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Big Bird sitting (setting?) among the freshly pulled radials |
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More Big Bird. |
The dark area is an area built up with hot mix. There had been a
concrete wall on this side of the wash pad as well. The hot mix made a
much smoother
transition from the pad to the parking lot. |
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The radials are visible on top of the asphalt. |
We marked the end point of each radial with a paint dot and then
drove a long concrete nail to secure the radial end. The radials were
then pulled by hand to the nail and secured to it. Any areas of the
radials that were suspended above the asphalt were stapled down with
long fence staples. |
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The tower was setting on an old concrete wash pad. This is a
retaining wall on the uphill side. The radials run up to and over the
wall. |
Treated 2x4's were screwed into the wall to keep the radials tight. |
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The other side of the wall. Treated 2x4's was used to keep the radials tight over the wall. |
The wall and radials were later sprayed with tar to hide the nice shiny copper. |
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The white dots in the lower center of this frame are the radial ends.
The posts in the background are for a fence around the guy anchor
point. |
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The tower base grounding. |
Lightning concerns prompted the client to require 12 ground rods
driven around the tower base. One of the temp helpers is clamping the
2in strap to the main 8in strap ring. We use this setup when installing
copper screen. The radials are installed first and bonded to the OUTER
couple inches of the 8in strap. Then the screen is laid down and
bonded onto the INNER few inches. More on that later. |
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A site requirement was to ground the guy wires for personal safety. |
The row of 6 rods accomplished this. AM guy wires are broken
numerous times with
insulators. The grounding above only grounded the bottom 20ft of each
guy. A lighting consultant from the City of Atlanta required this
elaborate grounding scheme to give the workers a warm and fuzzy feeling.
For this AM tower, a single rod would have been
adequate. |
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Another view of the guy grounding and the short radials required by the cities lightning expert. |
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Close up of the exothermic bond to the rod. |
We used a CadWeld product called "One Shot" for these connections.
The One Shot product is a one time use ceramic mold that is great for
wire to rod connections. The mold is inserted onto the wire and then
onto the rod. The weld metal is poured in (not forgetting the metal
disk lest you have an explosion of profanity when the weld metal falls
thru the mold onto the ground), light it off and when cool the mold is
simply broken with a tap from a hammer. This complete shot costs just
slightly more than the just the weld metal for the large reusable molds
(which we also use). |
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Side view of the screen and radials running off of the concrete pad. |
The ding in the HVAC unit was the result of a conflict between the HVAC unit and a backhoe.
HVAC 0, Backhoe1 |
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The screen with 4 inch strap around perimeter. |
The screen with 4 inch strap around perimeter. The radials were bonded to the 8in main ground and the 4in perimeter strap.. |
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Close up view of the tower base grounding. |
This view shows the intricate copper work. We use .020x2in copper to
bond the 8x24ft sections of the copper screen together. Even if a
portion of the screen is damaged, the strap will allow the remainder to
function normally. Most of the ground systems I have inspected over the
years has had damage to the screen. Most ground system installers (not
that there are very may of us now) simply wrap the edge's of the
sections together and some even connect the radials to the outside edge
of the screen. I have repaired MANY ground systems that used this
scheme and have found it to be very unreliable. Visible in the
background is a length of 4in strap that will be use to bond the large
ATU into the system. |
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Close-up of base ground ring. |
The radials are bonded to the outside of the large strap and the screen is bonded to the inside. |
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Huge candelabras. |
Not really relevant to the WSWK site except they were visible toward Buckhead from the site. |
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More tower base grounding. |
The building perimeter strap and the pier top grounding is visible
here. Not visible is the copper strap directly grounding the lower side
of the arc gap. |
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One of the 12ea 2in ground rod straps. |
The 2in strap was exothermically bonded to the strap using Harger
UltraWeld molds and materials. The strap was then brazed to the main
tower base ground ring. |
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Jeremy (back left) slacking off while the temp guy (right front) works hard. |
Also visible here are several of the 2in ground rod straps before they were
trimmed. |
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Jeremy still slacking, the temp still working. |
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Looking basically north toward the back corner of the lot. The
trailer visible in the background is used to transport AGSC equipment. |
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The JD 4600 in the background is our main ground system installation machine. |
At this job it was nothing more than a very expensive reel holder. |
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The lot with radials visible. |
The paving company posted a guard at the site every night to keep an
eye on the nice shiny copper. It was their miscalculation that left the
copper exposed. They were perpetually late or no show. They did good
work but the foreman had no concept of time. His OR ours. |
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A close-up of a radial wrapped around a concrete nail at it's terminus. | | |