WaveRider LMS4000, User Manual

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3 Detailed Description
APCD-LM043-4.0 17
Cavity Filters
WaveRider recommends the use of cavity filters with all CCUs and is mandatory if colocated
with other CCUs. Cavity filters help to isolate the CCU from inband interferers, such as
colocated CCUs or non-WaveRider ISM band equipment, as well as out-of-band interferers,
such as cellular base stations and paging transmitters.
Lightning Arrestors
Since the CCU antenna is mounted outdoors, lightning arrestors are required with all CCU
installations. Lightning arrestors divert most of the energy from a lightning strike away from the
RF transmission line and equipment, to a bonded ground point. The lightning arrestor is
installed in series with the RF transmission line, as close as possible to the point where the
transmission line enters the building.
Transmission Line
A good quality RF transmission line should always be used to connect the CCU to the
antenna. “Good quality RF transmission line” means one that is weather resistant and UV-
protected, and that has low attenuation characteristics. All connectors in the transmission line
should be wrapped to prevent water penetration. Connecting the CCU to the transmission line
requires RF jumper cables, available from WaveRider.
Antenna
Each active CCU requires its own antenna. Antennas can be omnidirectional or have a
sectored beam pattern (for example, 180, 120, or 90 degrees). The choice of antenna is be
based on site and RF engineering considerations, and FCC and Industry Canada guidelines,
which are summarized in
Appendix D on page 185 .
Ethernet Switch
An Ethernet switch is required at the CAP if it is provisioned with more than one CCU, or to
interface with certain types of backhaul equipment.
3.2.2 Optional Components
The following Communications Access Point components are optional:
• RFSM
• RF Distribution Panel
RFSM
The optional RFSM (RF Switch Matrix), shown in Figure 10 , is required if CCU redundancy is
provisioned. The RFSM monitors the health of the operating CCUs. If a CCU fails, the RFSM
switches to a provisioned backup CCU, which is automatically programmed with the same