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#1
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"gb" wrote in message ... "Dave Platt" wrote in message ... In article , Rob Collis wrote: Hi Joe, IMHO it is best to isolate the ground used in the shack from the household ground. This should reduce noise from any mains supplied appliances. You could use a third rod for the antenna no problem. In the United States, most localities incorporate the National Electric Code into their own local building codes. It is my understanding that the NEC requires that each building structure have precisely one "ground system", and that this requires that all ground rods be reliably "bonded" together (typically via 6-gauge-or-heavier wire). The ground-system bonding is required in order to reduce the degree to which ground-voltage differentials can occur in the case of an electrical fault or nearby lighting strike. The bonding reduces the current that can flow through appliances that are connected to two or more independent "ground" systems (e.g. a building's main electrical ground, and a separate ground stake near an antenna). Putting in a second ground rod near the hamshack can be a good idea, as it reduces the length of the ground wire from rig to ground rod and can improve the quality of the RF ground (depends a lot on wire length and frequency). However, in order to comply with the NEC, this ground rod must be bonded to the main building ground. I don't know what the rules are in other countries. -- Dave Platt, AE6EO Dave is correct about NEC requires, HOWEVER please check with you local municipal (or country/parish) building department (or code enforcement) - there are variations that are more restrictive than NEC in SOME U.S. localities. That said, IF you are going to have a tower or large antenna array - RF grounding needs to be addressed separately from electrical service grounding. This area also has different requirements in SOME areas (for example - parts of Florida have the highest lightning hits per year). Glen Zook, K9STH has given talks and presentations on this subject - this information can be found he http://home.comcast.net/~k9sth/ w9gb Please, PLEASE, disregard every bit of that RUBBISH about "dissipation" (prevention) of lightning strikes in K9STH's website. There is not one single piece of scientific evidence to any of that bullcrap. The theories of Charge-transfer-systems (CTS), Early Steamer Emissions (ESE) or ANY kind of lightning prevention are total malarkey. The cost of gathering international review and wide publication of DIScrediting these phony's is incredible, but the IEEE has done so over and over again. There was good advice in this thread (and one bad one, advising isolation of house and radio grounds), until "gb" dragged that old nuttiness about dissipators out of the closet. Best regards, Jack Painter Virginia Beach, Virginia |
#2
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If I understand correctly the just of these replies, -- I would be better
off if I installed a so-called "stand-alone" ground rod that was several feet a way from the ground rod that my home was on and use this "stand-alone" ground rod solely for my shack equipment, and then driving another ground rod by my Butternut vertical and connecting it to the antenna ground rod. Am I correct in this? What is confusing to me is what one of the replies suggested that the rods be bonded or connected together. If that is a correct thing to do I don't see what the difference would be to using a single ground rod. After-all a ground rod is a ground rod. Thanks again for all your help. 73's " wrote in message news:zHhae.4351$lz1.2472@lakeread01... "gb" wrote in message ... "Dave Platt" wrote in message ... In article , Rob Collis wrote: Hi Joe, IMHO it is best to isolate the ground used in the shack from the household ground. This should reduce noise from any mains supplied appliances. You could use a third rod for the antenna no problem. In the United States, most localities incorporate the National Electric Code into their own local building codes. It is my understanding that the NEC requires that each building structure have precisely one "ground system", and that this requires that all ground rods be reliably "bonded" together (typically via 6-gauge-or-heavier wire). The ground-system bonding is required in order to reduce the degree to which ground-voltage differentials can occur in the case of an electrical fault or nearby lighting strike. The bonding reduces the current that can flow through appliances that are connected to two or more independent "ground" systems (e.g. a building's main electrical ground, and a separate ground stake near an antenna). Putting in a second ground rod near the hamshack can be a good idea, as it reduces the length of the ground wire from rig to ground rod and can improve the quality of the RF ground (depends a lot on wire length and frequency). However, in order to comply with the NEC, this ground rod must be bonded to the main building ground. I don't know what the rules are in other countries. -- Dave Platt, AE6EO Dave is correct about NEC requires, HOWEVER please check with you local municipal (or country/parish) building department (or code enforcement) - there are variations that are more restrictive than NEC in SOME U.S. localities. That said, IF you are going to have a tower or large antenna array - RF grounding needs to be addressed separately from electrical service grounding. This area also has different requirements in SOME areas (for example - parts of Florida have the highest lightning hits per year). Glen Zook, K9STH has given talks and presentations on this subject - this information can be found he http://home.comcast.net/~k9sth/ w9gb Please, PLEASE, disregard every bit of that RUBBISH about "dissipation" (prevention) of lightning strikes in K9STH's website. There is not one single piece of scientific evidence to any of that bullcrap. The theories of Charge-transfer-systems (CTS), Early Steamer Emissions (ESE) or ANY kind of lightning prevention are total malarkey. The cost of gathering international review and wide publication of DIScrediting these phony's is incredible, but the IEEE has done so over and over again. There was good advice in this thread (and one bad one, advising isolation of house and radio grounds), until "gb" dragged that old nuttiness about dissipators out of the closet. Best regards, Jack Painter Virginia Beach, Virginia |
#3
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Joe,
I didn't just suggest that the grounds be bonded (connected electrically), the NEC requires it. Placing a ground near your antenna base and near your shack will provide a path from your equipment to the ground that is less than a quarter-wave at 30 mHz. This will help keep the ground wire from radiating. If you do not comply with the NEC sec. 250 requirement, your insurance carrier has a case for not paying your claim. Multiple ground rods lower the impedence to earth in case of a lightning strike. Lightning is largely RF and will "prefer" a low impedence to earth. Bond the grounds together with #6 or larger wire. Don't take my word for it, ask your insurace company. I am a former Telco employee and grounding there is a religion, and not a minor one. See the BSPs ("Bell System Practices", now "Best Suggested Practices") and the web site of the Erico corporation. A. J. Surtees is one of THE authorities on grounding. Russ On Sat, 23 Apr 2005 02:04:29 GMT, "Joe" wrote: If I understand correctly the just of these replies, -- I would be better off if I installed a so-called "stand-alone" ground rod that was several feet a way from the ground rod that my home was on and use this "stand-alone" ground rod solely for my shack equipment, and then driving another ground rod by my Butternut vertical and connecting it to the antenna ground rod. Am I correct in this? What is confusing to me is what one of the replies suggested that the rods be bonded or connected together. If that is a correct thing to do I don't see what the difference would be to using a single ground rod. After-all a ground rod is a ground rod. Thanks again for all your help. 73's " wrote in message news:zHhae.4351$lz1.2472@lakeread01... "gb" wrote in message ... "Dave Platt" wrote in message ... In article , Rob Collis wrote: Hi Joe, IMHO it is best to isolate the ground used in the shack from the household ground. This should reduce noise from any mains supplied appliances. You could use a third rod for the antenna no problem. In the United States, most localities incorporate the National Electric Code into their own local building codes. It is my understanding that the NEC requires that each building structure have precisely one "ground system", and that this requires that all ground rods be reliably "bonded" together (typically via 6-gauge-or-heavier wire). The ground-system bonding is required in order to reduce the degree to which ground-voltage differentials can occur in the case of an electrical fault or nearby lighting strike. The bonding reduces the current that can flow through appliances that are connected to two or more independent "ground" systems (e.g. a building's main electrical ground, and a separate ground stake near an antenna). Putting in a second ground rod near the hamshack can be a good idea, as it reduces the length of the ground wire from rig to ground rod and can improve the quality of the RF ground (depends a lot on wire length and frequency). However, in order to comply with the NEC, this ground rod must be bonded to the main building ground. I don't know what the rules are in other countries. -- Dave Platt, AE6EO Dave is correct about NEC requires, HOWEVER please check with you local municipal (or country/parish) building department (or code enforcement) - there are variations that are more restrictive than NEC in SOME U.S. localities. That said, IF you are going to have a tower or large antenna array - RF grounding needs to be addressed separately from electrical service grounding. This area also has different requirements in SOME areas (for example - parts of Florida have the highest lightning hits per year). Glen Zook, K9STH has given talks and presentations on this subject - this information can be found he http://home.comcast.net/~k9sth/ w9gb Please, PLEASE, disregard every bit of that RUBBISH about "dissipation" (prevention) of lightning strikes in K9STH's website. There is not one single piece of scientific evidence to any of that bullcrap. The theories of Charge-transfer-systems (CTS), Early Steamer Emissions (ESE) or ANY kind of lightning prevention are total malarkey. The cost of gathering international review and wide publication of DIScrediting these phony's is incredible, but the IEEE has done so over and over again. There was good advice in this thread (and one bad one, advising isolation of house and radio grounds), until "gb" dragged that old nuttiness about dissipators out of the closet. Best regards, Jack Painter Virginia Beach, Virginia |
#4
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"Joe" wrote If I understand correctly the just of these replies, -- I'm afraid you still didn't get the gist, Joe... We could start over: 1.You want to set up shop in a basement. 2. You will have a Butternut vertical antenna nearby. 3. You want to know what should be grounded, and specifically where. 4. You asked about a bus-bar ground panel behind your radios. We don't know where your main house AC power panel is, or what kind of ground system it uses (could be the home's cold water supply pipe, a buried copper plate, or buried copper ground rod). This will be important later, and as others said, it is generally accepted practice and code in most countries to require that all systems use either one single grounding point, or bond any supplemental ground points to it. You should do at least some basic research on your own about grounding and bonding, if this is not abundantly clear to you. Your vertical may or may not require the use of RF radials, counterpoise, etc. Consult the manufacturers recommendations there, and follow them exactly. If you do use a radial system or buried copper wires, some common point of that system must bond to both the home's AC service ground point *and* the radio equipment's ground rod, if separate ones are used. What you do with your antenna and radio ground rods are entirely up to you. Electrical codes do not cover bonding RF grounds and an separate radio ground rod to each other. But a hundred years of sound lightning protection science *does* require that you always bond ALL ground systems together, NEVER leaving them isolated from each other. It gets very expensive to provide high voltage isolation transformers capable of safely isolating neutrals and ground systems, and while possible this is never a goal of the hobbyist. Bonding everything should be your goal in maintaining the basic forms of lightning protection. Next, you can consider AC surge protection at both the AC entrance and radio equipment. This is the protection from surge voltages that nearby lightning imposes on either the incoming power lines, or magnetically onto the house wiring. Included in the category of surge protection are Surge Protection Devices (most still call these lightning arrestors) that install in-line on your coaxial or open-wire feedlines. These SPD's limit the amount of damaging voltage presented to your radio's receiver circuitry. Coax shield grounding (braid of the coax connected to ground rods at several points as required) is what keeps damaging voltages off the exterior of the radios, including your fingers, and limits back-flow of destructive current out the back of the radios and into your homes AC wiring. The critical bonding of radio and shield-grounding rods to the homes AC entrance ground is of major importance here also. If you do not provide a very low impedance path around your equipment, surge voltages can force one through your equipment. A copper bus-bar or other wide low-impedance "collector" of single point grounding and bond points of all radios can be centered behind your equipment as you asked. But avoid daisy chaining radios in a series to bond them. As inconvenient and hard to conceal as it may be, individual bonding connections from each radio, straight to the single point ground (for the radio shack) is important. This not only provides the only approved bonding method for lightning protection, but limits ground-loop noise between equipments. Hope this helps tie some of the other good posters comments together. It's a long read, but I tried to cover most of the points of a total lightning protection system in this website. It might clear up how important the bonding is, I hope! http://members.cox.net/pc-usa/station/ground0.htm Best regards, Jack Painter Virginia Beach, Virginia |
#5
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On Sat, 23 Apr 2005 00:10:41 -0400, "Jack Painter"
wrote: "Joe" wrote If I understand correctly the just of these replies, -- I'm afraid you still didn't get the gist, Joe... We could start over: 1.You want to set up shop in a basement. 2. You will have a Butternut vertical antenna nearby. 3. You want to know what should be grounded, and specifically where. 4. You asked about a bus-bar ground panel behind your radios. *** BIG SNIP *** It's a long read, but I tried to cover most of the points of a total lightning protection system in this website. It might clear up how important the bonding is, I hope! http://members.cox.net/pc-usa/station/ground0.htm Best regards, Jack Painter Virginia Beach, Virginia Thanks Jack. You did tie (pun) it all together. Russ |
#6
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"Jack Painter" wrote in message
news:zHhae.4351$lz1.2472@lakeread01... "gb" wrote in message ... "Dave Platt" wrote in message ... In article , Rob Collis wrote: Hi Joe, IMHO it is best to isolate the ground used in the shack from the household ground. This should reduce noise from any mains supplied appliances. You could use a third rod for the antenna no problem. In the United States, most localities incorporate the National Electric Code into their own local building codes. It is my understanding that the NEC requires that each building structure have precisely one "ground system", and that this requires that all ground rods be reliably "bonded" together (typically via 6-gauge-or-heavier wire). The ground-system bonding is required in order to reduce the degree to which ground-voltage differentials can occur in the case of an electrical fault or nearby lighting strike. The bonding reduces the current that can flow through appliances that are connected to two or more independent "ground" systems (e.g. a building's main electrical ground, and a separate ground stake near an antenna). Putting in a second ground rod near the hamshack can be a good idea, as it reduces the length of the ground wire from rig to ground rod and can improve the quality of the RF ground (depends a lot on wire length and frequency). However, in order to comply with the NEC, this ground rod must be bonded to the main building ground. I don't know what the rules are in other countries. -- Dave Platt, AE6EO Dave is correct about NEC requires, HOWEVER please check with you local municipal (or country/parish) building department (or code enforcement) - there are variations that are more restrictive than NEC in SOME U.S. localities. That said, IF you are going to have a tower or large antenna array - RF grounding needs to be addressed separately from electrical service grounding. This area also has different requirements in SOME areas (for example - parts of Florida have the highest lightning hits per year). Glen Zook, K9STH has given talks and presentations on this subject - this information can be found he http://home.comcast.net/~k9sth/ w9gb Please, PLEASE, disregard every bit of that RUBBISH about "dissipation" (prevention) of lightning strikes in K9STH's website. There is not one single piece of scientific evidence to any of that bullcrap. The theories of Charge-transfer-systems (CTS), Early Steamer Emissions (ESE) or ANY kind of lightning prevention are total malarkey. The cost of gathering international review and wide publication of DIScrediting these phony's is incredible, but the IEEE has done so over and over again. There was good advice in this thread (and one bad one, advising isolation of house and radio grounds), until "gb" dragged that old nuttiness about dissipators out of the closet. Best regards, Jack Painter Virginia Beach, Virginia " but the IEEE has done so over and over again". ------- As a member of IEEE, ... my esteemed association strongly supported BPL .. which I consider a rubbish, politically motivated usage of network technology. Their creditability is suspect moving forward. As for NEC -- Chicago area standards which are stricter - and will not permit some lower requirements under the NEC. As for what is important at the end of the day - I have found that unless the insurer for the property and equipment agrees with the installation (and design) -- they won't pay for damage - no matter what was followed ! Although single point grounding should be used (as Jack points out) - over the past 30 years I have seen so many "in the field" violations of that principal (telephone, power, cable, broadcasting companies) -- and I am not the policeman for these installations or their engineering arguments - why they were installed that way. |
#7
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I agree that you should at the very least take K9STH's advice regarding
lightning with a grain of salt. There is some good advice about grounding, but there is also some bad advice, and most of his theories about lightning have been replaced in the last 20 years among the scientific community. Also, the way I see it, we ground our gear for low noise and good radiated signals. NEC grounds things for safety and lightning protection. What constitutes a "good" ground system may differ according to which viewpoint you adopt. |
#8
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On 23 Apr 2005 07:53:03 -0700, "
wrote: I agree that you should at the very least take K9STH's advice regarding lightning with a grain of salt. There is some good advice about grounding, but there is also some bad advice, and most of his theories about lightning have been replaced in the last 20 years among the scientific community. Is there a good layman's book on grounding amateur gear? Ask 10 hams a grounding question and you get 11 answers :-) bob k5qwg Also, the way I see it, we ground our gear for low noise and good radiated signals. NEC grounds things for safety and lightning protection. What constitutes a "good" ground system may differ according to which viewpoint you adopt. |
#9
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"Bob Miller" wrote Is there a good layman's book on grounding amateur gear? Ask 10 hams a grounding question and you get 11 answers :-) bob k5qwg Bob, it gets even worse when total lightning protection systems are involved. This book below (Grounding v. Bonding) is an excellent fundamental approach to the interrelationship between the two. Add to it the $35 NFPA-780 (Oct 2004 is current edition) Standard for Installation of Lightning Protection Systems, and you will be a long way toward understanding how to best protect equipment in your individual circumstances. http://www.mikeholt.com/bookcategory...&from=Products Best regards, Jack |
#10
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On Sat, 23 Apr 2005 19:31:18 GMT, Bob Miller
wrote: On 23 Apr 2005 07:53:03 -0700, " wrote: I agree that you should at the very least take K9STH's advice regarding lightning with a grain of salt. There is some good advice about grounding, but there is also some bad advice, and most of his theories about lightning have been replaced in the last 20 years among the scientific community. Is there a good layman's book on grounding amateur gear? Ask 10 hams a grounding question and you get 11 answers :-) bob k5qwg Also, the way I see it, we ground our gear for low noise and good radiated signals. NEC grounds things for safety and lightning protection. What constitutes a "good" ground system may differ according to which viewpoint you adopt. Yes, got to the library and copy sections 250 and 800 of the National Electric Code (NEC). It is quite clear and if you have passed element two you should be able to understand the language. I'll repeat myself because it bears repeating. All grounds are to be bonded together with at least #6 wire and mechanical connections (no soldering). Russ |
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