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#1
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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 |
#2
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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 |
#4
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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 |
#5
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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 |
#6
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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 |
#7
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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 |
#8
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Follow up to Spike ;Bent dipoles?
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