User's Manual

4 Commissioning
Page 29
4.3. CONNECTION OF THE ANTENNA CABLES
The remote unit has N-type antenna connectors. For its location, please refer to
chapter 4.2.2 Cabling and Connections. For mounting the cable connectors, it is
recommended to refer to the corresponding documentation of the connector
manufacturer. The bending radius of the antenna cables must remain within the
given specifications.
For the selection of cable and antenna it should be considered that, on the one hand,
a cable with higher loss is less expensive but, on the other hand, it impairs
performance.
It is sufficient to tighten the N-antenna connectors hand-tight. The use
of a tool (like pliers) may cause damage to the connector and, therefore,
lead to a malfunctioning of the remote unit.
4.4. OPTICAL-FIBRE-CABLE CONNECTION – RULES
Optical signals are transmitted by use of optical fibres. When connecting these fibres
observe the following instructions.
) Note: Care should be taken when connecting and disconnecting
fibre-optic cables. Scratches and dust significantly affect system
performance and may permanently damage the connector. Always
use protective caps on fibre-optic connectors not in use.
In general, optical fibres do not need special protective measures. However,
protection against environmental influences e.g. rodents and humidity must be
considered.
The optical fibre is a single-mode fibre. Type is E9/125 µm with the following
minimum requirements.
Attenuation: <0.36 dB / km @ 1310 nm / <0.26 dB / km @ 1550 nm
Dispersion: <3.5 ps / nm km @ 1310 nm / <18.0 ps / nm km @ 1550 nm
The specified bending radius of the optical fibres must not be exceeded. The pigtails
for the connection between master and remote unit must have a sufficient length. A
protection for the feeding into units must be given.
System attenuation and attenuation of optical components must be determined. This
can be achieved by measuring attenuation and reflection with an appropriate
measuring instrument. For pigtails, a total value of < 0.4 dB (measured to a reference
plug) can be assumed due to the dead zone of the reflectometer. These
measurements must be made with a sufficient length of optical fibre, at the input and
output of the device which has to be measured.