User's Manual

302395 User’s Guide and Repeater Network Design Guide
6 February 2004
2.2 General Coverage Guidelines
Before designing a M/LC infrastructure, review the following general rules.
2.2.1 Locations, Repeater Quantities, and Antennas
Location Description
PITS
It is always desirable to have triple coverage inside of deep pits. Three repeaters
positioned around the edge at geographically different locations is recommended
(roughly 120 degrees apart). However, they also must have a clear line-of-sight to
other repeaters so there is a trade-off to be made between visibility to other
repeaters, and view of the pit. The vertical beamwidth of the antenna must be enough
to cover into the pit from the edge. Although a omni (or sector) antenna can be tilted
downward up to 10 degrees into the pit to aid in this endeavor, the other line-of-sight
repeaters must remain in the coverage pattern of the antenna (which would be tilted
up off the backside).
HAUL
ROADS
It is desirable to have right side and left side coverage although this is not always
possible.
REPEATERS
Ideally, each repeater would provide coverage over a selected area of the mine while
at the same time, having a view of at least two other “upstream” repeaters.
“Upstream” repeaters are access points that must be used in order to reach a hard-
wired bridge (or zero-hop) node. Minimizing the number of required “hops” is
important in order to maximize bandwidth (i.e. maximize the amount of traffic). The
more “zero-hop” (i.e. direct wired) repeaters that are available, the better the system
throughput will be.
SHOVELS
Shovels are the most difficult area to cover. That is why M/LC shovel systems have
been provided in order to provide the repeater function. A point-to-point link can be
used to increase the number of effective zero-hop sites. This aids greatly in covering
haul trucks near the shovel. When a 6 dBi omni is mounted on the shovel above the
cab on the six-foot mast, a good view of other repeater site(s) should be obtained.
CRUSHERS,
OTHER
FIXED
LOCATIONS
Fixed buildings are usually good locations for repeaters since they provide AC
power so that a lower cost AC repeater may be used. Many times the top of the roof
provides a good high coverage location. If Ethernet is available at the building, then
a “wired” “zero-hop” is available.
2.2.2 Location Considerations and Antenna Selection
Section 3 in this manual provides details of the antenna patterns and gains. Each repeater location must
have an appropriate antenna selected in order to fulfill the coverage goals of that location. Typically
around the edges of the mine property, sectors are used in order to keep the RF energy on the mine
property (which also maximizes the range at that location). Sector antennas are also used against large
structures if an omni is not possible at the very top. Typically, omni antennas are used in the middle of the
mine, on rooftops, on shovels, and other high points. Dishes are only used for point-to-point links.
Always make sure that no solid reflective objects are close to an antenna and in its beam pattern. This will
result in high energy reflections which will cause null (i.e. dead areas) in you desired coverage area.