5. CONSIDERATIONS FOR LONG CABLE
RUNS
5.1.
Due to process variations in the fabrica-
tion of the HP58516A, the gain through the
device can vary fi-om
+3
dB
to -3
dB.
Assume
the worst case loss of the HP58516A when
determining if line amplifiers are necessary
in
your GPS antenna system.
5.2.
The assumed worst case loss through the
HP58516Ais equal to:
18meters (60
R)
of cablelength when
using
LMR
400 cable
8 meters (25
ft)
of cable lengthwhen
us-
ing
RG-213cable.
5.3.
Use this procedure to determine
if
line
amplifiers arerequired:
1. First, calculate the distance fi-om the an-
te~ato themost distant receiver.
2. Add the assumed worst case loss through
the HP 58516A
in
terms of cablelength.
3. Compare theresult to the requirements
for line amplifiers below. Ifline amplifi-
ers are required, they should be added as
closeto the GPS antenna aspossible
(within
10meters133feet).
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
theHP 58516A):
Less than 115meters(377feet),no line
amplifierisnecessary.
More than 115meters (377feet)and less
than240 meters (787feet),you need
1
line amplifier.
More
than
240 meters (787feet)and less
than 360 meters (1181feet),you need
2
line amplifiers.
More than 360 meters (1181feet),contact
HPfor 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 53meters (174feet),no line
amplifier
is
necessary.
More than 53meters (174feet)and less
than 105meters (345feet),you need
1
line amplifier.
More than 105meters (345feet)and less
than
158meters (518feet), you need
2
line amplifiers.
More than 158meters (518feet),contact
HPfor assistance.
7.
INSTALLATION
7.1.
This section provides information on
mounting the distribution amplifier.
PartsRequired
7.2.
Having the items listed below on hand
will help savetime duringinstallation.
Customer Supplied:
-
If the distribution amplifier
will
be
mounted
to
a surface,
a
mounting
bracket isneeded. Option AUB pro-
vides
a
mounting bracket and 4
screws. Otherwise, order
(1)
HPp/n
58516-00002 (mountingbracket)
AND
(4)p/n 0515-0372 (screws).
-
Use fastenersno larger than
6.35 mm (0.25
in)
diameterwith the
mounting bracket.
Tools Required
TORX T-10 screwdriver for bracket
screws.
Drill
andbits asrequired if you intend to
mount the amplifier to a surface.
