[time-nuts] New NTBW50AA

Lee Mushel herbert3 at centurytel.net
Sun Sep 15 18:16:23 EDT 2013


Lightning is certainly one of Old Mother Nature's principal weapons as well 
as being extremely unpredictable.   My House/Shack is on the side of a hill 
with the Antenna Farm on top of the hill about 120 yds away with an 
additional 30 ft. of elevation.   There is a metal "lightning rod" extending 
high enough to provide a "cone of protection" for the house and is grounded 
directly.   And there are five other metal antennas on that roof, two to a 
separate ground and three to still another which is close to the shack 
"ground field" which is three additional  ground rods.   All ground rods I 
mention are the standard 8 ft. copper plated steel items.  Each of five 
antennas in the antenna field also have individual ground rods and I guess 
if you follow the cable shields you could say that they are all connected 
together.    A couple of years ago I counted all ground rods and came up 
with 23.   Before all of the metal was added and the "lightning rod" was the 
only metal extending about 20 ft. above the roof and we had an electrical 
storm my wife would complain that she could feel her hair trying to rise in 
response to the field coming from the cable which ran across the roof and at 
it's closest point was only 6-7 ft. from her head as the crow flies.   But 
after all the additional metal was added in the form of antennas with 
grounds  she no longer complained.

I do not claim to understand what goes on around here at an elevation of 
about 102 ft. above the valley floor but I believe that we have been 
"fortunate"  (or lucky if you prefer that word) and we have so much metal in 
the air that most "discharges" are not of the type that is accompanied by 
thunder!   Two years ago we had a tree die that was no more than 30 ft. from 
the house.   Since I have not always been able to accurately predict where 
trees will fall that I cut myself I hired a professional to take it down and 
he took one look at it, reached up and stripped off a piece of bark and 
commented, "See those lines?   This tree was struck by lightning.   That's 
what killed it!"   But no lightning related damage to structure or equipment 
here for nearly 15 years!

My only thought on the subject was that only a fool would fail to disconnect 
an antenna that rises above the house roof  during an electrical storm.   I 
freely admit that I have several ham radio VHF antennas  (and a GPS antenna 
supplying the disciplined system for frequency reference) well below roof 
peak level  (clear view to south for GPS, of course) that I do not 
disconnect from inexpensive radios maintained for the purpose.

This is risk I accept.   And I certainly have seen paths followed by 
lightning that are truly amazing!  ....and horrendously damaging.  Never 
forget that you only live once and you do have a perfect right to enjoy your 
hobby without fear.

Regards,

Lee A. Mushel   K9WRU


----- Original Message ----- 
From: "quartz55" <quartz55 at hughes.net>
To: "Discussion of precise time and frequency measurement" 
<time-nuts at febo.com>
Sent: Sunday, September 15, 2013 12:13 PM
Subject: Re: [time-nuts] New NTBW50AA


 .  I'm not thrilled having it above the beams, it's the highest metal thing 
in the area and most likely more prone to lightning than anything else 
excpet the trees and it will blow around a bit up there as well as rotating 
once in a while.  I did have a strike here once, but it was down by the barn 
and was looking for the underground telephone cables, it blew apart a post 
and knocked off the boards, it was maybe 100 yards from the shack.  It 
wouldn't be much of a problem to dig a tiny trench to the fence and I may 
try that after this precise survey is done, then do another and see if 
anything changes.  I could hide it i
> n a bird box at the fence too.  After all at this point I'm just playing. 
> I'll eventually make up my mind.  Also, I don't have an attic, so that's 
> not an option.
>
> Dave
> N3DT
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