I would like to tie the gounds to a common building ground, but I cannot seem to come up with anything that does not seem to contribute to the problem. The only way to achieve a straigtline connection between the tower and the building ground is to go throug the house. That in itself would not pose a problem, but I am not comfortable with the thought. John Ferrell http://DixieNC.US ----- Original Message ----- From: "Nate Duehr" To: Sent: Friday, March 05, 2004 5:27 PM Subject: Re: [OT:] More stupid electrical tricks... > On Mar 5, 2004, at 10:26 AM, John Ferrell wrote: > > > This happens in my shop frequently.I disconnect the antenna & rotor > > when not > > using it and it dangles at about 7 feet off the floor, When it starts > > ticking, I shut down computers and prepare for lightning. Yes, the > > tower is > > grounded... > > Mmm... they really should install a copper entrance panel connected to > ground via wide copper strapping and get you some Polyphaser devices to > pass all the cables through. > > The tower ground needs to be bonded to the building ground and the > "dangling" cables need to be plugged into a separate grounding block > when they're not in use. Otherwise they're a fire hazard, most > likely. > > A direct strike to the tower will charge it and everything connected to > it to a high enough potential that the electricity will be looking for > ANYTHING that looks like a ground, and the tower's ground can't > instantaneously bleed off all that charge -- the potential of those > cables WILL be high enough for them to find a place to arc over to. > ESPECIALLY if the tower is not bonded to the electrical ground -- that > has to be done correctly also. (The bummer with this for us RF guys is > of course, that a nicely protected electrical ground system usually > ends up resonant at some darn frequency we want to use.) > > Polyphaser's website has some nice engineering information about how to > properly ground a tower "system", not just the tower itself. After > seeing firsthand what a solid direct hit can do to a residential > dwelling when my dad's house took a direct hit last year, I carefully > think about all paths to ground any lightning that hits any of my > antennas will take... ALL of them. > > Nate Duehr, nate@natetech.com > > -- > http://www.piclist.com#nomail Going offline? Don't AutoReply us! > email listserv@mitvma.mit.edu with SET PICList DIGEST in the body > -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu