E.F. Johnson LTR-NET 8170, Дополнение к руководству по обслуживанию

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OPERATION
2-22
April 1999
Part No. 001-9800-600
set during alignment as described in the service manual
(see Section 1.5.4). In addition, three squelch levels
called Dropout, Capture, and Tight Capture Percentage
are programmed for each locality (see Table 3-3).
These levels automatically tighten the squelch setting
in certain operating modes. The tightened amount is
the programmed percentage of the difference between
the reference level and the maximum tight setting
(equivalent to rotating a squelch knob fully clockwise).
These squelch levels function as follows:
Dropout Percentage - This is the percentage that
squelch is tightened when not in a call. This prevents
the transceiver from staying on a weak locality when
another stronger locality may be nearby. The default
level is 33%, and setting higher levels may cause more
missed calls during weak signal periods. If there is no
other site nearby, this parameter should be 0%.
Tight Capture Percentage - This is the percentage
the squelch is tightened during the first pass when
searching for a new site (HSQ SRCH displayed). This
parameter should always be greater than or equal to
the Capture Percentage which follows, and it ensures
that registration occurs on a strong locality if there is
one. The default level is 80%.
Capture Percentage - This is the percentage that
squelch is tightened on the second and later passes
when searching for a new site (LCL SRCH displayed).
This parameter should always be greater than or equal
to the Dropout Percentage, and it ensures that registra-
tion occurs on a stronger site. The default level is 46%.
NOTE: The transceiver uses the value programmed
for the locality being sampled, not the value
programmed for the locality which was just dropped.
2.9.4 OVER-THE-AIR LOCALITY CHANNEL
UPDATES
Localities are initially programmed with the
channel numbers of all repeaters currently in use.
These are then the channels that the transceiver can
access when placing and receiving calls. If new chan-
nels are later added to a locality, over-the-air program-
ming is used to update the transceivers with the new
channels. This eliminates the need to bring them in for
reprogramming. Channel updates occur on only
selected repeaters, and they are initiated automatically
by the radio system.
2.9.5 TRANSCEIVER DISABLE
If a mobile is lost or stolen or is being used to
interfere with communication, it can be temporarily or
permanently disabled by the system operator.
A mobile can be temporarily disabled by trans-
mitting the Sleep command to the unique ID of the
affected mobile. When a transceiver receives this
command, SLEEPING is displayed continuously on
the lower line and no calls can be received or transmit-
ted. However, registration on new localities continues
normally.The transceiver can be re-enabled again by
the system operator by sending an Interrogate
message. This is indicated when the display returns to
its normal mode.
A mobile can be permanently disabled by sending
the Kill command to the unique ID of the affected
mobile. The transceiver then responds that it has
received this message and then permanently disables
itself. It is then totally inoperative and CALL SVC is
displayed continuously. It must then be brought back
in for reprogramming to make it operational again.
2.9.6 HOME CHANNEL ALIASING
Introduction
The home channel aliasing feature increases the
number of standard group calls programmable on a
locality. It does this by allowing calls to be
programmed on non-existent home repeaters. There-
fore, instead of being limited to just the 239 ID codes
on each active home repeater, group calls can be
programmed on each of the 20 home repeaters allowed
per locality (the twentieth repeater is usually the status
repeater which is typically not assigned as a home
repeater). This permits up to 20 x 239 or 4780 group
calls on each locality.
The active repeaters on each locality are desig-
nated by locality programming (see Section 3.6.8).
Active repeaters are programmed with a frequency and
have the Active box checked. Inactive repeaters have
the Active box unchecked. If repeaters are later added,
they can be added to the locality by over-the-air
programming (see Section 2.9.4).