User's Manual Part 1

20 APCD-LM043-8.0 (DRAFT C)
3: Detailed Description
Cavity Filters
WaveRider recommends the use of cavity filters with all CCUs and is mandatory if co-located
with other CCUs. Cavity filters help to isolate the CCU from inband interferers, such as co-
located 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 based
on site and RF engineering considerations, and FCC and Industry Canada guidelines, which
are summarized in Appendix F on page 229.
Ethernet Port
The CCU has one 10BaseT Ethernet port.
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.
Any DC voltage applied to the Ethernet port may damage the CCU, the Ethernet
cable, and/or network gear. The CCU is not
a Power-over-Ethernet device.
3.1.3 Network Access Point (NAP)
The NAP provides the Internet connection point for one or more CAPs. An LMS4000 system
can have more than one NAP. The number of NAPs depends on the geographical layout of
the LMS4000 system and the location of available Internet access points. A single NAP can
provide Internet connection for one CAP, or several CAPs, each either co-located with the
NAP or connected to the NAP over backhaul facilities.The following sections discuss the
operation of the LMS4000 900 MHz Radio Network, of which the CCU and EUM are the key
components.