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Re: [TowerTalk] A unique and difficult grounding problem

To: towertalk@contesting.com
Subject: Re: [TowerTalk] A unique and difficult grounding problem
From: "Roger (K8RI) on TT" <K8RI-on-TowerTalk@tm.net>
Date: Sat, 06 Jun 2015 00:33:16 -0400
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
There is a problem with the best approach. I agree with it in principle, but In over half, ...well over half the installations I've seen in over 54 years as a ham the best approach is not practical, either from a logistics, and or cost approach.

My house is typical for almost all homes in this area with the electrical, phone and cable coming in the front while the antennas come in from the back.

The garage apron which is nearly 30 feet wide by 20 feet long prevents the installation of a ground ring with the shortest route to the entrance being under the 30 feet of concrete, with the available route being 110 feet longer.
The best antenna entrance is almost opposite the power entrance

I haven't been able to find a way around this.

To make things worse, I operate SO2R with one station in the shop and one in the house. They are adjacent, but different addresses and different power feeds from the same transformer. The neighbor across the road is also on the same transformer. As the antenna system is common to both stations, that makes the tower system grounds common to both stations resulting in both panel grounds eventually being tied together. I've not seen any practical way to avoid this.

73

Roger (K8RI)


On 6/5/2015 2:39 PM, Joe Subich, W4TV wrote:

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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--

73

Roger (K8RI)


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