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#11
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Galvanized or Copper Gound Rods?
On May 30, 5:00*pm, You wrote:
In article , *Robert Smits wrote: Richard Clark wrote: On Thu, 27 May 2010 17:36:41 -0700, Bob Smits wrote: Is there a significant difference between using the galvanized steel ground rods and copper to create an rf gound? Hi Bob, Two answers for that: 1. *No difference whatever; B. *Neither make an RF ground. Updates will follow this brief announcement. 73's Richard Clark, KB7QHC Looks like my follow up post didn't make it through. Richard I intend these three ground rods to be the start of grounding my station, not as a counterpoise for one of my antennas. These will be bonded to my radios and the electrical service entrance ground. Why do you say this does not make an RF ground? Thanks, Bob A lot of folks, make the same mistake, in thinking that Electrical Ground and RF Ground are the same thing. They, clearly, are NOT, the same thing or even close to the same thing, unless you happen to be living on a Salt Marsh. Ground Rods, of any kind, are only Electrical Grounds. Rf Grounding is a Totally Different bag of cats. RF Grounds need to be engineered, by someone who is familiar with Antenna Design and Installation Procedures, for the particular Antenna and landscape, where the antenna is to be installed. define "rf ground". |
#12
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Galvanized or Copper Gound Rods?
"K1TTT" wrote in message ... On May 30, 5:00 pm, You wrote: In article , Robert Smits wrote: Richard Clark wrote: On Thu, 27 May 2010 17:36:41 -0700, Bob Smits wrote: Is there a significant difference between using the galvanized steel ground rods and copper to create an rf gound? Hi Bob, Two answers for that: 1. No difference whatever; B. Neither make an RF ground. Updates will follow this brief announcement. 73's Richard Clark, KB7QHC Looks like my follow up post didn't make it through. Richard I intend these three ground rods to be the start of grounding my station, not as a counterpoise for one of my antennas. These will be bonded to my radios and the electrical service entrance ground. Why do you say this does not make an RF ground? Thanks, Bob A lot of folks, make the same mistake, in thinking that Electrical Ground and RF Ground are the same thing. They, clearly, are NOT, the same thing or even close to the same thing, unless you happen to be living on a Salt Marsh. Ground Rods, of any kind, are only Electrical Grounds. Rf Grounding is a Totally Different bag of cats. RF Grounds need to be engineered, by someone who is familiar with Antenna Design and Installation Procedures, for the particular Antenna and landscape, where the antenna is to be installed. define "rf ground". Something that provides a counterpoise for an unbalanced feedline situation that doesn't result in RF energy being wasted to heat earthworms, soil, etc. and radiates RF energy efficiently. |
#13
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Galvanized or Copper Gound Rods?
On Jun 20, 3:14*pm, "Pete Bertini" wrote:
"K1TTT" wrote in message ... On May 30, 5:00 pm, You wrote: In article , Robert Smits wrote: Richard Clark wrote: On Thu, 27 May 2010 17:36:41 -0700, Bob Smits wrote: Is there a significant difference between using the galvanized steel ground rods and copper to create an rf gound? Hi Bob, Two answers for that: 1. No difference whatever; B. Neither make an RF ground. Updates will follow this brief announcement. 73's Richard Clark, KB7QHC Looks like my follow up post didn't make it through. Richard I intend these three ground rods to be the start of grounding my station, not as a counterpoise for one of my antennas. These will be bonded to my radios and the electrical service entrance ground. Why do you say this does not make an RF ground? Thanks, Bob A lot of folks, make the same mistake, in thinking that Electrical Ground and RF Ground are the same thing. They, clearly, are NOT, the same thing or even close to the same thing, unless you happen to be living on a Salt Marsh. Ground Rods, of any kind, are only Electrical Grounds. Rf Grounding is a Totally Different bag of cats. RF Grounds need to be engineered, by someone who is familiar with Antenna Design and Installation Procedures, for the particular Antenna and landscape, where the antenna is to be installed. define "rf ground". Something that provides a counterpoise for an unbalanced feedline situation that doesn't result in RF energy being wasted to heat earthworms, soil, etc. and radiates RF energy efficiently. the ground radiates? that's interesting. so the raised radials on my 80m 4-square would be considered an rf ground? |
#14
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Galvanized or Copper Gound Rods?
"K1TTT" wrote in message ... On Jun 20, 3:14 pm, "Pete Bertini" wrote: "K1TTT" wrote in message ... On May 30, 5:00 pm, You wrote: In article , Robert Smits wrote: Richard Clark wrote: On Thu, 27 May 2010 17:36:41 -0700, Bob Smits wrote: Is there a significant difference between using the galvanized steel ground rods and copper to create an rf gound? Hi Bob, Two answers for that: 1. No difference whatever; B. Neither make an RF ground. Updates will follow this brief announcement. 73's Richard Clark, KB7QHC Looks like my follow up post didn't make it through. Richard I intend these three ground rods to be the start of grounding my station, not as a counterpoise for one of my antennas. These will be bonded to my radios and the electrical service entrance ground. Why do you say this does not make an RF ground? Thanks, Bob A lot of folks, make the same mistake, in thinking that Electrical Ground and RF Ground are the same thing. They, clearly, are NOT, the same thing or even close to the same thing, unless you happen to be living on a Salt Marsh. Ground Rods, of any kind, are only Electrical Grounds. Rf Grounding is a Totally Different bag of cats. RF Grounds need to be engineered, by someone who is familiar with Antenna Design and Installation Procedures, for the particular Antenna and landscape, where the antenna is to be installed. define "rf ground". Something that provides a counterpoise for an unbalanced feedline situation that doesn't result in RF energy being wasted to heat earthworms, soil, etc. and radiates RF energy efficiently. the ground radiates? that's interesting. so the raised radials on my 80m 4-square would be considered an rf ground? I would consider them to be an effective RF ground at their 1/4 wave resonant points, just as would a tuned artificial RF ground used for stations at elevated locations. Pete |
#15
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Galvanized or Copper Gound Rods?
K1TTT wrote:
On Jun 20, 3:14 pm, "Pete Bertini" wrote: "K1TTT" wrote in message ... On May 30, 5:00 pm, You wrote: In article , Robert Smits wrote: Richard Clark wrote: On Thu, 27 May 2010 17:36:41 -0700, Bob Smits wrote: Is there a significant difference between using the galvanized steel ground rods and copper to create an rf gound? Hi Bob, Two answers for that: 1. No difference whatever; B. Neither make an RF ground. Updates will follow this brief announcement. 73's Richard Clark, KB7QHC Looks like my follow up post didn't make it through. Richard I intend these three ground rods to be the start of grounding my station, not as a counterpoise for one of my antennas. These will be bonded to my radios and the electrical service entrance ground. Why do you say this does not make an RF ground? Thanks, Bob A lot of folks, make the same mistake, in thinking that Electrical Ground and RF Ground are the same thing. They, clearly, are NOT, the same thing or even close to the same thing, unless you happen to be living on a Salt Marsh. Ground Rods, of any kind, are only Electrical Grounds. Rf Grounding is a Totally Different bag of cats. RF Grounds need to be engineered, by someone who is familiar with Antenna Design and Installation Procedures, for the particular Antenna and landscape, where the antenna is to be installed. define "rf ground". Something that provides a counterpoise for an unbalanced feedline situation that doesn't result in RF energy being wasted to heat earthworms, soil, etc. and radiates RF energy efficiently. the ground radiates? that's interesting. so the raised radials on my 80m 4-square would be considered an rf ground? We should define "ground" while we're at it. - 73 de Mike N3LI - |
#16
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Galvanized or Copper Gound Rods?
"Michael Coslo" wrote ... We should define "ground" while we're at it. If antenna emits electrons (longitudinal Tesla waves) than the ground is the source of them. The lovers of the TEM will write more. S* |
#17
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Galvanized or Copper Gound Rods?
On Jun 21, 5:24*pm, "Szczepan Bialek" wrote:
"Michael Coslo" ... We should define "ground" while we're at it. If antenna emits electrons (longitudinal Tesla waves) than the ground is the source of them. The lovers of the TEM will write more. S* no one loves them more than you, so spew away if you wish. |
#18
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Galvanized or Copper Gound Rods?
In article ,
"Pete Bertini" wrote: define "rf ground". Something that provides a counterpoise for an unbalanced feedline situation that doesn't result in RF energy being wasted to heat earthworms, soil, etc. and radiates RF energy efficiently. the ground radiates? that's interesting. so the raised radials on my 80m 4-square would be considered an rf ground? I would consider them to be an effective RF ground at their 1/4 wave resonant points, just as would a tuned artificial RF ground used for stations at elevated locations. Pete Actually, a "GOOD" RF Ground will exhibit a very LOW Impedance across a broad Frequency Spectrum, and NOT just at any single Frequency.... When designing an RF Grounding System for a particular Site/Antenna System, it is almost as important to know the Frequencies, and Bandwidths, to be transmitted on, as it is to know the practical design of the Antenna itself. Earth Conductivity has a much smaller effect than most folks think. |
#19
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Galvanized or Copper Gound Rods?
"You" wrote in message ... In article , "Pete Bertini" wrote: define "rf ground". Something that provides a counterpoise for an unbalanced feedline situation that doesn't result in RF energy being wasted to heat earthworms, soil, etc. and radiates RF energy efficiently. the ground radiates? that's interesting. so the raised radials on my 80m 4-square would be considered an rf ground? I would consider them to be an effective RF ground at their 1/4 wave resonant points, just as would a tuned artificial RF ground used for stations at elevated locations. Pete Actually, a "GOOD" RF Ground will exhibit a very LOW Impedance across a broad Frequency Spectrum, and NOT just at any single Frequency.... When designing an RF Grounding System for a particular Site/Antenna System, it is almost as important to know the Frequencies, and Bandwidths, to be transmitted on, as it is to know the practical design of the Antenna itself. Earth Conductivity has a much smaller effect than most folks think. Oh dear. What does this say about "Artificial RF Grounds?" For that matter, is a tuned "artificial RF ground" a real "ground" or part of the antenna's radiation system? Pete |
#20
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Galvanized or Copper Gound Rods?
On Jun 21, 10:30*pm, "Pete Bertini" wrote:
"You" wrote in message ... In article , "Pete Bertini" wrote: define "rf ground". Something that provides a counterpoise for an unbalanced feedline situation that doesn't result in RF energy being wasted to heat earthworms, soil, etc. and radiates RF energy efficiently. the ground radiates? *that's interesting. so the raised radials on my 80m 4-square would be considered an rf ground? I would consider them to be an effective RF ground at their 1/4 wave resonant points, just as would a tuned artificial RF ground used for stations at elevated locations. Pete Actually, a "GOOD" RF Ground will exhibit a very LOW Impedance across a broad Frequency Spectrum, and NOT just at any single Frequency.... When designing an RF Grounding System for a particular Site/Antenna System, it is almost as important to know the Frequencies, and Bandwidths, to be transmitted on, as it is to know the practical design of the Antenna itself. Earth Conductivity has a much smaller effect than most folks think. Oh dear. What does this say about "Artificial RF Grounds?" For that matter, is a tuned "artificial RF ground" a real *"ground" or part of the antenna's radiation system? Pete its part of the 'system' but radiating or not can be debated. There are a couple problems when talking about RF Grounds. You can not equalize the rf voltage over anything that is an appreciable fraction of a wavelength using any type or combination of rods, radials, screens, or rings... it just ain't possible. any ground system other than the fictional 'perfect' ground will have a pattern of voltage peaks and nulls much like standing waves in 2 or 3 dimensions. therefor you can not call any particular point on the ground system 'ground' for purposes of voltage measurements... nor can you trust any particular point to be equal to any other point, so you can get rf burns while standing on a 'ground' screen and touching a coax shield or neutral or 'ground' power cable. The whole purpose of the 'artificial' ground is to force one of the voltage nulls to be where it will do the most good... if that means you have problems with rf getting into your computer keyboard, or get burnt by the mic when you swallow it, you can 'tune' the ground to cancel out that effect locally... of course that means that there will be changes in other places that may cause other problems, but at least you won't get burned. Now, on to the 'rf ground' as it applies to something you build under a vertical radiator.... sorry, this will have to wait... just sleep on currents going up the vertical having to be equal and opposite all the currents flowing back into the shield side of the coax... no matter where they come from, and imagine all the chances for currents to be where you don't want them. |
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