And, for both CATV and phone, their interest is in protecting *their* physical plant, not yours. You are the sacrificial element in their protection system. An interesting point. Does anyone know if
There's a general NEC requirement that all grounds have to be tied together. _______________________________________________ _______________________________________________ TowerTalk mailing list Tow
While there are specific bonding requirements in the NEC, the NEC is part of the National Fire Code, and as such may or may not be adopted by individual states or municipalities. There are other bui
It makes sense that all grounds be tied together, but a question is how? If you have all-copper plumbing in your house and all grounds are bonded to that, are they all tied together? My old antenna b
Good point, Don. The ground potential, voltage on the ground wire, for the power company may have risen during the strike because it (and your station ground that was tied to the power company ground
Hi, JC; I had been pondering your earlier post regarding need for a perimeter ground or loop. PolyPhaser made an argument in their earlier book, Grounds for Lightning Protection, for this and I obser
Author: "K8RI on Tower talk" <k8ri-tower@charter.net>
Date: Tue, 11 Jul 2006 13:07:47 -0400
Here, the local code requires it. Of all the CATV is the poorest at complying but they do comply or the electrical inspector will pay them a visit. Coming back is a lot more expensive than doing it
How to tie really depends on why you're tying. The NEC calls out some fairly specific rules including size of conductor, lack of splices, routing, etc. Mike Holt enterprises has a free downloadable b
Hi Red, The ground situation here has been constantly improving. When we moved in there was one ground rod (presumably 8') tied to the electric service entrance with #10 solid copper wire, and also t
Yes. If you think of lightning as DC, you're likely to be in serious trouble. IEEE studies show that the energy content in lightning has a broad peak around 1 MHz, with significant content well above
ORIGINAL MESSAGE: -- REPLY SEPARATOR -- That raises an interesting question. As I understand it, lightning really does flow in one direction, making it DC but having a square-wave nature. Is that whe
Rather than thinking of lightning as an electrical current flowing from ground to cloud or vice versa, I find it more interesting to think about what it is composed of: plasma. The free electrons and
ORIGINAL MESSAGE: -- REPLY SEPARATOR -- As I understand it, plasma (in the general sense) can exist with or without current flow. In the absence of external heat, plasma will quickly recombine into n
Here's a thought (probably mentioned previously). Assuming a tower has a good ground system, we still have cables connecting the antennas and other equipment on the tower to the house and electronics
Author: "K8RI on Tower talk" <k8ri-tower@charter.net>
Date: Tue, 11 Jul 2006 16:04:27 -0400
Lightning is a complicated and unpredictable phenomena. Yes, it's essentially DC...pretty much, almost, sorta, but: There are both negative and positive strikes. The so called super strikes are thou
Author: "K8RI on Tower talk" <k8ri-tower@charter.net>
Date: Tue, 11 Jul 2006 16:15:13 -0400
Grounding the shiled of the coax is far more effective. Running through the pipe does form a choke of sorts, but it's still going to let a lot through. Roger Halstead (K8RI and ARRL 40 year Life Mem
Yes Bill, you have it correct. When building an ideal ground system for lightning it should end up being an excellent RF ground system for a 160 meter vertical. 73 Gary K4FMX _______________________
The plasma trail is created by the step leader making contact with a streamer. The main strike follows the low impedance plasma trail. Being a low impedance allows the high currents in the strike to
Author: "K8RI on Tower talk" <k8ri-tower@charter.net>
Date: Tue, 11 Jul 2006 16:44:56 -0400
Plasma can be created with high temperature, voltage, or both as you do have a high temperature once the electrons are stripped off the atoms and molecular bonds broken. The only difference I'd use
If you run them into conduit you need to ground them to the conduit or they will arc. It is best to ground all cables to the base of the tower and also at the shack entrance where protective devices