One clarification the the below statements. The "single point ground" often
gets misused in these discussions. A single point ground is NOT a place or
spot in the earth but it is a point of common connection which can be
anywhere designated.
In the description below the single point ground should be the panel where
the arrestors are mounted. ALL suppressors should be mounted directly to
this single panel. You don't want multiple panels with separate ground rods
to handle this function.
This includes coax cable suppressors, rotor line suppressors and power line
suppressors for power that feeds the equipment in your shack. They all need
to be on the same (heavy) panel. Then ground straps are run from this single
point ground panel to the ground system which should be located as close as
possible.
The whole idea of a single point ground is to have a place to tie all lines
together with zero impedance between them. You can run as many grounds to
earth from that point as you desire. But all cables entering the shack must
be physically mounted to that single point ground panel.
73
Gary K4FMX
> -----Original Message-----
> From: towertalk-bounces@contesting.com [mailto:towertalk-
> bounces@contesting.com] On Behalf Of Phil Camera
> Sent: Friday, January 05, 2007 10:56 AM
> To: towertalk@contesting.com
> Subject: [TowerTalk] Antenna/Tower Grounding (Lightning Protection)
>
> Even though a search through the archives will reveal the same
> information, many times over the past number of years (at mulitple times
> per each year), I'll state my understanding of the good practices and also
> what I have for my system.
>
> To me there are 5 parts to a well designed grounding system.
>
> 1. Tower ground
> 2. Cable ground
> 3. SPG
> 4. Shack ground
> 5. Electric service ground
>
> 1. Polyphaser recommends a ground radial wire (I use #4 bare solid) for
> each tower leg and 50 - 75 ft long from each leg with ground rods spaced
> every 2X their height. Also is the tower is somewhat close to the SPG,
> then a wire from any leg radial should be run and connected to that.
>
> 2. Coax shields should at least be connected to the tower at the base and
> somewhat optional if you want to connect them at the top (I understand
> that I may have to replace the coax run up the tower.) ALL cables that
> enter the house should have arrestors located right at the entrance to the
> house and connected with a very short run to your SPG (single point
> ground). I mount my arrestors in Hoffman electrical boxes and actually
> have three rods spaced two feet apart since I have more than one boxes
> full of arrestors (lots of cables). This applies for rotator control,
> etc. Everything.
>
> 3. SPG kinda described above. For the poster who had all his cable
> entering underground, I've seen folks that had mounted their arrestors on
> a large copper panel inside on the foundation wall and then ran a large
> diameter (always solid never stranded and copper strips 2-4 inches wide
> are also OK) wire back outside to their SPG. If your cables come to the
> house overhead, then they should all drop to the ground to the arrestor
> boxes and SPG and then enter the house however you want, either at ground
> level or run back up to a 2nd floor shack.
>
> 4. All of your equipment should have their ground connections tied to a
> buss bar (I use a piece of 1/2 copper pipe mounted along the back of the
> desk, and then a large diameter (don't use braid) wire run outside to the
> SPG.
>
> 5. Run another wire outside (avoid sharp bends) the house and connect to
> the electrical service entrance ground rod. One can drive additional
> ground rods along this run.
>
> I use #4 bare solid wire. All outdoor connections are CadWelded (which is
> preferred over mechanical since no maintenance). I also use ICE
> (Industrial Communications Engineers) devices rather than PolyPhaser.
> This is what consitutes a properly designed and installed system. All
> parts must be in place as described or else Mother Nature may bite you.
>
> Oh, I guess there is a sixth part; good homeowner's insurance.
>
> Hope this helps.
>
> Phil KB9CRY
> _______________________________________________
>
>
>
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