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[TowerTalk] Lighting protection for roof mounted tower

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Subject: [TowerTalk] Lighting protection for roof mounted tower
From: "Ray" <>
Date: Wed, 12 May 2010 21:36:10 -0700
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I have an 8 ft roof tower that I am debating where and how to install. My
concern is lighting protection and the way I would like to run the coax.
This roof tower will hold a 3 el 6m yagi, small yagis for 2m and 440mhz, and
a 2m vertical on top. My radio room in almost in the center of the house.
The run for all my HF coax and cables from the station to the Single Point
Ground is about 30 ft long running under the raised floor. We do get late
summer monsoon rains and lightning. 
First option: mount the roof tower above my shack. I would run the coax
cables and #4 grounding wire straight down, through the roof and attic and
into a living room divider wall with a 90 degree sweep to my shack. The coax
run would be about 30 ft. There are #4 ground wires both in the attic and
raised floor that I could connect the roof tower ground wire to. 
Second option: mount the roof tower at about the same place and run the coax
to the edge of the roof, down to ground level, then into my SPG. The total
RG8 coax run for each antenna and ground wire would be about 85 ft. This
length of coax can start to lead to losses on the VHF frequencies.
My concern is about running the roof tower cables thru the house thereby
creating a possible lightning path into the house vs. making the longer
cable runs to the SPG. I do have two 70 ft HF towers nearby with quite an
extensive ground system on each. All ground rods (about 50) are
interconnected with #4 wire to each tower, the SPG and the house mains
input. The roof tower would be somewhat dwarfed by the two HF towers, but
when lighting strikes, we all know that it will go anywhere and everywhere. 
What are the thoughts, comments and opinions about bringing my 6m and VHF
cables through the house? I would sure like the shorter coax runs, but
safety is my concern.
Chino Valley, AZ

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