Grounding TV antenna tower

What is the proper and best way of grounding a tv antenna at the top of a 40' tower? I have a cottage on lake huron, and the tower is going to be the highest metal point for quite a few hundred feet. I am concerned about damage when lightning hits the tower or antenna. Also- Should a grounding jumper be run around the rotator to ground the antenna and mast? Thanks
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Ahh..... remembering days of my youth,,,,,,
ok, go to http://www.arrl.org /
We all learned about towers, big arrays, et. al. You need lightning protection and other things that will protect your property.... They all do work, given the antenna farm I had for years,,,,,,,
--Paul WA1VPY....
snipped-for-privacy@gmail.com wrote:

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Ahh..... remembering days of my youth,,,,,,
ok, go to http://www.arrl.org /
We all learned about towers, big arrays, et. al. You need lightning protection and other things that will protect your property.... They all do work, given the antenna farm I had for years,,,,,,,
--Paul WA1VPY....
snipped-for-privacy@gmail.com wrote:

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snipped-for-privacy@gmail.com wrote:

grounding the tower will just make it more attractive to lightning. However, it will protect you since the lightning will enter the ground and not the house.
You probably need a lightning rod or something to attract or disipate the lightning, which will also be grounded.
--
Thank you,



"Then said I, Wisdom [is] better than strength: nevertheless the poor
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dnoyeB wrote:

grounded tower with lightning rod on top of tower and sufficient ground cable to sink the current into the ground (there is a formula, can not remember)
The antenna is shielded due to an umbrella effect of the higher point of the lightning rod.
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wrote:

My gosh, such misinformation.
An antenna still has a good chance of getting hit by lightning directly even if there is a lightning rod nearby. Lightning is random by nature.
The tower is already grounded by virtue of it probably being bolted to a concrete pad at ground level and being made of metal. Grounding it more will not increase the electric field at the top.
Ground wire for the antenna provides a lower impedance path to ground which the majority of the current will follow. A direct strike can still send current through other paths. Sufficient sizing of the ground wire will minimize the current in these paths. This obvoiusly allows you to control where that current flows instead of leaving it to nature at the base of the antenna.
All you need is a spark gap, a ground wire and a ground rod. The basic diagram is included with the instruction manual of every consumer electronics equipment that connects to an antenna like a TV or VCR for many years. There are also off the shelf grounding kits anywhere they sell antennas, complete with instructions (you may have to buy a seperate grounding rod)
Grounding of all the splitters (particularly the first one) adds a measure of additional protection for you and your equipment. You can ground the shield of the cable anywhere you want, the center conductor is floating (WRT DC current) and connected mainly to the transformer windings in the splitters with no actual (DC) direct path between the antenna and the TV. Current in lightning will fuse this path open in a flash, most current will enter the house via the shield which may be DC connected to the antenna.
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snipped-for-privacy@gmail.com wrote:

Besides what has already been mentioned here, don't forget to buy the proper lightning arrestors for any coax cable, rotor cables, etc. They also should be grounded to the copper rod that grounds the tower. They also make fuses for this purpose. Every little bit helps.
J
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How would one make any part of the tower higher than the antenna? When a rotor is used, which I need to use due to the distance involved, there is no feasable way of having any rod stick higher than the antenna. Also, if grounding the tower makes it more attractive to lightning, why are tv antennas on roof tripods usually grounded? Thanks
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snipped-for-privacy@gmail.com wrote:

Like I said because if lightning does strike you want it to seek ground by following a path OUTSIDE of your house. Without grounding the antenna properly through a path outside of yoru house, if lightning does strike it, it will ground itself through a path within your house which may significantly more hazardous to your health.
grounding the tower can also make it less likely to endure a direct blast if it is able to dissipate enough energy before it can build up. A lightning rods true purpose is to leak energy to prevent the massive burst of energy that comes with a direct strike.
As for making the tower higher than the antenna, you gotta do what you gotta do...
--
Thank you,



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wrote:

Use a dedicated grounding rod. do not connect to your safety ground (third prong on the receptacles). You can connect to the house ground only at the grounding rod, not anywhere before.

True purpose is to provide a lower resistance path to ground than would otherwise be found

The lightning rod is unnessary, simply ground the antenna via a spark gap and the shield of the antenna cable.

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A lightning rod higher than the tower is ideally connected to a large copper cable properly grounded with multiple ground rods driven 8 feet or more into the ground, for everyones safety this groumd must be connected to the main house ground, at the service entrance, which must be bonmded to the homes plumbing system and if you have city water the meter must have a jumper in case its removed for some reason.
multiple grounds that arent bonded together can kill or cause a fire
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Andy comments:
In addition, I would ground the coax outer shield conductor to the tower , which should have a ground to earth SEPARATE from the concrete mounting block..... This will have NO effect on the signal inside the coax, and in the event of a lightning strike, the center conductor, if hit, will arc to the coax shield anyway...... A lighning arrestor wouldn't hurt, tho... It will help to
protect your inside equipment, tho the results are unpredictable....
Andy W4OAH
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Lightning wants earth ground. It will take a destructive path through rotor, pre-amp, or receiver IF you don't provide an electrically shorter path. One technique involves a lightning rod above the antenna and connected to earth. Another puts electrical bypasses around things such as the rotor. There is no way to stop or block lightning. For example, any post that suggests fuses for protection means basic concepts - as even demonstrated by Franklin in 1752 - were not learned. There is nothing (ie a fuse) that will stop or block such transients. And yet that is how so many ineffective surge protectors are promoted.
Most essential to protecting a tower, et al is earth ground. The system component little seen is THE most critical component of a tower protection system. An industry professional demonstrates the concept. In this case, tower and building are treated as separate structures; each must have its own single point earthing. Any connection to either structure must first connect to its single point ground. To make both structure's earth ground even better, both earth grounds are interconnected: http://www.erico.com/public/library/fep/technotes/tncr002.pdf
Having first established this most critical 'system' component, we then move up the tower to bypass anything that may be damaged when lightning makes an electrical connection to earth. Bypass so that lightning will see that earth ground by a non-destructive path.
Same principle used on the tower must also be used in a building. That means connection from tower to building must connect (every wire in every cable) short to the building's single point earth ground before entering building. This connection made by hardwire (ie coax cable) or via an arrestor. Notice what an arrestor does not accomplish. It does not provide protection. A arrestor's function is simply to make an electrical connection short to earth. Note the repeated reference 'short'. All incoming wires (from tower, AC electric, phone) must enter at a common service entrance so that all are earthed short to same single point earth ground.
Another has demonstrated the concept: http://www.knology.net/~res0958z /
Earthing does not make your location more attractive. If lightning needs that connection to earth, then lightning is going to strike. So which electrical path do you want lightning too take? Franklin demonstrated it in 1752. Lightning sought a conductive material to earth ground - wooden church steeple. Notice how non-conductive materials are now considered conductive. Franklin provided lightning with an electrically shorter path to earth. His lightning rod was only as effective as its earth ground. Your protection does same thing as demonstrated in the above URLs.
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