Roger Block, author of the 'Grounds' book and PolyPhaser's
founder and chief technicable guru wrote the book, and most
of his advice, based on typical commercial procedures where
the tower is relatively close (<=~35')to the building. PP advice
for the length of the radials indicates going past ~75' a waste
of resources as the [ground] inductance would have shunted
off almost all of the surge current by then. If the earth was
real poor, probably 100-foot radials would be recommended (as
are suggested for mountain top applications).
The technical consultants at PP kicked this around
so that we could present a united front on this issue.
We decided that 50' would be a good dividing point.
Certainly there is nothing to be gained once past 75'.
The need to even have this bond in an amateur
application, where the coaxial cable(s) are brought
down to ground level, is questionable. It probably
does not do much if anything, but it certainly can't
hurt matters either! The commercial world, where
the cables are usually brought across 7~15 feet AGL,
does require this bond however. From what I recall, it
lowers the Epk between the cables and the earth. For
those who wish to know more on that subject (or challenge
it), send your messages to <krand@polyphaser.com> and
*not* to me.
73,
Bob AA0CY
----------
From: Pete Smith[SMTP:n4zr@contesting.com]
Sent: Sunday, July 05, 1998 10:45 AM
To: Bob Wanderer
Subject: RE: [TowerTalk] Attach ground wires to Trylon Tower?
At 08:23 PM 7/3/98 -0700, you wrote:
....
>* My tower is about 50 feet from the house. From various TowerTalk posts
>recently, it sounds like it is NOT a good idea for me to take a run of
>copper and ground rods and tie the tower and the bulkhead panel together.
>The concept of doing this is complicated further because I would have to
>pass over buried electrical cables (and telephone and cable) to do it.
>>>At 50' you are getting to the point where the two sites won't "see" each
>other. If you have spare material available, you may as well run this bond,
>otherwise don't bother. If you do run it, however, do it sans ground rods.
I'm confused -- I thought thePolyphaser advice was to bond regardless of
distance, in an effort to prevent the two points - tower ground and shack
ground - being at different potentials. Or is it safe to assume that for
long runs there is enough inductance in a tower-to-shack ground wire to
effectively negate the bond in strike situations?
73, Pete Smith N4ZR
n4zr@contesting.com
"That's WEST Virginia. Thanks and 73"
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