[TowerTalk] tower & antenna project questions
Bill Aycock
billaycock at centurytel.net
Thu Mar 11 19:49:56 PST 2010
Thank you Jan--
I thought it was at least that old. That opinion has been disproved many
times, which is why the ARRL took the reference out.
I have seen concrete explode, and it took a LOT of local heat to do it. On
the occasion when I saw it, it was Rocket fuel. The ground system described
is, essentially, an "Ufer" ground, where there is connection between the
rebar cage and the ground system. The Army uses this system to protect
explosive storage facilities. Successfully. I worked in one, designing
Rockets, for 38 years. Go to the Wikipedia and look up Ufer.
The Lightning caused steam explosion is a myth. What IS bad, and can cause
concrete cracking, is having rebar in contact with both the ground and the
cement at a boundary. In this case, the steel rusts, admits water, and
cracks appear on freezing. They use Copper at the transition to stop that.
I have not seen a documented case of a Lightning-caused concrete explosion.
----- Original Message -----
From: "Jan Wise" <Wisecrafter at suddenlink.net>
To: "'Bill Aycock'" <billaycock at centurytel.net>
Sent: Thursday, March 11, 2010 7:31 PM
Subject: RE: [TowerTalk] tower & antenna project questions
> That came out of the ARRL Antenna Book 16th edition Copyright 1991.
> It is under bases for towers in the index. Pp 22-9 TOWER BASES
>
> -----Original Message-----
> From: Bill Aycock [mailto:billaycock at centurytel.net]
> Sent: Thursday, March 11, 2010 5:20 PM
> To: wisecrafter at suddenlink.net; Tower and HF antenna construction topics.
> Subject: Re: [TowerTalk] tower & antenna project questions
>
> That must be an OLD handbook. Can you give me the year, chapter and page
> where this old wives tale is? I'd like to find it in print, jut once.
> Bill--W4BSG
>
> ----- Original Message -----
> From: "Jan Wise" <Wisecrafter at suddenlink.net>
> To: "'Tower and HF antenna construction topics.'"
> <towertalk at contesting.com>
> Sent: Thursday, March 11, 2010 4:22 PM
> Subject: Re: [TowerTalk] tower & antenna project questions
>
>
>>I am not sure, but I think if you look at the Hand Book It will state that
>>you do not want the tower or anything else to be grounded that goes
>>through
>
>>concrete. The reason being that a hit from lightning
>> Will cause the concrete to explode. If I am wrong someone please let me
>> know !
>>
>
>
>
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