Hi again Rob,
Yes the ideal location for your coax lines to come in would be the same
place that your power panel is located. But in your case it is not
practical. The next best thing is to run the power for your shack over
to where the coax line bulkhead panel is.
The bulkhead panel is your single point ground position. All of the
power for your shack equipment comes from it. All of your antenna
connections come from it. Your tower ground should also be tied to it.
You should have as extensive a ground (many ground rods and radials) as
you can manage tied directly to your bulkhead panel with the shortest
leads possible. Run them separately to the bulkhead panel. Don't make a
common connection of several ground rods outside and then run a single
wire to the bulkhead panel. You will have a much lower impedance ground
system if each ground line runs directly to the panel.
You hook the green ground wire from your house power that you run over
to the bulkhead panel to it but not the neutral. It must float as it
does everywhere else. The bulkhead panel is treated the same as an
electrical sub panel would be as far as grounding goes. But your power
protection devices (mov's and or gas tubes) would go from hot to ground
and neutral to ground at the bulkhead panel.
By the way polyphaser makes an outlet box with protection devices in it
and a cord on it to plug into a distant outlet. The outlet box is to be
mounted right on your bulkhead panel along with the coax protectors and
serves to do exactly as I described above.
This is what a "single point ground" is. ALL connections go directly to
it. You can have as many grounds connected to the bulkhead panel as
desired going to all sorts of other places. But do not ground the rig to
any place other than the bulkhead. And don't connect the rig to any
cable not coming from the bulkhead panel.
To be legal as far as NEC goes you should also run a ground wire outside
from your bulkhead panel to your electrical entrance panel ground rod on
the other side of the house. With that kind of distance it is going to
do little as far as lightning is concerned but it does keep it at the
same potential as far as power frequencies and dc are concerned.
Due to the long distance between your bulkhead entrance panel and your
power entrance panel is the reason you need the power protection devices
at the bulkhead. You want no difference in potential at all among any
lines going to your rigs.
In your case a whole house protector would be good to also install at
the power entrance panel. That will help reduce any strike energy coming
in on the power line.
But your lightning protection for your rig will take place at your
bulkhead panel.
If you got your power from an existing outlet for the rigs you would
have a considerable distance between the power ground and your coax
grounds. The rig would be in the middle.
By the way did I also mention that the tower should have its own
extensive ground system right at the tower too?
Hope that helps.
73
Gary K4FMX
Rob Atkinson, K5UJ wrote:
> okay Gary, i'm going to be the stupid one and say that there seems to be
> contradictions in what you advise.
>
> let's say i have my service entrance, its ground rod and panels, on one
> end of the basement. the feedline bulkhead is on the other side of
> the basement. it sounds like you are advising that i run a shack
> service circuit across the basement and ground it to the feedline
> bulkhead which is bonded to the shack cabinets and a rod or rods
> outside. The circuit, 60A let's say, would branch out to outlet
> boxes. this does not sound like a SPG in the conventional sense I've
> been led understand. it might be okay with a large copper strap below
> grade outside connecting the service panel ground rod and running all
> the way around to the feed bulkhead rod. otherwise it sounds like a
> double point ground. i have always been told that you MUST have
> everything--satellite, cable, tv antennas, phone, AC service, antenna
> feedlines, and in-laws coming in at the exact same grounded location so
> everything will be colocated and rise to the same potential. tnx for
> ur patience
>
> rob/k5uj
>
>
> From: Gary Schafer <garyschafer@comcast.net>
> Reply-To: garyschafer@comcast.net
> To: "Rob Atkinson, K5UJ" <k5uj@hotmail.com>
> CC: towertalk@contesting.com
> Subject: Re: [TowerTalk] grounding
> Date: Sun, 09 Oct 2005 12:16:48 -0400
>
>
>
> Rob Atkinson, K5UJ wrote:
>
>> i'll try this again. my computer went nuts in the middle of writing
>> this before, and i had to reboot it.
>>
>> Gary, let me make sure i understand this:
>>
>> <<<For example, it is not necessary to have the mains power coming in
>> the same place as the coax lines. Just run a power line from a
>> convenient place over the where you have your antenna entrance panel.
>> Put your power line protectors there. Now run ALL your shack equipment
>> from that one power point.>>>
>>
>> do you mean run a shack service line around outside from where the
>> drop and kwh meter are, to where the feedlines enter?
>>
>> rob/k5uj
>>
>
> Hi Rob,
>
> Run it anywhere that you have access. It doesn't need to be outside.
> The point is that you do your grounding and power protection at the
> entrance panel for your antennas. The cable entrance panel is your
> single point ground. You have no other path to your equipment but
> through that panel.
> Now an extensive ground system hooked to that panel would be ideal.
>
> 73
> Gary K4FMX
>
> _________________________________________________________________
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>
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