Re[4]: [TowerTalk] New Tower Construction - Questions
R. Otto
R. Otto" <N8NGA@one.net
Thu, 31 Aug 2000 11:56:20 -0400
Hello Carl,
<laugh> OK, OK, OK...........let me clarify!!
I meant that the wire should be bent on a 12" radius -- not that the
wire had a 12" radius <G>
It's interesting to see how many towers have the ground wire bent (and
coax too!!) into sharp corners or tight radii to keep it tucked closee
to the structure. This negates/significantly reduces the ability of
the wire to conduct the charge to ground. It looks nicer perhaps, and
helps keep it away from kids and such.........but it's against good
electrical practice.
73's from.......
R. Otto
N8NGA@one.net
Cincinnati, Ohio
**********************************************
DXCC 10M ** DX is !! ** WAS 10M
There is a very fine line between
"HOBBY" and "MENTAL ILLNESS"
**********************************************
When trouble arises and things look really bad,
there is always one individual who perceives a
solution and is willing to take command.
VERY OFTEN THAT PERSON IS CRAZY!
**********************************************
Thursday, August 31, 2000, 11:42:00 AM, you wrote:
CS> Hello R. Otto,
CS> You say: "making sure your ground wire doesn't have a radius less than 12
CS> inches", that's one H*** of a huge wire.
CS> Is that a misprint??
CS> 73, Carl VE9OV
CS> -----Original Message-----
CS> From: owner-towertalk@contesting.com
CS> [mailto:owner-towertalk@contesting.com]On Behalf Of R. Otto
CS> Sent: Thursday, August 31, 2000 11:41 AM
CS> To: Bill Coleman; towertalk@contesting.com
CS> Subject: Re[2]: [TowerTalk] New Tower Construction - Questions
CS> Hello Bill,
CS> You might want to think about your ground rod plan some more. I too
CS> thought "the longer the rods, and the more rods I use, the better".
CS> When I read the Polyphaser data, I found differently. They seem to
CS> suggest that length of rod over a certain amount will be wasted. They
CS> talk about ground rods on the order of 4', no more than 8' unless you
CS> have some specific reason for length. Additionally, they say that
CS> additional ground rods on a single line don't really help much as it
CS> takes too long for the charge to get to the extra rods. They also talk
CS> about "sphere of influence" (I think that's correct -- doing this from
CS> memory). What this means is that if you put ground rods too close
CS> together, the ground is saturated with the charge from one and the
CS> charge from the second one, if too close to the first, will not be
CS> absorbed from to ground.
CS> Also, please note the importance of; A) making sure your ground wire
CS> doesn't have a radius less than 12" (or some large amount *memory*
CS> <G>), and B) that it's important to take your coax all the way to the
CS> ground before taking it in your shack. Don't trust my memory here
CS> though..........use the data Polyphaser recommends. I'm just trying
CS> to point you in the right direction on several issues I found
CS> interesting, and sometimes contradictory to what I've seen posted.
CS> I had to read the tower grounding information a couple of times to
CS> absorb all the information but after reading it, it made logical
CS> sense. I too am about to put up a 112' tower and have changed my
CS> plans for grounding & ground rods significantly based on the data.
CS> 73's from.......
CS> R. Otto
CS> N8NGA@one.net
CS> Cincinnati, Ohio
CS> **********************************************
CS> DXCC 10M ** DX is !! ** WAS 10M
CS> There is a very fine line between
CS> "HOBBY" and "MENTAL ILLNESS"
CS> **********************************************
CS> When trouble arises and things look really bad,
CS> there is always one individual who perceives a
CS> solution and is willing to take command.
CS> VERY OFTEN THAT PERSON IS CRAZY!
CS> **********************************************
CS> Thursday, August 31, 2000, 10:20:57 AM, you wrote:
BC>> On 8/30/00 6:36 PM, R. Otto at N8NGA@one.net wrote:
>>>
>>>Hello Bill,
>>>
>>>Couple of things for you to consider. First, most communities that
>>>have building inspection departments will want to see the cage
>>>requirements spelled out on a drawing -- signed by an engineer.
BC>> In Gwinnett County, GA, amatuer radio towers less than 50 feet do not
BC>> require any drawings or plans. Mine will be about 49 feet, including
BC>> mast.
>>>The cage should be
>>>suspended in the hole with wire to insure it's positioned properly
>>>when the concrete is poured. In the finished product, the cage
>>>usually isn't any closer than 3" from an outside concrete surface, and
>>>the cage is uniformly laid within the space, often on 12" centers.
BC>> Excellent, that's the information I needed.
>>>Lastly, you should read Polyphaser's report on tower grounding.
BC>> I visited their site yesterday and downloaded three PDFs on grounding. I
BC>> haven't yet read them, but I will. I found this information searching
CS> the
BC>> TowerTalk archives.
>>>A) It is advisable to use the rebar cage as PART (not all) of a grounding
>>>system.
BC>> UFER ground. I've heard about it before, and I got the PolyPhaser report
BC>> on it.
>>>C) Part of the grounding system should be a Ufer ground, which is
>>>made by placing copper wire in a pattern about 3" from the base of the
>>>concrete and tieing it to the tower legs. More on that in the
>>>Polyphaser publication.
BC>> Got it.
>>>D) Lastly, go to that publication as well to find out how to place
>>>your ground rods for the tower. I read many comments recently on this
>>>list that are in conflict with what Polyphaser says. A general
>>>guideline might be that if you use an 8' ground rod, you should have
>>>three rods, one on each leg of the tower - 8' from the tower, and each
CS> ground
>>>rod should be no less than 16' (double the length) from each other.
>>>They give a very detailed explanation on how to calculate what you
>>>need and how to set it up correctly.
BC>> I had planned 6 10' rods -- three close to the base, and three more
CS> some
BC>> distance away.
>>>E) Don't bother to call your building inspector to inspect the
>>>base..........who needs that headache.
BC>> Not me. I'm doing this "by the book." I want all the approvals that are
BC>> required.
>>>F) Attach one ground line to a tower leg and put three ground rods on
>>>that line.
BC>> I don't know if my ground setup will come to PolyPhaser's demanding
BC>> standards, but it certainly will be better than this.
>>>All kidding aside, there are many more good, constructive things that
>>>can/might be done, and I'm sure many of the Elmers here will suggest
>>>lots of them. It's up to you how much effort you want to invest
>>>in doing your tower right. Hope this helps.
BC>> Thanks, I appreciate it. Good advise.
BC>> Bill Coleman, AA4LR, PP-ASEL Mail: aa4lr@atlnet.com
BC>> Quote: "Boot, you transistorized tormentor! Boot!"
BC>> -- Archibald Asparagus, VeggieTales
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