Microsemi SyncServer S300 User Manual page 146

Tasks
unobstructed view of the sky and thus be mounted on a roof, or in some cases in a window.
GPS provides almost continuous operation day and night, and under poor weather con-
ditions.
Since the GPS signal is very weak, the antenna amplifies the signal to drive it through the
cable to the receiver. Antenna cable however offers some resistance and the GPS signal
strength will attenuate as it travels down the cable. GPS receiver sensitivity is finite so if the
cable length is too long the signal will be too weak for the receiver to detect it. Consequently it
is very important to know the distance in advance between the antenna and the receiver so
that the proper cable solution can be installed.
Antenna cabling solutions typically vary depending on how far the antenna is installed from
the GPS receiver. The unaided cable length limit for the SyncServer is 150 feet (45 m).
Adding a GPS inline amplifier extends the cable length an additional 150 feet (45 m) to a total
of 300 feet. Beyond 300 feet (90 m) alternative methods may be used. The following figure
highlights the cable lengths and the antenna solutions that enable them:
Cable lengths and
antenna solutions
In-line Amplifier: In-line amplifiers overcome signal attenuation by amplifying the GPS signal,
allowing an additional 150 feet (45 m) of cable, to a total of 300 feet. The inline amplifier
attaches directly in line with the antenna cable near the antenna and uses the same power
as the antenna; no extra wiring is required. Mounting the amplifier inside the mounting mast
helps protect it from moisture and exposure to the elements. See the following figure of a typ-
ical mast mount application:
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