[Boatanchors] Re: [AMRadio] Tower Construction

[Glenn Little WB4UIV]

When a ground wire (to protect from lightning) is run through concrete, it 
MUST be run through something non conductive to isolate it from the 
concrete. If it is run through something metallic, the metal acts as a 
choke impeding the energy of the lightning from going to ground. If in 
direct contact with the moist concrete, steam will be generated at a 
strike, possibly exploding the concrete in the area of the ground wire.

In a previous job I had to do field visits for evaluating lightning damage. 
Motorola R-56 and MIL-HDBK-419 are great references. If followed, you will 
incur minimal lightning damage. If you elect to not follow these, have a 
very good insurance policy.



73
Glenn
WB4UIV
Acting Chief Engineer WCIV TV

At 07:13 AM 06/12/06, Ed Swynar wrote:
>Hi Steve,
>
>By running the ground through the concrete itself, do you not risk the
>potential of the block being damaged, should your tower suffer from a direct
>lightning strike...? Or is this merely another "...urban legend" I've heard
>about tower installation, that has clung to the grey cells lo these many
>years...? Hi Hi
>
>~73~ Eddy VE3CUI - VE3XZ
>
>
>
>----- Original Message -----
>From: "Stevan A. White" <w5saw at pathwayz.com>
>To: "'Discussion of AM Radio'" <amradio at mailman.qth.net>;
><boatanchors at mailman.qth.net>
>Sent: Sunday, June 11, 2006 11:32 PM
>Subject: RE: [AMRadio] Tower Construction
>
>
> > DO RUN THE GROUND THROUGH THE CONCRETE!  Take a look at the information on
> > this site first though.  You may be glad you did.
> >
> > http://www.scott-inc.com/html/ufer.htm
> >
> > Best Regards,
> > Steve White, W5SAW
> > SW Commercial Electronics
> >
> >
> > -----Original Message-----
> > From: Ed Swynar [mailto:gswynar at durham.net]
> > Sent: Saturday, June 10, 2006 2:16 PM
> > To: Discussion of AM Radio; boatanchors at mailman.qth.net
> > Subject: Re: [AMRadio] Tower Construction
> >
> >
> > Hi Dave,
> >
> > I have a 48' tall, tapered, self-supporting "Delhi"-brand tower --- 6
> > sections at 8' long each.
> >
> > The prescribed / manufacturer's recommendation is to bolt a 3' straight
> > formed extention at the base of each leg (total of 3), & to "suspend"
>these
> > (a temporary wooden "cradle" will do admirably, as the cement sets) in a
> > hole dug 4' square, & 4-1/2' deep --- the cement is to come but a few
>inches
> > below the bottom legs of the actual tower section.
> >
> > Oh yes --- the bottom 1' of the square hole is to be "belled" outward a
> > foot, or so.
> >
> > The documentation says this is good for heights of up to 64', or so...I've
> > never gone beyond 48', & have never, EVER had an ounce of trouble in the
>two
> > locations that I've had my tower up.
> >
> > BTW, the top of the tower as an old Cornell-Dubelier AR-44 rotator, & a
> > 3-element Hy-Gain TH3 MkIII triband yagi...
> >
> > Use "industrial"-grade coarse cement, & do NOT run any ground leads
>through
> > the block itself!
> >
> > ~73~ Eddy VE3CUI - VE3XZ
> >
> >
> >
> > ----- Original Message -----
> > From: "david knepper" <collinsradio at adelphia.net>
> > To: <AMradio at mailman.qth.net>; <boatanchors at mailman.qth.net>
> > Sent: Saturday, June 10, 2006 12:44 PM
> > Subject: [AMRadio] Tower Construction
> >
> >
> > > I am thinking about buying a stick of Rohn 55G in cement with about 3
> > > or 4 feet sticking out of the ground.  I wonder how many sections of
> > > 55G I
> > could
> > > mount without guys.  I do have a strong base plate for the 55G but
> > cementing
> > > a section seems to be sturdier.  Any thoughts?
> > >
> > > Thanks
> > >
> > > Dave, W3ST
> > > Publisher of the Collins Journal
> > > Secretary to the Collins Radio Association
> > > www.collinsra.com - the CRA Website
> > > Now with PayPal
> > > CRA Nets: 3805 Khz every Monday at 8 PM EST
> > > and 14255 every Saturday at 12 Noon EST
> > >
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> >
> >
> >
> >
> >
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> >
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>
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