Operator`s manual

4-1
June 1997
Part No. 002-0690-201
RECOVERY (REVERTS)
SECTION 4 RECOVERY (REVERTS)
CAUTION
Reverts require extreme caution and knowledge
about the radio system. Otherwise, reverts could
cause more problems than the initial failure.
Reverts are actions that are performed if failures
occur. Automatic actions can be configured and per-
formed through OpenView. If there is a failure, the
remaining working pieces need to be reconfigured to
provide the best possible coverage for the system’s
communications needs. By setting up channel reverts
and site reverts, OpenView can provide automatic
reconfiguration.
Channel reverts will shut down all repeaters on a
channel. Site reverts will shut down individual sites or
reconfigure individual sites to stand-alone sites. If a
repeater failure can cause both reverts, both reverts
will occur.
Some situations will be beyond the scope of auto-
matic reverts. Therefore, it is possible to manually
revert channels and sites. Channels and sites are
always manually unreverted (returned to normal).
Repeaters can also be individually controlled.
Automatic actions are configured by the System
Manager.
4.1 CONSIDER INTERFERENCE PROBLEMS
In a simulcast system, the repeaters in adjacent
sites are on the same channel and purposely overlap to
fill in weak coverage areas. If one site is reverted to a
stand-alone Multi-Net site, the overlapping areas will
have interference problems. See Figure 4-1.
Interference problems could be minimized in sev-
eral ways. Reducing the output power level of the
repeaters in Site 1 (Figure 4-1) might decrease the area
affected by interference; however, it may also create a
hole in the coverage area of the system. Reduced
power level may also put more stations in fringe areas.
If only one repeater is not working at Site 1
(Figure 4-1), the channel with the non-working
repeater could be shut down. That is, the repeaters in
sites 2 and 3 for that channel could be disabled. Except
for having one less channel, the system would con-
tinue to function as a normal simulcast system.
If a system has enough channels, each site could
use different channels and be reverted to a stand-alone
Multi-Net site. The benefits of simulcast coverage
would be lost, but the holes and fringe areas would be
reduced.
There will be trade-off decisions that must be
made when equipment fails. Knowing the coverage
area of the working repeaters and considering the
effects on the whole system will lead towards a config-
uration that minimizes the loss as much as possible.
Figure 4-1 REVERTED SITES CAN CAUSE INTERFERENCE
Site 1
Site 3
Site 2
Site 1
Site 3
Site 2
In a simulcast system, all radios
receive the same signal.
If Site 1 is reverted to a stand-alone Multi-
Net site, radios in the black area will receive
a signal from Site 1 and a different signal
from Sites 2 and 3.