Distance Between Antenna And Receiver - Microsemi SyncServer S200 User Manual

Review the GPS topics in this user guide
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Troubleshoot for issues with the GPS antenna and cable.
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Contact Microsemi Customer Assistance (on page 3).
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Distance Between Antenna and Receiver

GPS satellites signals operate in the L1 band (1575.42 MHz). Practically speaking the
antenna must have an unobstructed view of the sky and thus be mounted on a roof, or in
some cases in a window. GPS provides continuous operation day and night.
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. Antenna cable runs are supported from the standard 50 ft (15m) to over
1500 ft. (457 m). 150 feet (45 m) is the unaided cable length limit for many GPS timing receiv-
ers from Microsemi.
Adding a GPS inline amplifier extends the cable length an additional 150 feet (45 m) up to a
total of up to 300 ft. (90 m). The inline amplifier installs in-line with the antenna cable, using
the existing antenna power. No extra wiring is required.
The GPS Down/Up converter makes cable runs of 250 to 1500 feet (75 m to 457 m) possible
using a special GPS antenna that converts the signal to a lower frequency less susceptible to
attenuation, and transmitting it the length of the cable, powered by an external power supply.
An external power supply is provided with the GPS Down/Up converter.
The following diagram gives a summary of the cabling solutions for different distances
between the antenna and receiver. For more specific cabling information see Cabling
between the receiver and antenna:
Cable lengths and antenna solutions
997-01520-02 Rev. G2..........................................................................
Installation Guide
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