Franklin method proven once again...thanks Ben!!! I have no qualms recommending it to anyone...
Jaime Solorza On Jul 25, 2017 11:55 AM, "George Skorup" <[email protected]> wrote: We're on a tower that had no air terminal. We'd lose gear occasionally. Owner added an air terminal bonded to the top section. The frequency of lost gear didn't change much. They ran a conductor from the air terminal all the way down to the grid and we haven't lost anything since, ~2 years. We were on another tower for years and always lost gear. 500' FM, cell, paging. Lots of shit. Halo air terminal on top, 2/0 coming down. We abandoned it because every year, every single piece of copper on the ground to about 10 feet up the tower would be missing. It would not be replaced until the fall. Then it was all gone again the next spring. Lot of good it does in the winter. On 7/25/2017 12:38 PM, Paul McCall wrote: Lewis, On option 2, if you are just leasing space on a tower such as Crown Castle, etc., I have doubts that they would allow me to install the 8’ rod at the top and run the 2/0 down the tower. So, would you, just do a 2/0 starting at your equipment area, bond to the tower at that height, and go down from there? On the “bonding everything together” scenario, if the tower ground is not as good as the other grounds going down the tower (mine, the cellular companies, etc.) won’t the differential in impedance cause the lightning to 1) likely take the lesser impedance path down and/or 2) have the voltage not rise and fall together and bad things happen from that? Paul *From:* Af [mailto:[email protected] <[email protected]>] *On Behalf Of *Lewis Bergman *Sent:* Monday, July 24, 2017 1:47 PM *To:* [email protected] *Subject:* Re: [AFMUG] Tower Top Grounding discussion On 1. it will be really difficult to completely isolate a piece of equipment unless it is designed to float but good luck. If you are truly going to isolate everything from ground then you won't need to worry about #2 as all will float. You should check that the antenna you are using don't require a ground plane. On 2. I Cadweld a 2/0 jacketed to an 8' rod at the top of the tower, not isolated. I then bond (15 ton Hydraulic Crimp) it to a bus bar 5' below the top for equipment grounds. Anywhere else there is a cluster of equipment I also put a bus bar. I then take that 2/0 to the bottom to the last bus bar and then into the ground ring. 1. *Wondering what materials people are using to isolate their mounts?* What is sufficient? Would the rubber from a thick radiator hose be enough to keep the lightning from coming through? Double thicknesses? One consultant recommended starboard, but I am not sure how I will craft that into a work piece that would mold around a tower leg and be able to grip it. 1. *What size wire should be going down the tower to bond to my tower / electrical ground? * I am assuming it should be insulated but is normal THHN jacketing enough to have it truly isolate from something jumping over or does it have be in conduit. Paul Paul McCall, President PDMNet, Inc. / Florida Broadband, Inc. 658 Old Dixie Highway Vero Beach, FL 32962 772-564-6800 <%28772%29%20564-6800> [email protected] www.pdmnet.com www.floridabroadband.com
