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Grounding for Gable end bracket & mast.
On Wed, 28 Jul 2010 18:59:16 -0500, tom wrote:
I think I see where you're going with this Richard, but you must realize by now that you're talking to a rock. To put it another way, he wouldn't pass the Turing Test. Actually, I am testing the chinese room argument. The operator's manual appears to be missing some pages. 73's Richard Clark, KB7QHC |
Grounding for Gable end bracket & mast.
On 7/28/2010 7:45 PM, Richard Clark wrote:
On Wed, 28 Jul 2010 18:59:16 -0500, wrote: I think I see where you're going with this Richard, but you must realize by now that you're talking to a rock. To put it another way, he wouldn't pass the Turing Test. Actually, I am testing the chinese room argument. The operator's manual appears to be missing some pages. 73's Richard Clark, KB7QHC Interesting, thanks. That is similar to some of the new systems that let you store encrypted data and perform operations on them without decrypting them or knowing what you've done. tom K0TAR |
Grounding for Gable end bracket & mast.
On Fri, 16 Jul 2010 08:45:12 -0400, John Ferrell
wrote: On Fri, 16 Jul 2010 02:37:18 -0400, Roger wrote: On Tue, 13 Jul 2010 10:52:14 -0400, John Ferrell wrote: I don't remember the sources but I have concluded that the Grounding wire should be no smaller than #6. #6 is a minimum required by code here in the Midland MI area. As it's a minimum, I would not use anything less than #2 Copper. More than 8 feet of ground rod is of little consequence. That depends on your soil conditions. Here I'd probably agree as the soil is usually quite moist and just a couple feet down is just plain wet. However a string of ground rods tied together can be quite effective. All ground rods should be tied together. Don't put your house between two electrodes! I'd put a circle of them around the house, all tied together every 16', but due to the garage and driveway, that is not possible. The ground rods are better directly under the structure that they are protecting. I have a 100' 45G 10' from the NW corner of the garage. Tied into it is a grounding system consisting of 32 or 33 8' ground rods connected together with over 600 feet of bare #2. This system consists of a ground rod about a foot outside the concrete bare in like with each tower leg. The cable is clamped to each tower leg and comes off in a curve to the ground rod and is extended out in a straight line at least 80' with additional ground rods every 16' (give or take a tad) This system also ties into the house electrical ground. There is an additional run that goes directly from the ground rod at the base of the 45G to the 25G on the West end of the shop. From there it goes on around the shop to the mast holding the 144/440 vertical and around the south side to enter the shop to provide grounding for the station and computers. This also ties the shop ground (which is on a different electrical feed) to the house ground. The system does not absorb massive high energy strikes. It starts bleeding off the energy before the strike builds and thus minmiizes the effect. Mine has taken at least 17 direct hits that have been visually verified. All that energy had to go some where. The bleeding off theory has been pretty well discussed and discarded on the tower talk reflector. Read up on the Polyphaser site. They have some good information. Those lightning balls or porcupines have proven ineffective. The major work for lightning rods and ground systems is to divert the lightning away from the interior of buildings and process control systems in Industry. Home improvement stores sell #6 wire, ground rods and connectors. Read the new NEC code for tower and antenna grounding. There is a reason I went with #2. On Mon, 12 Jul 2010 21:21:24 -0700 (PDT), Tom Horne wrote: Can anyone make a recommendation, based on actual training and experience, as to what width and thickness of copper strap would be needed as the down conductor from the antenna mounts at the peak of my house roof, some twenty five feet above local terrain. I agree with the #2 recommendation. OTOH there is nothing that will protect an installation from the big atypical Positive lightning, or super strikes. That's the stuff that blows holes in airplanes. I have a a mount for an antenna at one gable end and a mount for a weather station sensor array at the other. What thickness and width should I use in the earth between the two Grounding Electrode Systems. I will drive five eighths inch copper rods, each eight feet long as far out from the foundation as I can get them or eight feet were possible. On one end that will be only six feet due to the proximity of the property line. At all of the other rod locations I will be able to keep them at least eight feet from any underground obstructions. To compensate for the proximity to the foundation wall to the first rod I will use rod couplers and drive it to hard rock or sixteen feet whichever comes first. I'm guessing that in keeping the remaining rods at least eight feet out from the foundation and sixteen feet apart that I will only have four rods total in a ring around the back side of the house. What is the best way to attach the copper strap to the support masts and eve brackets themselves? Do you know of anything that will make a good connection to the one inch galvanized iron pipes that I'm using for support masts? Can you recommend a technique for bonding the interior grounding buss at the operating position to the exterior vertical copper strap. I have no idea how that is usually done. The Polyphaser site has a tutorial on grounding tower legs and coax shields. this would be applicable to connecting to the 1" pipe. Use lots on NoAlox between the strap and pipe. 73 Roger (K8RI) John Ferrell W8CCW Roger, I like your response better than mine. Thanks, but just maybe I've been lucky since I finished up the system? It sounds to me like you have the ultimate solution. I arrived at my I'm not so sure about the "ultimate" part. operating point one step at a time and I quit working on the problem when I quit having problems! That's pretty much the approach I took...well that and you reach a point where any more gains become cost prohibitive.:-)) I bought all that copper before the price went up. I have a non-Ham friend that lives a couple of miles down the ridge from me that continues to have lightning related problems that may benefit from your advice. I will pass along the Wisdom. A couple years back, (after I had the system pretty well finished) we had one of those multiple strikes. It hit the power line out front, but neither I nor my neighbor directly across the road had any problems. However the neighbor to the North of him lost a lot of equipment. To that South of that neighbor across the road is a vacant lot that *had* a pine tree at the back of the lot. That tree literally exploded. All that was left of a 50 foot tree was a a 4' stump and a LOT of splinters. Well there was one piece about 4' long (give or take) stuck into the ground about 60 feet out. Thing is, only a little of it was sticking out of the ground. That thing must have had a LOT of force behind it. 73 Roger (K8RI) Thank you! John Ferrell W8CCW |
Grounding for Gable end bracket & mast.
wrote ... Szczepan Bialek wrote: Does exist an insulation (reasonably thick) which is not transparent for the radio-amateur frequencies? S* You obviously do not know that the amateur frequencies start at 1.8 MHz and include everything above 300 GHz. Within that range of frequencies, there are lots of materials that are "insulators" that have large dielectric losses. See: http://en.wikipedia.org/wiki/Permittivity and in particular: http://en.wikipedia.org/wiki/Permittivity#Lossy_medium " For frequencies at which dipole orientations cannot follow the applied field due to the viscosity of the medium, absorption of the field's energy leads to energy dissipation" You are a babbling idiot. I am collecting evidences. Thanks for your input. So, next question: The "energy dissipation" means heat. In case of the bare wire the air is heated. For isolated the insulation. Is it possible to burn off an insulation which have large dielectric losses? S* |
Grounding for Gable end bracket & mast.
So, next question: The "energy dissipation" means heat. In case of the bare wire the air is heated. For isolated the insulation. Is it possible to burn off an insulation which have large dielectric losses? S* I suppose yes, if the loss is high enough, and the applied power is high enough. However, a dielectric that lossy would greatly effect the electrical length of the antenna element, and removing it would change the characteristics and impedance of the antenna, so it may totally change the way your antenna behaves. Jeff |
Grounding for Gable end bracket & mast.
"Szczepan Bia?ek" wrote:
wrote ... Szczepan Bialek wrote: Does exist an insulation (reasonably thick) which is not transparent for the radio-amateur frequencies? S* You obviously do not know that the amateur frequencies start at 1.8 MHz and include everything above 300 GHz. Within that range of frequencies, there are lots of materials that are "insulators" that have large dielectric losses. See: http://en.wikipedia.org/wiki/Permittivity and in particular: http://en.wikipedia.org/wiki/Permittivity#Lossy_medium " For frequencies at which dipole orientations cannot follow the applied field due to the viscosity of the medium, absorption of the field's energy leads to energy dissipation" Yeah, so what? You do understand that they are referring to the molecular dipoles in the insulator, don't you? You are a babbling idiot. I am collecting evidences. Thanks for your input. Evidences (sic) of what, that you are a babbling idiot? So, next question: The "energy dissipation" means heat. Of course. In case of the bare wire the air is heated. Nope. This just shows you have no idea what permittivity and conductivity mean and you haven't a clue what you are babbing about. For isolated the insulation. Is it possible to burn off an insulation which have large dielectric losses? S* If you had the slightest understanding of the very first equation of the referenced link and the text that follows, you would know the answer is yes. Since you apparently read the link and still asked the question, I can only conclude you are an idiot. -- Jim Pennino Remove .spam.sux to reply. |
Grounding for Gable end bracket & mast.
wrote ... "Szczepan Bia?ek" wrote: See: http://en.wikipedia.org/wiki/Permittivity and in particular: http://en.wikipedia.org/wiki/Permittivity#Lossy_medium " For frequencies at which dipole orientations cannot follow the applied field due to the viscosity of the medium, absorption of the field's energy leads to energy dissipation" Yeah, so what? You do understand that they are referring to the molecular dipoles in the insulator, don't you? I do. This just shows you have no idea what permittivity and conductivity mean and you haven't a clue what you are babbing about. As you know I do not understand why in XXI century most scientists use the hydraulic analogy. Permittivity and polarisation are from the hydraulic analogy. Now conductivity and electrostriction should be used. S* |
Grounding for Gable end bracket & mast.
On Wed, 28 Jul 2010 20:37:43 -0500, tom wrote:
Actually, I am testing the chinese room argument. The operator's manual appears to be missing some pages. Interesting, thanks. That is similar to some of the new systems that let you store encrypted data and perform operations on them without decrypting them or knowing what you've done. something like a Secure Multiparty Computation. Hi Tom, Well, I let this free-wheel to see if our troll could rummage up the lost pages for his script. Apparently not. To extend the metaphor, I could also speculate that I was also testing a Zero-Knowledge proof (only so that I could enjoy the irony of the comment). 73's Richard Clark, KB7QHC |
Grounding for Gable end bracket & mast.
"Szczepan Bia?ek" wrote:
wrote ... "Szczepan Bia?ek" wrote: See: http://en.wikipedia.org/wiki/Permittivity and in particular: http://en.wikipedia.org/wiki/Permittivity#Lossy_medium " For frequencies at which dipole orientations cannot follow the applied field due to the viscosity of the medium, absorption of the field's energy leads to energy dissipation" Yeah, so what? You do understand that they are referring to the molecular dipoles in the insulator, don't you? I do. Obviously not or you wouldn't have posted anything you have posted. This just shows you have no idea what permittivity and conductivity mean and you haven't a clue what you are babbing about. As you know I do not understand why in XXI century most scientists use the hydraulic analogy. The hydraulic analogy is use to teach basics to children. Permittivity and polarisation are from the hydraulic analogy. Nope, you haven't a clue what permittivity and polarization are. Now conductivity and electrostriction should be used. Babbling, word salad, nonsense. -- Jim Pennino Remove .spam.sux to reply. |
Grounding for Gable end bracket & mast.
wrote ... "Szczepan Bia?ek" wrote: As you know I do not understand why in XXI century most scientists use the hydraulic analogy. The hydraulic analogy is use to teach basics to children. The fluxes are for students. The divrotH = 0 also. Permittivity and polarisation are from the hydraulic analogy. Nope, you haven't a clue what permittivity and polarization are. Now conductivity and electrostriction should be used. Babbling, word salad, nonsense. Electrostriction is a new. The "" For frequencies at which dipole orientations cannot follow the applied field " is rather old. Do not stay in Heaviside water. S* |
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