For us, we also do an arrestor before the radio, a gas discharge unit. We also use an arrestor before the POE injector and anyplace else a cable enters a structure or piece of equipment. We use shielded and flooded Cat5 cable with a static drain wire attached to shielded cat5 connectors and also grounded. (The static can give you problems just as much as lighting) For ground, we "try" to stay away from just wire and use copper strap where we can. 1.5" to 2". In a pinch I've cut copper pipe in half to give me the strap needed. (Never make any sharp angles with the grounds, lightning likes to go in a straight line) On our MT boxes, I put a thin copper sheet on the inside and outside where the gas discharge is inserted and attach a copper ground terminal to it on the outside and use that to ground to the structure we are on. For good measure, I use a lighting rated surge protector wherever we get commercial power. 20 bucks here from Ace Hardware. Says they will pay for up to $50,000 in damages caused by lightning. (I always thought, the surge has 6 outlets to plug things in - - What 6 things could I possibly have that would total $50,000 and if I did, why would I trust a $20 adapter from Ace Hardware???) What we do is probably overkill in our area but we haven't lost a unit yet. I obviously modify everything, it's a curse.
The experts in all this are the cellular and broadcast tower people. Look around on the methods they use. Polyphaser is a good place to look for ideas, http://www.polyphaser.com/ I can't afford much of what they sell but it's good to see what's out there. -----Original Message----- From: wireless-boun...@wispa.org [mailto:wireless-boun...@wispa.org] On Behalf Of James McBryan Sent: Wednesday, September 16, 2009 11:52 PM To: wireless@wispa.org Subject: [WISPA] Need Lightning Arrestor Advice Hello all, I am part of a group installing a wireless network in rural Honduras for a growing educational system with a chapter of Engineers Without Borders (http://ewb-usa.org). We are creating a 7 node wireless network spanning a 3 mile radius. Since Honduras is very prone to rain storms and lightning strikes, we need to protect our equipment from the lightning. We plan on doing the following: 1) Place an arrestor between the radio and the antenna 2) Place an arrestor in the POE injector Some of the following criteria we are thinking: Amount of lightning strikes: One or Many Insertion Loss: Small as possbile Frequency : 2.4-5.8 GHZ When searching the internet, I see many many types of lightning arrestors given my criteria. Does anyone have any recommendations through their experience with lightning arrestors? What do you use? Thanks! James ---------------------------------------------------------------------------- ---- WISPA Wants You! Join today! http://signup.wispa.org/ ---------------------------------------------------------------------------- ---- WISPA Wireless List: wireless@wispa.org Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/ -------------------------------------------------------------------------------- WISPA Wants You! Join today! http://signup.wispa.org/ -------------------------------------------------------------------------------- WISPA Wireless List: wireless@wispa.org Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/
