I agree. The way things are shown in that picture is a poor way of
connecting to the ground rods.
I don't know why they would want to put a ring around the tower to connect
ground radials to. It only adds inductance by the extra length and bands
between the tower leg and the radial. Besides a ground ring there does
nothing but waste wire. Same with the ring (square) at the far end of the
radials. The potential between ground rods is going to be zero in the
circle. Any connection (ring) between them does nothing.
Radials should be run straight out from each tower leg which has a much
lower impedance than adding a ring.
Their ground lead from the tower leg has too much of a bend and does not go
directly to a ground rod.
It also looks like their buss bar in the building where the cables connect
is grounded by small parallel wires.
This needs to be right at the building entrance, low to the earth and a very
wide copper strap run to a ground system of several ground rods and radials.
No more than a couple of feet away.
Hard to tell as the picture may not show everything.
73
Gary K4FMX
> -----Original Message-----
> From: towertalk-bounces@contesting.com [mailto:towertalk-
> bounces@contesting.com] On Behalf Of Martin Sole
> Sent: Friday, March 25, 2011 10:16 PM
> To: 'K8RI on TT'; towertalk@contesting.com
> Subject: Re: [TowerTalk] Grounding Question
>
> I don't fully agree with the way it is shown on that picture. I would
> rather
> see the grounding wires taken straight down and the feeders swooped off
> to
> the side, observing minimum bend radius of course. Additionally keep the
> ground wires from the outer bonds to the ground plate junction less than
> 0.5m.
>
> Just my 2 satang worth.
>
> Martin, HS0ZED
>
>
> -----Original Message-----
> From: towertalk-bounces@contesting.com
> [mailto:towertalk-bounces@contesting.com] On Behalf Of K8RI on TT
> Sent: 26 March 2011 09:01
> To: towertalk@contesting.com
> Subject: Re: [TowerTalk] Grounding Question
>
> On 3/25/2011 9:25 PM, Jim W7RY wrote:
> > If you would like to see how the professionals do it, take a look
> here:
> >
> > http://www.maplenet-inc.com/grounding
>
> I really dislike that approach on the types of cables most of us use. It
> works well with solid copper jackets like Heliax (TM), but I'd not want
> to
> use it with regular coax using either a braid or foil shield. Also
> weather
> proofing these on braid and foil shields is much more critical than on a
> coax with a solid copper shield. I much prefer the use of bulkhead
> connectors for those grounding points which I do at the top and bottom
> of
> the tower.
>
> I do use the ring around the base of the tower and tie that into ground
> runs
> going out to about 80' from the tower.
>
> 73
>
> Roger (K8RI)
>
>
> > Motorola's Communications Site Ground Standards know as R56, are all
> > written around the NEC and TIA/EIA standards. As well as many MIL
> > documents. I happen to work for one of the authors.
> >
> > W8JI has some good stuff on station grounding. www.w8ji.com
> >
> > Do some Google searching on Motorola R56 or tower site grounding or
> > ham station grounding etc. You will find lots of info.
> >
> > 73
> > Jim W7RY
> > Motorola
> >
> >
> > --------------------------------------------------
> > From: "Jim Brown"<jim@audiosystemsgroup.com>
> > Sent: Friday, March 25, 2011 10:00 AM
> > To:<towertalk@contesting.com>
> > Subject: Re: [TowerTalk] Grounding Question
> >
> >> On 3/25/2011 6:08 AM, Larry Libsch wrote:
> >>> I must be misunderstanding something . How do I attach my coax
> >>> shield to the outside common point and also attach it to my radio
> >>> inside the shack?
> >> Since I wrote the grounding chapter for Steve's book, I'll attempt to
> >> clarify.
> >>
> >> One ancient and accepted method of accomplishing this is often called
> >> a "ground window," where coax cables go through lightning arrestors
> >> (Polyphaser, ICE, etc.) that are bonded to a conductive plate
> >> (usually
> >> copper) where they enter the building, and that plate is bonded to
> >> the ground system. The coax from the antenna has a PL259 that screws
> >> to the arrestor on the outside of the wall and a coax jumper with
> >> PL259s on both ends goes between the arrestor and the radio.
> >>
> >> Several brands of arrestors are sold in "feed-through" form, so that
> >> the plate can be installed in a wall (or an actual window). There's
> >> nothing magic about the feedthrough arrangement, it's just a
> >> mechanically neat way to do it.
> >>
> >> The MOST critical part of all of this is the bonding together of ALL
> >> grounds associated with your home and shack -- power service
> >> entrance, shack, CATV, telco, other lightning arrestors, building
> >> structure, all ground rods, etc.
> >>
> >> 73, Jim Brown K9YC
> >>
> >> _______________________________________________
> >>
> >>
> >>
> >> _______________________________________________
> >> TowerTalk mailing list
> >> TowerTalk@contesting.com
> >> http://lists.contesting.com/mailman/listinfo/towertalk
> >>
> >>
> >>
> >> -----
> >> No virus found in this message.
> >> Checked by AVG - www.avg.com
> >> Version: 10.0.1204 / Virus Database: 1498/3529 - Release Date:
> >> 03/25/11
> >>
> > _______________________________________________
> >
> >
> >
> > _______________________________________________
> > TowerTalk mailing list
> > TowerTalk@contesting.com
> > http://lists.contesting.com/mailman/listinfo/towertalk
> >
>
>
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|