IBUC Operation Manual
Terrasat Communications Inc.
Rev. A
4-13
moisture for 15 to 30 days after rain or snow melt. Concrete absorbs moisture quickly,
yet retains moisture for a period of time. The concrete’s large volume and great area of
contact with the surrounding soil allows a good transfer to the ground.
In the concrete base, an Ufer ground can be established by running a #4 gauge solid
wire or rebar and connecting with pigtails to the base of the pedestal.
The Ufer ground is only one step in proper grounding. The Ufer ground should be
augmented with coupled pairs of 10 foot (3.05m) rods, placed 20 feet (6.1m) into the
ground, spaced 20 feet (6.1m) apart. The first rod should be placed close to the
antenna. The second rod should be placed towards the equipment enclosure. A #2
gauge wire should connect the rods and antenna mount. A ground rod should be
placed at the equipment enclosure as well. If it is virtually impossible to install the
ground rods, then radials are needed. This can be accomplished by laying 10 or more
lengths of 1 1/2-inch (3.81cm) copper strap, at least 50-feet (15.24m) long, in a radial
fashion around the antenna base. The straps should be buried, if possible. The hub
must be interconnected to the utility ground.
The ground configuration can vary from one location to another. It is best to measure
the soil conductivity and design a 5 ohm ground system. To protect the system from a
direct strike, a lightning rod placed 2 feet (61 cm) higher than the highest point of the
dish should be interconnected to the Ufer ground with #2 gauge copper wire.
IBUC / PSUI Grounding Recommendations
Grounding and lightning protection is recommended as follows.
Cable Shielding: The shield currents can be eliminated with proper techniques. A
grounding strap at the end of the coaxial and data cables should be connected to the
ground lug at the antenna base with a #4 gauge copper wire. This provides a path of
least resistance prior to entering the electronic equipment.
AC: The best way to protect the equipment is to have two protectors. The first is the
power mains protector that is mounted directly across the mains in the breaker box.
The second should be mounted or grounded directly at the base or hub of the antenna
or at the 19 inch rack.
Data and Control Lines: The I/O lines can deliver surge current to the equipment and
should be protected as well.
Electrical grounding: Grounding of the IBUC and PSU units is recommended to prevent
possible damage from lightning and/or other induced electrical surges. It is
recommended that 3/0 or 4/0 AWG (American Wire Gauge) stranded copper wire be
used to bond the IBUC and the PSU to the earth ground (grounding rod), using the most
direct (shortest) route.
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