Thread: Single ground
View Single Post
  #3   Report Post  
Old November 19th 04, 01:10 AM
Gary Schafer
 
Posts: n/a
Default

Bill,

I would reroute the wire from your electrical panel directly to the
ground rod just outside your entry. Then from there run a single line
to your rig. This keeps the rig out of the middle of the ground
connections. If possible your AC line for the rig should run from
where that ground rod is. AC protectors should be put at that point
along with the coax protectors. Now you have a single point ground
system and the rig is not in the middle of things. All grounds are at
one point including all your protectors.

As far as the control wires, get some large MOV's and place one on
each line to ground. Again at your single ground point where your
ground rod is at the entrance.

With several control lines any surge energy that comes down them will
be shared by all. You can get by without gas tubes in this situation
as all those MOV's are effectively in parallel.

If you look inside a rotator protector like Polyphaser makes that is
all you will find in them.

The ground connection from your protection devices to your ground rod
should be as short and as large as you can manage. 3" wide copper
strap if the distance is a few feet. If it is a little longer run
place two copper straps edge to edge in parallel or a 6" strap.

It is important to have a low resistance / low inductance path to your
ground system. In addition you may want to add more ground rods /
radials to your entrance ground. Even just buried radials run out in
different directions away from that single ground rod that you have
will help lots. Placing an additional ground rod at the end of each is
still better. The big thing is to run the radials in different
directions to get some space between your ground rods. Ideally the
distance between rods should be the sum of their lengths.
The ground saturates when trying to dissipate energy in one place.
Spreading it out increases the amount of energy you can dump in a
given amount of time.

73
Gary K4FMX


On Thu, 18 Nov 2004 22:51:40 GMT, "Bill Ogden"
wrote:

In almost 45 years of ham operation I have never bothered with a "good"
ground connection. I am in what might be my last location and now have a
"real" tower (55' crank up). I understand the principles behind a single
ground, or at least I think I do. However, ideal requirements (as often
quoted in various codes and standards manuals) need to be matched with what
one can actually do.

I have several ground rods by the tower and one by the entry to my basement
shack. The tower-to-entry-point has two #10 wires in the trench (but not
not in the conduit) that connect the nearest of the tower ground rods to the
entry-point rod. The distance is about 45'.

From the entry point area to the rig is about 10' and has a single #10 wire.
Also from the rig area to the electrical panel is another #10 wire that is
about 40'.

Is this a reasonable arrangement? Is it better than nothing? Worse than
nothing?

I will shortly place two ICE units at the entry point on the two coax lines
from the tower. I am still considering what to do with the control
lines --- there are 12 for a SteppIR, 6 for a rotator, and 6 for a remote
coax switch.

Bill
W2WO