The standard advice is to complete the ground "ring" around the house
- extending counterclockwise from the 6M entry point to the service
entrance. Then relocate the 4" underground conduit from the main tower
so it enters the shack at the same point as the 6M entry point.
The combined entry point then becomes the common point for all coax
and control line grounding - each line is connected where it crosses
the "ground ring".
The "ground ring" is about the only safe way to provide a common entry
when cables (or any conductor - e.g. air conditioning lines, well
power/control/water pipes, etc.) must enter/leave a building somewhere
other than the utility service entrance.
73,
... Joe, W4TV
On 2015-06-05 2:01 PM, Peter Dougherty (W2IRT) wrote:
Once again, hello all.
For 10 years I've wondered about the best way to ground my station. If I
just had one tower it would be easy. Likewise if all my feedlines entered at
the same place. But here this is not the case. I have two towers-a main
70-footer for HF and a 35 footer for 6m (and maybe someday a 10m Yagi as
well). The main tower is grounded via three 2" copper straps (and stainless
steel clamps) connected to 8' copper-clad steel ground rods at the tower's
base, and 4AWG solid bare copper wire Cadwelded to the rods and then out to
a ground radial field. The small tower will soon be connected to one end of
the ground field via strapping or braid.
*See the following images (an overall grounding plan and photos of both
cable entrance points):
http://i291.photobucket.com/albums/ll290/W2IRT/Ground%20Plan.jpg
http://i291.photobucket.com/albums/ll290/W2IRT/6m%20tower%20and%20inlet.jpg
http://i291.photobucket.com/albums/ll290/W2IRT/back-house1.jpg
The main tower's coaxes all connect to an Ameritron RCS-12L (8 ports,
equipped with lightning protection gas discharge tubes). The coaxes and
control lines enter the house via a 4-foot high crawlspace situated under
the radio room, traverse about 25' of carpeted floor then rise up to the
radio desk. The secondary tower's coax enters the house via an inlet box
above floor level in the shack, about 30 feet away from the main tower's
inlet, and on the other side of the shack's floor.
There *is* a Cadwelded, bonded ground line between the main tower, the inlet
box and the secondary tower but the problem I'm facing, and the question I'm
asking, is where the heck do I put the single-point ground panel? Bonding
everything so a lightning strike's rise and fall would occur simultaneously
is something.
---------------------------------------------
Peter, W2IRT
www.facebook.com/W2IRT
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