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
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|