[TowerTalk] how best to protect RC ham gear from lightning

[Larry Banks]

Hi Dave,

I would suggest you purchase and read the new ARRL book: Grounding and 
Bonding for the Radio Amateur.

It has everything you need.

73 -- Larry -- W1DYJ


-----Original Message----- 
From: David J "Dave" Windisch
Sent: Friday, July 27, 2018 11:43
To: towertalk at contesting.com
Subject: [TowerTalk] how best to protect RC ham gear from lightning

Subject: how best to protect RC ham gear from lightning



Hi, Steve, and all concerned:

I'm simply nervous and jerky about how best to protect RC ham gear from
lightning, since I won't be around to disconnect cables "the old way".



My remote site is a former AT&T microwave relay site, on 920ft ASL property,
near Cincinnati OH.

There's a pic on my QRZ page.

The tower is 120ft tall to the approach beacon plate.

The bunker is about 57ftX57ftX16ft.



A retired AT&T engineer familiar with these sites, told me there is a ground
mat under the entire site, to which _everything_ is connected, probably even
the fence around the site.

20-mile el profiles to major world DX regions taken from GOOGLE EARTH, as
well as HFTA, show the site as "a nice bump" of good ole Ohio farm dirt,
iow, a good potential lightning target.

Yet, minute inspection of the entire tower top yields nothing I can
interpret as evidence of lightning strikes during the 50-odd years the site
has existed: there are no telltale marks in the paint or galvanizing.



Electricity, antenna feeds, and internet enter the bunker, from under
ground, at a single point.



A home 1.9mi away on 750ft ground(!) took a _major_ hit last summer. Lotsa
damage, no injuries.



My thoughts, so far, are to start from the highest point, with:

1.   A mast with rotator, bonded to the tower, with the topmost antenna
down, say, 5ft from the mast top so the mast forms a sorta lightning rod

2.   Cable shields tower-bonded top and bottom

3.   All cables in a trench to the single point bunker entry

4.   Control cables protected by, eg, ICE or similar voltage clamps



I'm stuck here:

How can I best protect the sensitive data and rx/tx ports on the gear, which
will be set up on a grounded metal operating table, inside the bunker?



Brgds,

Dave, N3HE

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