INSTALLATION
2-3
September 1994
Part No. 001-2008-300
Secondary protection (other than grounding) pro-
vides the equipment protection against line transients
that result from lightning. There are two types of sec-
ondary protection, RF and Telephone Line.
RF
An RF protector keeps any lightning strike to the
antenna feed line or tower from damaging the Univer-
sal Stations. Install this protection in-line with the
combiner and antenna feed line.
RF protectors are selected by calculating the
maximum instantaneous voltage at the output of the
combiner. Do this by using the following equation.
V
P
= 1.414 (X) (
√
P(50)
where:
V
P
= Voltage at the output of the combiner.
P = Universal Station output in watts
X=
for
VSWR=
1.05
1.10 : 1
1.09
1.20 : 1
1.13
1.30 : 1
1.17
1.40 : 1
1.20
1.50 : 1
1.30
1.86 : 1
Example: Universal Station power output of 60W
with a VSWR of 1.3 : 1 (for this VSWR, X = 1.13):
V
P
= 1.414 (1.13) (
√
60(50)
V
P
= 1.59782 (
√
60(50)
V
P
= 1.59782 (54.772256)
V
P
= 87.52V
Telephone Line
There are four types of protection suppressors for
telephone lines; Gas Tube, Silicon Avalanche Diode,
Metal Oxide Varistor and Hybrid.
The hybrid protector is ideal for E.F. Johnson
equipment, and is strongly recommended. A hybrid
suppressor combines several forms of protection not
available in just one type of device. For example, a
high-speed diode reacts first clamping a voltage strike
within 10 ns, a heavy duty heat coil reacts next to
reduce the remainder of the current surge, and a high-
powered three-element gas tube fires, grounding Tip
and Ring.
2.6.1 PROTECTION GUIDELINES
Follow these guidelines for grounding and light-
ning protection. Each Universal Station installation
site is different; all guidelines may not apply to a
given situation.
Ground connections are a good metal-to-metal
ground (grounding rod, grounding tray, metal con-
duit) using #6 gauge solid wire or braided wire
straps.
With surge protectors, ground wires go directly to
ground, not through other equipment.
Run the ground wire for RF coax protectors directly
to ground.
With coax protectors, maximum instantaneous volt-
age does not exceed the rated voltage.
Do not run ground wires parallel to any other wiring
except other ground wires (a ground wire parallel to
a telephone line).
Double check all necessary equipment for good
ground and that all connections are secure.
2.7 UNPACKING AND INSPECTION
E.F. Johnson ships the Universal Station securely
crated for transportation. When the Universal Station
arrives, ensure the crates remain upright, especially if
storing the crates temporarily.
When unpacking the Universal Station, check for
any visible damage or problems caused by shipping.
If there is obvious damage from shipping mishaps, file
claims with the carrier. If there appears to be any
damage caused before shipping, file a claim with E.F.
Johnson. Contact Customer Service for assistance
(see Section 1.6).
If everything appears undamaged, remove the
Universal Station equipment from the crate, using nor-
mal precautions for unpacking.
