical antenna a fan of 300 ground wires pointing in the direction that he wished to work. I've not seen my suggestion before, but why could one not just have a 1/4 wave vertical, with the other 1/4 wave making up the dipole being rotatable for the desired direction of working? This was covered in, IIRC, Pat Hawkers Technical Topics many years ago. The Americans had done some research on this very topic during the Vietnam war, if one bends a vertical dipole so that the two elements are at right angles to each other it is possible it would seem to get some directivity in the direction of the horizontal element. As I'm sure we both know, if a horizontal half wave dipole is turned so the element runs east to west, the maximum radiation will be north and south, with nulls to the east and west. If the dipole is now turned vertically, the nulls would be upwards and downwards and the horizontal radiation would be omni-directional. I've not tried this, but my gut feeling is that if the elements were at right angles you would get a combination of the two radiation patterns, hence some degree of directivity in the form of a null in the direction the horizontal element was pointing. Isn't it the other way around? Think what happens if you start with the radiation diagram of a straight vertical dipole, and then consider what happens when you progressively raise the lower leg. The once-straight halfwave dipole starts to form a V, and in the direction of the legs of the V, the radiation will start to become somewhat more concentrated. Away from the legs of the V, the radiation starts to become more spread out. However, I don't think you can go too far with this reasoning before you start to lose the slight amount of benefit you obtained. -- Ian |
Follow up to Spike ;Bent dipoles?
In message , gareth
writes "Fred Roberts" wrote in message ... On 28/11/2015 22:11, gareth wrote: Spike recently commented upon his success with DX by implementing at the base of his vertical antenna a fan of 300 ground wires pointing in the direction that he wished to work. I've not seen my suggestion before, but why could one not just have a 1/4 wave vertical, with the other 1/4 wave making up the dipole being rotatable for the desired direction of working? This was covered in, IIRC, Pat Hawkers Technical Topics many years ago. The Americans had done some research on this very topic during the Vietnam war, if one bends a vertical dipole so that the two elements are at right angles to each other it is possible it would seem to get some directivity in the direction of the horizontal element. Thinking about how drooping the radials on a ground plane brings the feed impedance from 35 up to 50 ohms, I presume that bending a dipole has the same type of effect of reducing down from 72 ohms? To get near 72 ohms, you would need to have the radials vertically downwards - so essentially you would have the makings of a centre-fed sleeve dipole. However, a side-effect would be that the coax would be fairly lively at RF, and if you didn't want to live with it, additional decoupling would be needed to kill it off. -- Ian |
Follow up to Spike ;Bent dipoles?
In rec.radio.amateur.antenna gareth wrote:
Spike recently commented upon his success with DX by implementing at the base of his vertical antenna a fan of 300 ground wires pointing in the direction that he wished to work. I've not seen my suggestion before, but why could one not just have a 1/4 wave vertical, with the other 1/4 wave making up the dipole being rotatable for the desired direction of working? Out of curiousity, I modeled the following: freq: 14.2 MHz radial height: 3 inches Material: #12 copper ground: average I optimized the radiator and radial lengths for minimum reactance and got: radiator: 196 inches radial: 190.6 inches R: 75 Ohms X: -0.4 Ohms SWR: 1.5 Maximum gain: -1.8 dBi in the direction of the radial and an elevation angle of 30 degrees Reverse gain: -6.8 dBi Polarization: primarily vertical with horizontal lobes 90 degrees to the radial a -15 dB down from the max vertical gain. -- Jim Pennino |
Follow up to Spike ;Bent dipoles?
wrote in message ... In rec.radio.amateur.antenna gareth wrote: Spike recently commented upon his success with DX by implementing at the base of his vertical antenna a fan of 300 ground wires pointing in the direction that he wished to work. I've not seen my suggestion before, but why could one not just have a 1/4 wave vertical, with the other 1/4 wave making up the dipole being rotatable for the desired direction of working? Out of curiousity, I modeled the following: freq: 14.2 MHz radial height: 3 inches Material: #12 copper ground: average I optimized the radiator and radial lengths for minimum reactance and got: radiator: 196 inches radial: 190.6 inches R: 75 Ohms X: -0.4 Ohms SWR: 1.5 Maximum gain: -1.8 dBi in the direction of the radial and an elevation angle of 30 degrees Reverse gain: -6.8 dBi Polarization: primarily vertical with horizontal lobes 90 degrees to the radial a -15 dB down from the max vertical gain. Cool. Any idea what the numbers would be for the 300 radial configuration? |
Follow up to Spike ;Bent dipoles?
In rec.radio.amateur.antenna Wayne wrote:
wrote in message ... In rec.radio.amateur.antenna gareth wrote: Spike recently commented upon his success with DX by implementing at the base of his vertical antenna a fan of 300 ground wires pointing in the direction that he wished to work. I've not seen my suggestion before, but why could one not just have a 1/4 wave vertical, with the other 1/4 wave making up the dipole being rotatable for the desired direction of working? Out of curiousity, I modeled the following: freq: 14.2 MHz radial height: 3 inches Material: #12 copper ground: average I optimized the radiator and radial lengths for minimum reactance and got: radiator: 196 inches radial: 190.6 inches R: 75 Ohms X: -0.4 Ohms SWR: 1.5 Maximum gain: -1.8 dBi in the direction of the radial and an elevation angle of 30 degrees Reverse gain: -6.8 dBi Polarization: primarily vertical with horizontal lobes 90 degrees to the radial a -15 dB down from the max vertical gain. Cool. Any idea what the numbers would be for the 300 radial configuration? Likely not a lot of difference. I could add a few, but not going to spend the time to add 300. -- Jim Pennino |
Follow up to Spike ;Bent dipoles?
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Follow up to Spike ;Bent dipoles?
"Ian Jackson" wrote in message
... In message , FranK Turner-Smith G3VKI writes "Fred Roberts" wrote in message ... On 28/11/2015 22:11, gareth wrote: Spike recently commented upon his success with DX by implementing at the base of his vertical antenna a fan of 300 ground wires pointing in the direction that he wished to work. I've not seen my suggestion before, but why could one not just have a 1/4 wave vertical, with the other 1/4 wave making up the dipole being rotatable for the desired direction of working? This was covered in, IIRC, Pat Hawkers Technical Topics many years ago. The Americans had done some research on this very topic during the Vietnam war, if one bends a vertical dipole so that the two elements are at right angles to each other it is possible it would seem to get some directivity in the direction of the horizontal element. As I'm sure we both know, if a horizontal half wave dipole is turned so the element runs east to west, the maximum radiation will be north and south, with nulls to the east and west. If the dipole is now turned vertically, the nulls would be upwards and downwards and the horizontal radiation would be omni-directional. I've not tried this, but my gut feeling is that if the elements were at right angles you would get a combination of the two radiation patterns, hence some degree of directivity in the form of a null in the direction the horizontal element was pointing. Isn't it the other way around? Think what happens if you start with the radiation diagram of a straight vertical dipole, and then consider what happens when you progressively raise the lower leg. The once-straight halfwave dipole starts to form a V, and in the direction of the legs of the V, the radiation will start to become somewhat more concentrated. Away from the legs of the V, the radiation starts to become more spread out. However, I don't think you can go too far with this reasoning before you start to lose the slight amount of benefit you obtained. Yeah, ****ed again, you're right. Thinking back to the days of band 1 TV aerials (as they were known then), the dipole and reflector "H" array was folded into an "X" which would have worked in the way you describe. Other advantages were a reduction in weight and windage, plus a saving of materials. -- ;-) .. 73 de Frank Turner-Smith G3VKI - mine's a pint. .. http://turner-smith.uk |
Follow up to Spike ;Bent dipoles?
"Paul Cummins" wrote in message
k... In article , (FranK Turner-Smith G3VKI) wrote: If the dipole is now turned vertically, the nulls would be upwards and downwards and the horizontal radiation would be omni-directional. I've not tried this, but my gut feeling is that if the elements were at right angles you would get a combination of the two radiation patterns, hence some degree of directivity in the form of a null in the direction the horizontal element was pointing. The difficulty there being that if you consider the vertical element to be a monopole, and the horizontal element to be a grpundplane, then logic says that the signal will be stronger in the direction of the horizontal element. Think magmounts on cars, for example. This is making my brain hurt, more beer required. If you fold the dipole into a 90 degree "V" The lobe within the V will be concentrated while the other lobe will be spread across 270 degrees instead of 180. This looks like a gain in the 90 degree section of about 3dB. In the case of a Band 1 TV "X" aerial this would give 3dB gain plus the reflector's contribution (if any) at ground level. In the case here, with one leg vertical, the other horizontal the major lobe would fire at 45 degrees from horizontal, with a null at ground level in the direction the horizontal element was pointed. The magmount on a car is a different proposition. Here you have a vertical radiator just above the centre of a large horizontal metal sheet, plus the vertical is normally more than a quarter wave. 5/8 wave being a figure which springs to mind. -- ;-) .. 73 de Frank Turner-Smith G3VKI - mine's a pint. .. http://turner-smith.uk |
Follow up to Spike ;Bent dipoles?
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Follow up to Spike ;Bent dipoles?
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Follow up to Spike ;Bent dipoles?
John S wrote:
On 11/30/2015 11:35 AM, Spike wrote: On 29/11/2015 23:24, wrote: OK, I added radials for a total of 5 in a 45 degree spread and optimized for minimum reactance. radiator: 203 inches, radial: 186 inches, R: 52.4 Ohms, X: 0.4 Ohms SWR: 1.1, Maximum gain: -.18 dBi in the direction of the radial and an elevation angle of 30 degrees, Reverse gain: -3.7 dBi Note with one radial the F/B ratio is about 5 dB and with five radials it is about 3dB. About the only thing I can see worth noting about this antenna is that it shows more radials are better, but everyone already knows that. Imagine a case whereby someone digs up the soil around the base of a vertical antenna, a couple of feet deep and as far out as the antenna is tall. Into this they mix 2 percent of high-aspect-ratio thin conducting fibres, say about a foot long, and then replace the soil. 2 percent of conducting fibres in an essentially non-conducting medium is about the minimum proportion necessary to reach the percolation threshold.. What results from your modelling exercise do you get in this case? Are you unable to model this yourself or are you just trolling? Spike's a long time and well known troll, yes. -- STC // M0TEY // twitter.com/ukradioamateur |
Follow up to Spike ;Bent dipoles?
In rec.radio.amateur.antenna Spike wrote:
On 29/11/2015 23:24, wrote: OK, I added radials for a total of 5 in a 45 degree spread and optimized for minimum reactance. radiator: 203 inches, radial: 186 inches, R: 52.4 Ohms, X: 0.4 Ohms SWR: 1.1, Maximum gain: -.18 dBi in the direction of the radial and an elevation angle of 30 degrees, Reverse gain: -3.7 dBi Note with one radial the F/B ratio is about 5 dB and with five radials it is about 3dB. About the only thing I can see worth noting about this antenna is that it shows more radials are better, but everyone already knows that. Imagine a case whereby someone digs up the soil around the base of a vertical antenna, a couple of feet deep and as far out as the antenna is tall. Into this they mix 2 percent of high-aspect-ratio thin conducting fibres, say about a foot long, and then replace the soil. 2 percent of conducting fibres in an essentially non-conducting medium is about the minimum proportion necessary to reach the percolation threshold.. What results from your modelling exercise do you get in this case? Modeling thing buried in the soil requires professional software that costs on the order of $1,000. To do this with reasonably priced (for a hobby) software requires that effective soil conductivity be determined. Send me either $1,000.00 or the effective soil conductivity and I'll be glad to do it. -- Jim Pennino |
Follow up to Spike ;Bent dipoles?
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Follow up to Spike ;Bent dipoles?
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Follow up to Spike ;Bent dipoles?
In rec.radio.amateur.antenna Spike wrote:
On 30/11/2015 18:34, wrote: In rec.radio.amateur.antenna Spike wrote: Imagine a case whereby someone digs up the soil around the base of a vertical antenna, a couple of feet deep and as far out as the antenna is tall. Into this they mix 2 percent of high-aspect-ratio thin conducting fibres, say about a foot long, and then replace the soil. 2 percent of conducting fibres in an essentially non-conducting medium is about the minimum proportion necessary to reach the percolation threshold.. What results from your modelling exercise do you get in this case? Modeling thing buried in the soil requires professional software that costs on the order of $1,000. To do this with reasonably priced (for a hobby) software requires that effective soil conductivity be determined. Send me either $1,000.00 or the effective soil conductivity and I'll be glad to do it. The effective soil conductivity will be close to the fully conductive value of the fibres - that's what percolation does. The high aspect ratio fibres are a method of achieving that in a poorly conductive medium such as soil. One can not enter text into a model; numbers please. -- Jim Pennino |
Follow up to Spike ;Bent dipoles?
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Follow up to Spike ;Bent dipoles?
In message , Spike
writes On 30/11/2015 23:53, wrote: In rec.radio.amateur.antenna Spike wrote: The effective soil conductivity will be close to the fully conductive value of the fibres - that's what percolation does. The high aspect ratio fibres are a method of achieving that in a poorly conductive medium such as soil. One can not enter text into a model; numbers please. Much of this has already been done, 'this' meaning studying the effects of ground conductivity and number of radials (going up to 64) by N6LF in QEX with the latest version being published in September/October this year. Note for Brian Howie: the study encompasses 472 kHz, and it should be noted that below 1MHz the soil electromagnetic parameters diverge significantly from HF values. This implies that a different approach is needed, and one of the articles looks at this - you might find this of interest. Thanks I've had a look at them . If I ever get round to transmitting there, I'll need a lot of earth. I'm still using my 5 foot loop for receive, but it's now series tuned, rather than parallel with a coupling loop and seems to work a bit better. By coincidence my morning training run took me near the EDN NDB http://www.b-howie.demon.co.uk/lfbcon.htm It's a top loaded vertical, but looking over the fence, I could see a lot green earth wire radials on the surface. It's possible there are buried ones too , but there are only about 6 and they can't be more than 15ft long, Brian -- Brian Howie |
Follow up to Spike ;Bent dipoles?
On 03/12/2015 12:45, Brian Howie wrote:
In message , Spike writes Note for Brian Howie: the study encompasses 472 kHz, and it should be noted that below 1MHz the soil electromagnetic parameters diverge significantly from HF values. This implies that a different approach is needed, and one of the articles looks at this - you might find this of interest. Thanks I've had a look at them . If I ever get round to transmitting there, I'll need a lot of earth. I guess it will need a lot of planning! And wire... I'm still using my 5 foot loop for receive, but it's now series tuned, rather than parallel with a coupling loop and seems to work a bit better. Do you find the S/N is improved with a loop? Have you thought of trying a shielded loop? By coincidence my morning training run took me near the EDN NDB http://www.b-howie.demon.co.uk/lfbcon.htm It's a top loaded vertical, but looking over the fence, I could see a lot green earth wire radials on the surface. It's possible there are buried ones too , but there are only about 6 and they can't be more than 15ft long, For the beacon to be of maximum use, they'll need a good sky-wave signal; it sounds like the visible radials are there to provide a DC path to earth probably in association with a ground spike, rather than for getting the main lobe lowered. -- Spike "Crime butchers innocence to secure a throne, and innocence struggles with all its might against the attempts of crime" - Maximilien Robespierre |
Follow up to Spike ;Bent dipoles?
In rec.radio.amateur.antenna Spike wrote:
On 03/12/2015 12:45, Brian Howie wrote: In message , Spike writes Note for Brian Howie: the study encompasses 472 kHz, and it should be noted that below 1MHz the soil electromagnetic parameters diverge significantly from HF values. This implies that a different approach is needed, and one of the articles looks at this - you might find this of interest. Thanks I've had a look at them . If I ever get round to transmitting there, I'll need a lot of earth. I guess it will need a lot of planning! And wire... I'm still using my 5 foot loop for receive, but it's now series tuned, rather than parallel with a coupling loop and seems to work a bit better. Do you find the S/N is improved with a loop? Have you thought of trying a shielded loop? By coincidence my morning training run took me near the EDN NDB http://www.b-howie.demon.co.uk/lfbcon.htm It's a top loaded vertical, but looking over the fence, I could see a lot green earth wire radials on the surface. It's possible there are buried ones too , but there are only about 6 and they can't be more than 15ft long, For the beacon to be of maximum use, they'll need a good sky-wave signal; it sounds like the visible radials are there to provide a DC path to earth probably in association with a ground spike, rather than for getting the main lobe lowered. Sky wave propagation doesn't happen at those frequencies for all practical purposes. Sky wave propagation was discovered when amateurs started using frequencies greater than 200 meters. -- Jim Pennino |
Follow up to Spike ;Bent dipoles?
On 05/12/2015 03:40, wrote:
In rec.radio.amateur.antenna Spike wrote: On 03/12/2015 12:45, Brian Howie wrote: By coincidence my morning training run took me near the EDN NDB http://www.b-howie.demon.co.uk/lfbcon.htm It's a top loaded vertical, but looking over the fence, I could see a lot green earth wire radials on the surface. It's possible there are buried ones too , but there are only about 6 and they can't be more than 15ft long, For the beacon to be of maximum use, they'll need a good sky-wave signal; it sounds like the visible radials are there to provide a DC path to earth probably in association with a ground spike, rather than for getting the main lobe lowered. Sky wave propagation doesn't happen at those frequencies for all practical purposes. That's amazing. So all those aircraft at 35000 feet in its service area can't hear the beacon? If it didn't have sky wave, it would merely be a ground-wave beacon, not much use as there aren't that many airports within 35 miles of Edinburgh, and the aircraft captains would know where they were anyway. Sky wave propagation was discovered when amateurs started using frequencies greater than 200 meters. What's interesting here is now much of the radiated power goes sky-wards, and how much goes into surface wave. But apparently no-one's ever thought to determine this, so it'll remain a mystery. -- Spike "Crime butchers innocence to secure a throne, and innocence struggles with all its might against the attempts of crime" - Maximilien Robespierre |
Follow up to Spike ;Bent dipoles?
In rec.radio.amateur.antenna Spike wrote:
On 05/12/2015 03:40, wrote: In rec.radio.amateur.antenna Spike wrote: On 03/12/2015 12:45, Brian Howie wrote: By coincidence my morning training run took me near the EDN NDB http://www.b-howie.demon.co.uk/lfbcon.htm It's a top loaded vertical, but looking over the fence, I could see a lot green earth wire radials on the surface. It's possible there are buried ones too , but there are only about 6 and they can't be more than 15ft long, For the beacon to be of maximum use, they'll need a good sky-wave signal; it sounds like the visible radials are there to provide a DC path to earth probably in association with a ground spike, rather than for getting the main lobe lowered. Sky wave propagation doesn't happen at those frequencies for all practical purposes. That's amazing. So all those aircraft at 35000 feet in its service area can't hear the beacon? If it didn't have sky wave, it would merely be a ground-wave beacon, not much use as there aren't that many airports within 35 miles of Edinburgh, and the aircraft captains would know where they were anyway. OK, I see the problem, you don't know what "skywave" means. https://en.wikipedia.org/wiki/Skywave BTW, at 35,000 feet, the propagation mode is line of sight out to 265 miles. Sky wave propagation was discovered when amateurs started using frequencies greater than 200 meters. What's interesting here is now much of the radiated power goes sky-wards, and how much goes into surface wave. But apparently no-one's ever thought to determine this, so it'll remain a mystery. The term for that is the vertical pattern and any antenna analysis program will show it. There have been LOTS of studies to determine the optimum vertical angle for skywave propagation if that is what you are talking about. -- Jim Pennino |
Follow up to Spike ;Bent dipoles?
On 05/12/2015 18:53, wrote:
In rec.radio.amateur.antenna Spike wrote: On 05/12/2015 03:40, wrote: In rec.radio.amateur.antenna Spike wrote: On 03/12/2015 12:45, Brian Howie wrote: By coincidence my morning training run took me near the EDN NDB http://www.b-howie.demon.co.uk/lfbcon.htm It's a top loaded vertical, but looking over the fence, I could see a lot green earth wire radials on the surface. It's possible there are buried ones too , but there are only about 6 and they can't be more than 15ft long, For the beacon to be of maximum use, they'll need a good sky-wave signal; it sounds like the visible radials are there to provide a DC path to earth probably in association with a ground spike, rather than for getting the main lobe lowered. Sky wave propagation doesn't happen at those frequencies for all practical purposes. Tell that to the beacon DX hunters. That's amazing. So all those aircraft at 35000 feet in its service area can't hear the beacon? If it didn't have sky wave, it would merely be a ground-wave beacon, not much use as there aren't that many airports within 35 miles of Edinburgh, and the aircraft captains would know where they were anyway. OK, I see the problem, you don't know what "skywave" means. To be refracted back, the wave has to reach the relevant layer. https://en.wikipedia.org/wiki/Skywave BTW, at 35,000 feet, the propagation mode is line of sight out to 265 miles. And? Sky wave propagation was discovered when amateurs started using frequencies greater than 200 meters. I've known that since 1956, but thanks for the reminder. What's interesting here is now much of the radiated power goes sky-wards, and how much goes into surface wave. But apparently no-one's ever thought to determine this, so it'll remain a mystery. The term for that is the vertical pattern and any antenna analysis program will show it. There have been LOTS of studies to determine the optimum vertical angle for skywave propagation if that is what you are talking about. Nope. -- Spike "Crime butchers innocence to secure a throne, and innocence struggles with all its might against the attempts of crime" - Maximilien Robespierre |
Follow up to Spike ;Bent dipoles?
In rec.radio.amateur.antenna Spike wrote:
On 05/12/2015 18:53, wrote: In rec.radio.amateur.antenna Spike wrote: On 05/12/2015 03:40, wrote: In rec.radio.amateur.antenna Spike wrote: On 03/12/2015 12:45, Brian Howie wrote: By coincidence my morning training run took me near the EDN NDB http://www.b-howie.demon.co.uk/lfbcon.htm It's a top loaded vertical, but looking over the fence, I could see a lot green earth wire radials on the surface. It's possible there are buried ones too , but there are only about 6 and they can't be more than 15ft long, For the beacon to be of maximum use, they'll need a good sky-wave signal; it sounds like the visible radials are there to provide a DC path to earth probably in association with a ground spike, rather than for getting the main lobe lowered. Sky wave propagation doesn't happen at those frequencies for all practical purposes. Tell that to the beacon DX hunters. That is ground wave propagation; I'd give you a link but you obviously prefer to pull crap out of your ass to reading links. That's amazing. So all those aircraft at 35000 feet in its service area can't hear the beacon? If it didn't have sky wave, it would merely be a ground-wave beacon, not much use as there aren't that many airports within 35 miles of Edinburgh, and the aircraft captains would know where they were anyway. OK, I see the problem, you don't know what "skywave" means. To be refracted back, the wave has to reach the relevant layer. Didn't read the link below, did you? https://en.wikipedia.org/wiki/Skywave BTW, at 35,000 feet, the propagation mode is line of sight out to 265 miles. And? And "those aircraft at 35000 feet" are receiving the beacon through line of sight propagation, not skywave. Sky wave propagation was discovered when amateurs started using frequencies greater than 200 meters. I've known that since 1956, but thanks for the reminder. Perhaps you should have read more in 1956 to understand what the term means. What's interesting here is now much of the radiated power goes sky-wards, and how much goes into surface wave. But apparently no-one's ever thought to determine this, so it'll remain a mystery. The term for that is the vertical pattern and any antenna analysis program will show it. There have been LOTS of studies to determine the optimum vertical angle for skywave propagation if that is what you are talking about. Nope. Then you are ignorant of antenna analysis software and vertical radiation patterns? -- Jim Pennino |
Follow up to Spike ;Bent dipoles?
wrote:
In rec.radio.amateur.antenna Spike wrote: On 05/12/2015 18:53, wrote: In rec.radio.amateur.antenna Spike wrote: On 05/12/2015 03:40, wrote: In rec.radio.amateur.antenna Spike wrote: On 03/12/2015 12:45, Brian Howie wrote: By coincidence my morning training run took me near the EDN NDB http://www.b-howie.demon.co.uk/lfbcon.htm It's a top loaded vertical, but looking over the fence, I could see a lot green earth wire radials on the surface. It's possible there are buried ones too , but there are only about 6 and they can't be more than 15ft long, For the beacon to be of maximum use, they'll need a good sky-wave signal; it sounds like the visible radials are there to provide a DC path to earth probably in association with a ground spike, rather than for getting the main lobe lowered. Sky wave propagation doesn't happen at those frequencies for all practical purposes. Tell that to the beacon DX hunters. That is ground wave propagation; I'd give you a link but you obviously prefer to pull crap out of your ass to reading links. That's amazing. So all those aircraft at 35000 feet in its service area can't hear the beacon? If it didn't have sky wave, it would merely be a ground-wave beacon, not much use as there aren't that many airports within 35 miles of Edinburgh, and the aircraft captains would know where they were anyway. OK, I see the problem, you don't know what "skywave" means. To be refracted back, the wave has to reach the relevant layer. Didn't read the link below, did you? https://en.wikipedia.org/wiki/Skywave BTW, at 35,000 feet, the propagation mode is line of sight out to 265 miles. And? And "those aircraft at 35000 feet" are receiving the beacon through line of sight propagation, not skywave. Sky wave propagation was discovered when amateurs started using frequencies greater than 200 meters. I've known that since 1956, but thanks for the reminder. Perhaps you should have read more in 1956 to understand what the term means. What's interesting here is now much of the radiated power goes sky-wards, and how much goes into surface wave. But apparently no-one's ever thought to determine this, so it'll remain a mystery. The term for that is the vertical pattern and any antenna analysis program will show it. There have been LOTS of studies to determine the optimum vertical angle for skywave propagation if that is what you are talking about. Nope. Then you are ignorant of antenna analysis software and vertical radiation patterns? Jim doing a Jeff here and tearing Spike *yet another* new arsehole. Excellent work, OM. -- STC // M0TEY // twitter.com/ukradioamateur |
Follow up to Spike ;Bent dipoles?
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Follow up to Spike ;Bent dipoles?
In rec.radio.amateur.antenna Spike wrote:
On 06/12/2015 00:06, wrote: snip Your problem, or at least one of them, is that your first response included this statement: "Sky wave propagation doesn't happen at those frequencies for all practical purposes." I let this slide in the interests of discussion, but seeing as you wish to nit-pick and be rude, we'll revisit this by my asking you what you meant, as you are implying that there is in fact some form of skywave at these low-MF Aeronautical beacon frequencies. Please explain. I see you finally read the link so now you think you are going to sharp shoot the original post. BTW, "for all practical purposes" is synonymous with "unlikely to ever happen". While doing that, please also explain what you think it is that causes the claimed variations in the ground wave than enable DX beacon hunters to hear such stations at very long ranges. Search for "ground wave propagation" and read up on it. The relevant quotes are he Sky wave propagation doesn't happen at those frequencies for all practical purposes. Tell that to the beacon DX hunters. That is ground wave propagation; I'd give you a link but you obviously prefer to pull crap out of your ass to reading links. TIA -- Jim Pennino |
Follow up to Spike ;Bent dipoles?
On 06/12/2015 18:29, wrote:
In rec.radio.amateur.antenna Spike wrote: On 06/12/2015 00:06, wrote: snip Your problem, or at least one of them, is that your first response included this statement: "Sky wave propagation doesn't happen at those frequencies for all practical purposes." I let this slide in the interests of discussion, but seeing as you wish to nit-pick and be rude, we'll revisit this by my asking you what you meant, as you are implying that there is in fact some form of skywave at these low-MF Aeronautical beacon frequencies. Please explain. I see you finally read the link so now you think you are going to sharp shoot the original post. BTW, "for all practical purposes" is synonymous with "unlikely to ever happen". You don't seem to know whether or not sky-wave exists at these frequencies. 'Practically', sky-wave would be unreliable for NDB working, but that doesn't mean to say sky-waves don't exist. When you make up your mind about the topic, let me know what your answer is. To help you, there is a shed-load of information out there on MF sky-wave propagation. While doing that, please also explain what you think it is that causes the claimed variations in the ground wave than enable DX beacon hunters to hear such stations at very long ranges. Search for "ground wave propagation" and read up on it. I can't take that from someone who doesn't know that sky-wave exists at MF. Your variable ground-wave is a hoot. The relevant quotes are he Sky wave propagation doesn't happen at those frequencies for all practical purposes. Tell that to the beacon DX hunters. That is ground wave propagation; I'd give you a link but you obviously prefer to pull crap out of your ass to reading links. You're a troll, aren't you? -- Spike "Crime butchers innocence to secure a throne, and innocence struggles with all its might against the attempts of crime" - Maximilien Robespierre |
Follow up to Spike ;Bent dipoles?
Spike wrote:
On 06/12/2015 18:29, wrote: In rec.radio.amateur.antenna Spike wrote: On 06/12/2015 00:06, wrote: snip Your problem, or at least one of them, is that your first response included this statement: "Sky wave propagation doesn't happen at those frequencies for all practical purposes." I let this slide in the interests of discussion, but seeing as you wish to nit-pick and be rude, we'll revisit this by my asking you what you meant, as you are implying that there is in fact some form of skywave at these low-MF Aeronautical beacon frequencies. Please explain. I see you finally read the link so now you think you are going to sharp shoot the original post. BTW, "for all practical purposes" is synonymous with "unlikely to ever happen". You don't seem to know whether or not sky-wave exists at these frequencies. 'Practically', sky-wave would be unreliable for NDB working, but that doesn't mean to say sky-waves don't exist. When you make up your mind about the topic, let me know what your answer is. To help you, there is a shed-load of information out there on MF sky-wave propagation. While doing that, please also explain what you think it is that causes the claimed variations in the ground wave than enable DX beacon hunters to hear such stations at very long ranges. Search for "ground wave propagation" and read up on it. I can't take that from someone who doesn't know that sky-wave exists at MF. Your variable ground-wave is a hoot. The relevant quotes are he Sky wave propagation doesn't happen at those frequencies for all practical purposes. Tell that to the beacon DX hunters. That is ground wave propagation; I'd give you a link but you obviously prefer to pull crap out of your ass to reading links. You're a troll, aren't you? Gotten to, and rattled. That new arsehole you've been torn must sting a little, OM! -- STC // M0TEY // twitter.com/ukradioamateur |
Follow up to Spike ;Bent dipoles?
In rec.radio.amateur.antenna Spike wrote:
On 06/12/2015 18:29, wrote: In rec.radio.amateur.antenna Spike wrote: On 06/12/2015 00:06, wrote: snip Your problem, or at least one of them, is that your first response included this statement: "Sky wave propagation doesn't happen at those frequencies for all practical purposes." I let this slide in the interests of discussion, but seeing as you wish to nit-pick and be rude, we'll revisit this by my asking you what you meant, as you are implying that there is in fact some form of skywave at these low-MF Aeronautical beacon frequencies. Please explain. I see you finally read the link so now you think you are going to sharp shoot the original post. BTW, "for all practical purposes" is synonymous with "unlikely to ever happen". You don't seem to know whether or not sky-wave exists at these frequencies. 'Practically', sky-wave would be unreliable for NDB working, but that doesn't mean to say sky-waves don't exist. When you make up your mind about the topic, let me know what your answer is. To help you, there is a shed-load of information out there on MF sky-wave propagation. The term is "skywave" and it is not known to happen below 500 kHz. While doing that, please also explain what you think it is that causes the claimed variations in the ground wave than enable DX beacon hunters to hear such stations at very long ranges. Search for "ground wave propagation" and read up on it. I can't take that from someone who doesn't know that sky-wave exists at MF. Once again, the term is "skywave". Define MF; there is no exact frequency where skywave ceases to exist, but it has not been observed below 500 kHz. That does not mean that under some extreme ionospheric conditions is can not happen, it means no one has ever seen it happen. Your variable ground-wave is a hoot. The term is "ground wave" and ALL propagation modes are variable due to many reasons; a heavy rainstorm will effect ground wave propagation as it changes the ground conductivity. The relevant quotes are he Sky wave propagation doesn't happen at those frequencies for all practical purposes. Tell that to the beacon DX hunters. That is ground wave propagation; I'd give you a link but you obviously prefer to pull crap out of your ass to reading links. You're a troll, aren't you? Says someone that can not even use the correct terms. -- Jim Pennino |
Follow up to Spike ;Bent dipoles?
On Mon, 7 Dec 2015 01:17:34 -0000, wrote:
The term is "skywave" and it is not known to happen below 500 kHz. I beg to differ. The current issue of QEX has an article on a WWVB 60 KHz frequency standard: http://www.arrl.org/files/file/QEX_Next_Issue/2015/Nov-Dec_2015/Magliacane.pdf On Pg 15 is the section on 60 KHz propagation: LF radio propagation is substantially different from that which exists at higher frequencies. Its remarkable stability and reliability have often led to the belief that 60 kHz signals propagate great distances over ground wave paths alone. In reality, a combination of surface wave and D-layer ionospheric paths are responsible for WWVB signal propagation. At night, cosmic background radiation supports a level of D-layer ionization that is sufficient for propagating LF (and lower frequency) radio signals over long distances. Greater D-layer efficiencies and increased effective height with decreased ionization levels contribute to greater signal coverage during the nighttime hours. etc... So, here we have propagation via the ionospheric D-Layer which I believe is considered a skywave. Note that the author talks about measuring broadcast band frequencies to an accuracy 312 micro-hertz, where such things as varying path lengths are important. The wavelength of 60 KHz is about 5 km. The height of the D layer varies from 60 to 90 km or about 12 to 18 wavelengths at 60 KHz. That's too big for a waveguide structure, which suggests that the dominant mode of propagation is skywave, not ground wave. There is no frequency at which ground wave ceases and skywave takes over. There seems to be quite a bit of overlap. Mo https://en.wikipedia.org/wiki/Very_low_frequency#Propagation_characteristics -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
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