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The GPS10RBN GPS Disciplined, Rubidium Frequency
Standard is now in use all over the world. There
are over fifty different options for the product and
this page describes the fiber optic link for the GPS
antenna.
The standard model is supplied with an active GPS
antenna. Normally this is connected to the
GPS10RBN via coax cable. Up to 50 m of cable can
be used without the need of an GPS amplifier, when
HDF400 cable is used.
For longer runs, Precision Test Systems can supply GPS
amplifiers, allowing up to 250 meters of HDF400 coaxial
cable to be used.
However, sometime coaxial cable is not convenient.
Either because very long cable runs are needed or there
is a high risk of lightening. For lightening, we
can supply lightening arrestors. However, fiber
optic may be a better route in these cases.
Fiber optic cable is ideal where there are large amounts
of electromagnetic interference, or the equipment is
positioned in a tunnel or underground mine.
Option 35 for the GPS10RBN is a fiber optic link for the
antenna. Refer to the picture below.
The
option consists of an optical transmitter and an optical
receiver. The standard antenna supplied with the
GPS10RBN is connected to the optical transmitter.
The transmitter converts the GPS radio frequencies to
optical and feeds the optical signal down the fiber
optic cable. The transmitter also feed the 5V
required for the active antenna on the inner wire of the
antenna cable.
At
the equipment end the fiber optic cable is connected to
the optical receiver. This converts the signal
from an optical one back to the GPS radio signal and
this is fed to the GPS10RBN.
Because optical cable has such low loss, the cable run
can be up to 10 km.
This
option operates and both L1 and L2 frequencies and
typically have 0 dB loss. The optical wavelength
is 1310 nm and the fiber optic cable to be used is
singlemode 9/125, Corning SMF28 or equivalent.
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