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Underground Antenna Experiments on 160 meters.
Some years back I buried a 30 metre (60-feet) auminium wire one spade depth in my back garden. Wire was 1.5 mm in diameter. Soil resistivity about 100 ohm-metres. To scientists that's 10 milli-Siemens. The near end of the wire came up in the shack. That's under my kitchen sink. It's still there. Open-circuit at the far end. As a counterpoise, something essential to tune it against, I erected a wire in the form of an inverted-L. This was about 30 feet high and overall length about 140 feet. I chose this length because it fitted nicely into my back garden. The front garden is too short even for an underground antenna. On the 160m band I fed into it about 30 watts from a home-brew transceiver so I can't provide for the record a manufacturer's type and serial number. However I still have the transceiver which can be inspected. Despite a high local noise level of S-6 I was able to communicate up to 60 miles with mobile stations in broad daylight on SSB. After sunset I could easily communicate with most of Europe on CW. I think a record of these buried antenna experiments should be kept for posterity, alongside the famous biblical work of B,L & E. By the way, as you see, I did remember to measure soil resistivity. It was the first thing I did. What buried wire do you think I used to measure it? ---- Reg, G4FGQ |
Reg Edwards wrote: Some years back I buried a 30 metre (60-feet) auminium wire one spade depth in my back garden. Wire was 1.5 mm in diameter. Soil resistivity about 100 ohm-metres. To scientists that's 10 milli-Siemens. The near end of the wire came up in the shack. That's under my kitchen sink. It's still there. Open-circuit at the far end. As a counterpoise, something essential to tune it against, I erected a wire in the form of an inverted-L. This was about 30 feet high and overall length about 140 feet. I chose this length because it fitted nicely into my back garden. The front garden is too short even for an underground antenna. On the 160m band I fed into it about 30 watts from a home-brew transceiver so I can't provide for the record a manufacturer's type and serial number. However I still have the transceiver which can be inspected. Despite a high local noise level of S-6 I was able to communicate up to 60 miles with mobile stations in broad daylight on SSB. After sunset I could easily communicate with most of Europe on CW. I think a record of these buried antenna experiments should be kept for posterity, alongside the famous biblical work of B,L & E. By the way, as you see, I did remember to measure soil resistivity. It was the first thing I did. What buried wire do you think I used to measure it? ---- Reg, G4FGQ Hi Reg, Interesting, but isn't a 30 metre wire more like 100 feet instead of 60 feet? According to the conversions on your programs it is. Did you ever try burying your counterpoise and elevating the buried aluminum wire to see how the results compare? Gary N4AST |
"Reg Edwards"
Some years back I buried a 30 metre (60-feet) auminium wire one spade depth in my back garden. As a counterpoise, something essential to tune it against, I erected a wire in the form of an inverted-L. This was about 30 feet high and overall length about 140 feet. I think a record of these buried antenna experiments should be kept for posterity, alongside the famous biblical work of B,L & E. ____________ So you loaded your tx into an antenna system consisting of a 140 foot inverted L, 30 feet above ground with a buried ground radial 99 feet long. What is so unusual about that? Certainly not a venture of biblical proportions, IMO. Perhaps you haven't flipped enough of your calendar pages? RF |
jgboyles wrote Hi Reg, Interesting, but isn't a 30 metre wire more like 100 feet instead of 60 feet? According to the conversions on your programs it is. ============================= It's in the right ball park. I'm pleased you make use of the measurements conversions in some of my programs. Its just a small thing I can do to help paying back for what you Americans did by helping us poor Brits to win the war. ;o) ;o) ;o) ;o) ;o) ;o) ---- Reg. |
Reg:
Indeed, my grandfather fought with "you brits" during the war, he had many german lugars, swords, coins and memorabilia he brought back... He seen enough to hold a high respect for the british empires' citizens--for the rest of his life... indeed, his words inspired such in others... Unless he greatly exaggerated the acts of glory, valor, bravery and loyalty demonstrated by the british troops, (which I never found existed in my grandfather--exaggeration), which he shared foxholes with, you brits have nothing to repay... we are even--perhaps we even got the better of the deal, as our forefathers had the company of decent men to share those bad times with... he was there and liberated the Nazi camps, in the end... he would cry when he would describe what his eyes could never forget... .... he spoke highly of the aussies also, indeed, he commented, "some of those men were above mere human beings" (his EXACT words), when referring to both brits and aussies. I have told my son of this man (his great-grandfather) and the men he (my grandfather) was fortunate enough to have had at his side... If the future demands, let us hope we shall be such allies again... John "Reg Edwards" wrote in message ... jgboyles wrote Hi Reg, Interesting, but isn't a 30 metre wire more like 100 feet instead of 60 feet? According to the conversions on your programs it is. ============================= It's in the right ball park. I'm pleased you make use of the measurements conversions in some of my programs. Its just a small thing I can do to help paying back for what you Americans did by helping us poor Brits to win the war. ;o) ;o) ;o) ;o) ;o) ;o) ---- Reg. |
Reg Edwards wrote:
I'm pleased you make use of the measurements conversions in some of my programs. Its just a small thing I can do to help paying back for what you Americans did by helping us poor Brits to win the war. ;o) ;o) ;o) ;o) ;o) ;o) Hey Reg, guess where our English system of measurements came from. -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- |
On Thu, 28 Jul 2005 22:13:24 -0500, Cecil Moore
wrote: Hey Reg, guess where our English system of measurements came from. The Romans, the same as ours Rex. T |
Some of the lads here buried a wire (no counterpoise) in the
sand in the desert and successfully transmitted some thousands of miles to the disbelief of the receiving stations. No measurements of any scientific stuff like soil conductivity, but. :-) Cheers Murray vk4aok Reg Edwards wrote: Some years back I buried a 30 metre (60-feet) auminium wire one spade depth in my back garden. Wire was 1.5 mm in diameter. Soil resistivity about 100 ohm-metres. To scientists that's 10 milli-Siemens. The near end of the wire came up in the shack. That's under my kitchen sink. It's still there. Open-circuit at the far end. As a counterpoise, something essential to tune it against, I erected a wire in the form of an inverted-L. This was about 30 feet high and overall length about 140 feet. I chose this length because it fitted nicely into my back garden. The front garden is too short even for an underground antenna. On the 160m band I fed into it about 30 watts from a home-brew transceiver so I can't provide for the record a manufacturer's type and serial number. However I still have the transceiver which can be inspected. Despite a high local noise level of S-6 I was able to communicate up to 60 miles with mobile stations in broad daylight on SSB. After sunset I could easily communicate with most of Europe on CW. I think a record of these buried antenna experiments should be kept for posterity, alongside the famous biblical work of B,L & E. By the way, as you see, I did remember to measure soil resistivity. It was the first thing I did. What buried wire do you think I used to measure it? ---- Reg, G4FGQ |
Reg Edwards wrote: Some years back I buried a 30 metre (60-feet) auminium wire one spade depth in my back garden. Wire was 1.5 mm in diameter. Soil resistivity about 100 ohm-metres. To scientists that's 10 milli-Siemens. The near end of the wire came up in the shack. That's under my kitchen sink. It's still there. Open-circuit at the far end. Reg, was that 30 meters and 90 feet or 60 feet and 20 meters? Just for us mathematically challenged. W4ZCB |
Reg, was that 30 meters and 90 feet or 60 feet and 20 meters? Just
for us mathematically challenged. W4ZCB =================================== Harrold, To be exact, 30 meters = 98.43 feet. It was NOT a deliberate mistake to check on how much interest would be displayed in the experiment by readers. But it could have been. ;o) I did swap the connections between antenna and counterpoise and, as you can guess, it didn't make a scrap of difference. The underground antenna ended up in a bunch of other radials. But the best radial I have is the incoming domestic water main which is terminated at its other end by 100,000 miles of underground pipes feeding the whole of the Black Country (where it all began) and the Great City of Birmingham (which yesterday suffered a tornado due to Earth warming climatic changes caused by American pollution of the atmosphere). It was only the day before that life in the city was disrupted by police raids on houses alleged to be occupied by unsuccessful suicide bombers. Birmingham, in opposition to Manchester, will do anything to get into the news! ---- Reg. |
In message , Reg
Edwards writes Reg, was that 30 meters and 90 feet or 60 feet and 20 meters? Just for us mathematically challenged. W4ZCB =================================== Harrold, To be exact, 30 meters = 98.43 feet. It was NOT a deliberate mistake to check on how much interest would be displayed in the experiment by readers. But it could have been. ;o) I did swap the connections between antenna and counterpoise and, as you can guess, it didn't make a scrap of difference. The underground antenna ended up in a bunch of other radials. But the best radial I have is the incoming domestic water main which is terminated at its other end by 100,000 miles of underground pipes feeding the whole of the Black Country (where it all began) and the Great City of Birmingham (which yesterday suffered a tornado due to Earth warming climatic changes caused by American pollution of the atmosphere). It was only the day before that life in the city was disrupted by police raids on houses alleged to be occupied by unsuccessful suicide bombers. Birmingham, in opposition to Manchester, will do anything to get into the news! It has to. Mike |
I've used an antenna made of buried radial wires for many years, with a
vertical counterpoise, and AM broadcasters have been using this technique for the better part of a century. Works fine. Hm, maybe I should add another column to the wire specification table in EZNEC so people can specify whether the wire is an (A)ntenna or (C)ounterpoise. . . A related antenna was described many years ago in one of the amateur magazines. The author explained that when we construct a vertical antenna, an image antenna appears in the ground. So he simply dug a hole in the ground in put his vertical below ground. The image antenna did the radiating, of course. I did a pretty thorough search of QST and couldn't find the article -- I'd be indebted to anyone who can recall where this appeared. My guess is that it was around the early '60s. In an April issue of course. Roy Lewallen, W7EL Reg Edwards wrote: Some years back I buried a 30 metre (60-feet) auminium wire one spade depth in my back garden. Wire was 1.5 mm in diameter. Soil resistivity about 100 ohm-metres. To scientists that's 10 milli-Siemens. The near end of the wire came up in the shack. That's under my kitchen sink. It's still there. Open-circuit at the far end. As a counterpoise, something essential to tune it against, I erected a wire in the form of an inverted-L. This was about 30 feet high and overall length about 140 feet. I chose this length because it fitted nicely into my back garden. The front garden is too short even for an underground antenna. On the 160m band I fed into it about 30 watts from a home-brew transceiver so I can't provide for the record a manufacturer's type and serial number. However I still have the transceiver which can be inspected. Despite a high local noise level of S-6 I was able to communicate up to 60 miles with mobile stations in broad daylight on SSB. After sunset I could easily communicate with most of Europe on CW. I think a record of these buried antenna experiments should be kept for posterity, alongside the famous biblical work of B,L & E. By the way, as you see, I did remember to measure soil resistivity. It was the first thing I did. What buried wire do you think I used to measure it? ---- Reg, G4FGQ |
I agree that it was an April issue and I think my old friend W8DMR
(Bill) may have written it. However, I was thinking it more in the mid 60's. de W8CCW On Fri, 29 Jul 2005 12:51:56 -0700, Roy Lewallen wrote: I've used an antenna made of buried radial wires for many years, with a vertical counterpoise, and AM broadcasters have been using this technique for the better part of a century. Works fine. Hm, maybe I should add another column to the wire specification table in EZNEC so people can specify whether the wire is an (A)ntenna or (C)ounterpoise. . . A related antenna was described many years ago in one of the amateur magazines. The author explained that when we construct a vertical antenna, an image antenna appears in the ground. So he simply dug a hole in the ground in put his vertical below ground. The image antenna did the radiating, of course. I did a pretty thorough search of QST and couldn't find the article -- I'd be indebted to anyone who can recall where this appeared. My guess is that it was around the early '60s. In an April issue of course. Roy Lewallen, W7EL Reg Edwards wrote: Some years back I buried a 30 metre (60-feet) auminium wire one spade depth in my back garden. Wire was 1.5 mm in diameter. Soil resistivity about 100 ohm-metres. To scientists that's 10 milli-Siemens. The near end of the wire came up in the shack. That's under my kitchen sink. It's still there. Open-circuit at the far end. As a counterpoise, something essential to tune it against, I erected a wire in the form of an inverted-L. This was about 30 feet high and overall length about 140 feet. I chose this length because it fitted nicely into my back garden. The front garden is too short even for an underground antenna. On the 160m band I fed into it about 30 watts from a home-brew transceiver so I can't provide for the record a manufacturer's type and serial number. However I still have the transceiver which can be inspected. Despite a high local noise level of S-6 I was able to communicate up to 60 miles with mobile stations in broad daylight on SSB. After sunset I could easily communicate with most of Europe on CW. I think a record of these buried antenna experiments should be kept for posterity, alongside the famous biblical work of B,L & E. By the way, as you see, I did remember to measure soil resistivity. It was the first thing I did. What buried wire do you think I used to measure it? ---- Reg, G4FGQ |
Reg:
I can't even dream of burying a perfectly good, working, beautiful, sleek antenna! .... I shall refrain from burying any antenna, before its' time ... John "Reg Edwards" wrote in message ... Some years back I buried a 30 metre (60-feet) auminium wire one spade depth in my back garden. Wire was 1.5 mm in diameter. Soil resistivity about 100 ohm-metres. To scientists that's 10 milli-Siemens. The near end of the wire came up in the shack. That's under my kitchen sink. It's still there. Open-circuit at the far end. As a counterpoise, something essential to tune it against, I erected a wire in the form of an inverted-L. This was about 30 feet high and overall length about 140 feet. I chose this length because it fitted nicely into my back garden. The front garden is too short even for an underground antenna. On the 160m band I fed into it about 30 watts from a home-brew transceiver so I can't provide for the record a manufacturer's type and serial number. However I still have the transceiver which can be inspected. Despite a high local noise level of S-6 I was able to communicate up to 60 miles with mobile stations in broad daylight on SSB. After sunset I could easily communicate with most of Europe on CW. I think a record of these buried antenna experiments should be kept for posterity, alongside the famous biblical work of B,L & E. By the way, as you see, I did remember to measure soil resistivity. It was the first thing I did. What buried wire do you think I used to measure it? ---- Reg, G4FGQ |
My brother quit the power company when they were switching to "underground
utilities" - he got tired of burying those telephone poles so deep! And I had to give up chicken farming because the county extension agent said I was planting them too deep - I think I must have been planting them too near the underground power lines. "John Smith" wrote in message ... Reg: I can't even dream of burying a perfectly good, working, beautiful, sleek antenna! ... I shall refrain from burying any antenna, before its' time ... John |
Sometimes it works if you unplug it, turn the plug 180 degrees, and plug it
back in. ground loops get hairy sometimes. |
wrote:
Reg Edwards wrote: Some years back I buried a 30 metre (60-feet) auminium wire... Hi Reg, Interesting, but isn't a 30 metre wire more like 100 feet instead of 60 feet? ... Perhaps Reg took into account a velocity factor for sub-ground aluminum wire? Irv VE6BP :-) -- -------------------------------------- Diagnosed Type II Diabetes March 5 2001 Beating it with diet and exercise! 297/215/210 (to be revised lower) 58"/43"(!)/44" (already lower too!) -------------------------------------- Visit my HomePage at http://members.shaw.ca/finkirv/index.html Visit my Baby Sofia website at http://members.shaw.ca/finkirv4/index.htm Visit my OLDTIMERS website at http://members.shaw.ca/finkirv5/index.htm -------------------- Irv Finkleman, Grampa/Ex-Navy/Old Fart/Ham Radio VE6BP Calgary, Alberta, Canada |
Hal:
:| - confused, stiff upper lip I'll recover by the time of your next post. grin John "Hal Rosser" wrote in message ... My brother quit the power company when they were switching to "underground utilities" - he got tired of burying those telephone poles so deep! And I had to give up chicken farming because the county extension agent said I was planting them too deep - I think I must have been planting them too near the underground power lines. "John Smith" wrote in message ... Reg: I can't even dream of burying a perfectly good, working, beautiful, sleek antenna! ... I shall refrain from burying any antenna, before its' time ... John |
the Great City of Birmingham (which yesterday suffered a tornado due to Earth warming climatic changes caused by American pollution of the atmosphere). Birmingham, in opposition to Manchester, will do anything to get into the news! ---- Reg. Hi Reg, I live in the Great City of Birmingham, and there was no tornado yesterday due to Earth warming climatic changes caused by American pollution of the atmosphere. We do have tornados here from time to time and have even before the American pollution of the atmosphere. Of course I live in B'ham Alabama USA so I am closer to the pollution than you are. The company I work for has spent billions on environmental projects as has a number of other companies. It is starting to make a big difference in the air quality over here. I doubt seriously the B'ham tornado was anything out of the ordinary (1 every 100 years). If you want to see who is really cranking out the pollution, look at third world countries who are attempting to progress, which takes energy that they can not afford, much less any pollution control. China comes to mind. Gary N4AST |
This has been done since the beginning of radio. Nothing new. However, I am
interested in the sand antenna. I would love to hear more about working antennas that exist entirely below ground. I am guessing but would say this would not work on any band above 160 meters. I know the Navy has made huge underground radiators at frequencies like 50 khz. I would be surprised to hear that something as high as 1.8 mhz could be made to work. "Reg Edwards" wrote in message ... Some years back I buried a 30 metre (60-feet) auminium wire one spade depth in my back garden. Wire was 1.5 mm in diameter. Soil resistivity about 100 ohm-metres. To scientists that's 10 milli-Siemens. The near end of the wire came up in the shack. That's under my kitchen sink. It's still there. Open-circuit at the far end. As a counterpoise, something essential to tune it against, I erected a wire in the form of an inverted-L. This was about 30 feet high and overall length about 140 feet. I chose this length because it fitted nicely into my back garden. The front garden is too short even for an underground antenna. On the 160m band I fed into it about 30 watts from a home-brew transceiver so I can't provide for the record a manufacturer's type and serial number. However I still have the transceiver which can be inspected. Despite a high local noise level of S-6 I was able to communicate up to 60 miles with mobile stations in broad daylight on SSB. After sunset I could easily communicate with most of Europe on CW. I think a record of these buried antenna experiments should be kept for posterity, alongside the famous biblical work of B,L & E. By the way, as you see, I did remember to measure soil resistivity. It was the first thing I did. What buried wire do you think I used to measure it? ---- Reg, G4FGQ |
Michael wrote:
This has been done since the beginning of radio. Nothing new. However, I am interested in the sand antenna. I would love to hear more about working antennas that exist entirely below ground. I am guessing but would say this would not work on any band above 160 meters. I know the Navy has made huge underground radiators at frequencies like 50 khz. I would be surprised to hear that something as high as 1.8 mhz could be made to work. I recall reading some years ago about underground antenna experiments done by the military. I believe the were done well into the HF range. A trench was dug, the antenna put into the trench but not in direct contact with the soil, then the top was covered. The objective was to make a concealed antenna for relatively short range communication. The signals were much weaker than for an above-ground antenna (~30 dB if I recall correctly, but I might not), but still usable for the purpose at hand. This shouldn't be surprising. Roy Lewallen, W7EL |
You might be interested in the 1918 article on underground antennas.
http://www.rexresearch.com/rogers/1rogers.htm "Roy Lewallen" wrote in message ... Michael wrote: This has been done since the beginning of radio. Nothing new. However, I am interested in the sand antenna. I would love to hear more about working antennas that exist entirely below ground. I am guessing but would say this would not work on any band above 160 meters. I know the Navy has made huge underground radiators at frequencies like 50 khz. I would be surprised to hear that something as high as 1.8 mhz could be made to work. I recall reading some years ago about underground antenna experiments done by the military. I believe the were done well into the HF range. A trench was dug, the antenna put into the trench but not in direct contact with the soil, then the top was covered. The objective was to make a concealed antenna for relatively short range communication. The signals were much weaker than for an above-ground antenna (~30 dB if I recall correctly, but I might not), but still usable for the purpose at hand. This shouldn't be surprising. Roy Lewallen, W7EL |
Fred W4JLE wrote:
You might be interested in the 1918 article on underground antennas. http://www.rexresearch.com/rogers/1rogers.htm Thanks for the reference. A key observation from it is: "One of the Naval experts present mentioned that it had been found that the penetration of the ground wave component increases with an increase in wavelength. This is an important fact and helps to explain the operation of this new radio system, with its aerials buried in the ground." I believe this method is still being used for communications to submarines. It depends heavily on the very great skin depth and relatively low attenuation in sea water at the VLF wavelengths used. The buried antennas I was referring to operate, as far as I know, with normal field propagation through the air, not through the ground. Here are the skin depth in feet and attenuation per foot in salt water: Freq Skin Depth Atten ft dB per ft 10 MHz 0.23 37 1 MHz 0.73 12 100 kHz 2.3 3.7 10 kHz 7.4 1.2 1 kHz 23 0.37 100 Hz 74 0.12 And here they are for average ground: Freq Skin Depth Atten ft dB per ft 10 MHz 13 0.66 1 MHz 25 0.34 100 kHz 74 0.12 10 kHz 230 0.037 1 kHz 738 0.012 100 Hz 2300 0.0037 So communication through the ground or even salt water is practical at low frequencies. High frequency is another matter, though. But that doesn't preclude using buried antennas for sky wave propagation. Roy Lewallen, W7EL |
John Ferrell wrote:
I agree that it was an April issue and I think my old friend W8DMR (Bill) may have written it. However, I was thinking it more in the mid 60's. de W8CCW My guess as to the date could easily be that far off. But if your friend wrote it for QST or HR, he used a pseudonym -- I don't see his call or name in the inclusive indexes of either magazine. It must have been in CQ or 73. I can still recall the diagram, showing the buried antenna and the dotted "image" above ground. Roy Lewallen, W7EL |
He may have used a pseudonym. He did prefer to write for CQ, they paid
a little bit where QST did (does?) not. I have been out of touch with Bill since leaving the Central Ohio area. As I recall, after he had one such artical published he received quite a few letters from people who took it seriously. de W8CCW On Fri, 29 Jul 2005 21:20:08 -0700, Roy Lewallen wrote: John Ferrell wrote: I agree that it was an April issue and I think my old friend W8DMR (Bill) may have written it. However, I was thinking it more in the mid 60's. de W8CCW My guess as to the date could easily be that far off. But if your friend wrote it for QST or HR, he used a pseudonym -- I don't see his call or name in the inclusive indexes of either magazine. It must have been in CQ or 73. I can still recall the diagram, showing the buried antenna and the dotted "image" above ground. Roy Lewallen, W7EL |
That is great!
I will use that at the next Lios Club meeting and aso in my church newsletter... de W8CCW On Fri, 29 Jul 2005 18:01:11 -0400, "Hal Rosser" wrote: My brother quit the power company when they were switching to "underground utilities" - he got tired of burying those telephone poles so deep! And I had to give up chicken farming because the county extension agent said I was planting them too deep - I think I must have been planting them too near the underground power lines. "John Smith" wrote in message ... Reg: I can't even dream of burying a perfectly good, working, beautiful, sleek antenna! ... I shall refrain from burying any antenna, before its' time ... John |
Back in the day, we received traffic from the station in Jim Creek while
submerged. They used a 13 mile array strung between 2 mountains. IIRC it was on 18KC. CW only as any frequency shift would have put the finals out of resonance. Much better methods today that remain classified. I know we could receive it when submerged in the Red Sea. "Roy Lewallen" wrote in message ... I believe this method is still being used for communications to submarines. It depends heavily on the very great skin depth and relatively low attenuation in sea water at the VLF wavelengths used. The buried antennas I was referring to operate, as far as I know, with normal field propagation through the air, not through the ground. So communication through the ground or even salt water is practical at low frequencies. High frequency is another matter, though. But that doesn't preclude using buried antennas for sky wave propagation. Roy Lewallen, W7EL |
"Fred W4JLE" wrote in message ... Back in the day, we received traffic from the station in Jim Creek while submerged. They used a 13 mile array strung between 2 mountains. IIRC it was on 18KC. CW only as any frequency shift would have put the finals out of resonance. Much better methods today that remain classified. I know we could receive it when submerged in the Red Sea. "Roy Lewallen" wrote in message ... I believe this method is still being used for communications to submarines. It depends heavily on the very great skin depth and relatively low attenuation in sea water at the VLF wavelengths used. The buried antennas I was referring to operate, as far as I know, with normal field propagation through the air, not through the ground. So communication through the ground or even salt water is practical at low frequencies. High frequency is another matter, though. But that doesn't preclude using buried antennas for sky wave propagation. Roy Lewallen, W7EL Did the Navy ever deploy the Long-Range Autonomous Homing Bottle? -- Ed WB6WSN El Cajon, CA USA |
Roy. as you know, radio propagation through the ground follows exactly
the same laws as propagation through anything else. All is governed by the resistivity, permeability and permittivity of the medium, at a partcular frequency, and the geometry of the interfaces between different mediums. The problem of finding solutions to paricular problems lies only in entering input data into a general purpose, number crunching computer program, which I'm sure versions of it already exist. |
Reg Edwards wrote:
Roy. as you know, radio propagation through the ground follows exactly the same laws as propagation through anything else. Sure. The only real differences among salt water, dirt, and air are the loss -- which is a big difference -- and propagation velocity. All is governed by the resistivity, permeability and permittivity of the medium, at a partcular frequency, and the geometry of the interfaces between different mediums. The problem of finding solutions to paricular problems lies only in entering input data into a general purpose, number crunching computer program, which I'm sure versions of it already exist. NEC-4 can handle antennas and propagation in two media of infinite extent separated by an infinite plane boundary. Neither one has to be air. While this doesn't imitate some real situations very well, it can produce some good insights into propagation and the performance of antennas embedded in a medium other than air. Roy Lewallen, W7EL |
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