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5. CONSIDERATIONS FOR LONG CABLE
RUNS
5.1.
Due to process variations in the fabrica-
tion of the HP 58516A, the gain through the
device can vary fi-om +3 dB to -3 dB. Assume
the worst case loss of the HP 58516A when
determining if line amplifiers are necessary in
your GPS antenna system.
5.2. The assumed worst case loss through the
HP 58516A is equal to:
18 meters (60
R)
of cable length when
using
LMR
400 cable
8 meters (25 ft) of cable length when us-
ing RG-213 cable.
5.3.
Use this procedure to determine if line
amplifiers are required:
1. First, calculate the distance fi-om the an-
t e ~ a to the most distant receiver.
2. Add the assumed worst case loss through
the HP 58516A in terms of cable length.
3. Compare the result to the requirements
for line amplifiers below. If line amplifi-
ers are required, they should be added as
close to the GPS antenna as possible
(within
10 meters133 feet).
6. REQUIREMENTS FOR LINE AMPLIFIERS
6.1.
This section provides information that
will help you determine if line amplifiers are
required for your GPS antenna system instal-
lation.
For LMR 400 cable:
6.2. If the estimated cable length between the
antenna and the most distant GPS receiver is
(include the assumed worst case loss through
the HP 58516A):
Less than 115 meters (377 feet), no line
amplifier is necessary.
More than 115 meters (377 feet) and less
than 240 meters (787 feet), you need 1
line amplifier.
More than 240 meters (787 feet) and less
than 360 meters (1181 feet), you need 2
line amplifiers.
More than 360 meters (1181 feet), contact
HP for assistance.
For RG-213 cable:
6.3.
If the estimated cable length between the
antenna and the most distant GPS receiver is
(include the assumed worst case loss through
the HP 58516A):
Less than 53 meters (174 feet), no line
amplifier is necessary.
More than 53 meters (174 feet) and less
than 105 meters (345 feet), you need 1
line amplifier.
More than 105 meters (345 feet) and less
than 158 meters (518 feet), you need 2
line amplifiers.
More than 158 meters (518 feet), contact
HP for assistance.
7. INSTALLATION
7.1. This section provides information on
mounting the distribution amplifier.
Parts Required
7.2. Having the items listed below on hand
will help save time during installation.
Customer Supplied:
-
If the distribution amplifier will be
mounted
to
a surface, a mounting
bracket is needed. Option AUB pro-
vides a mounting bracket and 4
screws. Otherwise, order (1) HP p/n
58516-00002 (mounting bracket)
AND
(4) p/n 0515-0372 (screws).
-
Use fasteners no larger than
6.35 mm (0.25 in) diameter with the
mounting bracket.
Tools Required
TORX T-10 screwdriver for bracket
screws.
Drill and bits as required if you intend to
mount the amplifier to a surface.
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