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LBI-39015
MONITOR (CLR) SWITCH OPERATION IN
SCAN
The CLR switch does not operate while scanning inac-
tive channels. When a channel becomes active, the CLR
switch operates only during the scan hang time after the
channel activity disappears.
CHANNEL CHANGES IN SCAN
Pushing the channel switches (UP or DOWN) while scan
is turned on will change the SELECTED channel assign-
ment. If a signal is being received and the channel switches
are pushed, the radio will revert to the new SELECTED
channel assignment. The channel indicator display will show
the new assignment. After 2 seconds, if no activity appears
on the new SELECTED channel, scanning will resume. If
the SELECTED Channel is changed to a channel not in the
scan list, the new channel will be temporarily added to the
scan list until the SELECTED channel is changed again.
Temporary Channel Deletions:
The SCAN function must be turned off to make any per-
manent changes (additions, deletions, priorities) to the scan
list. While in scan, temporary channel deletions may be
made to the scan list. The original scan list will be back in
effect by either turning scan off (by pushing the SCAN
switch) or by turning the radio power off and back on.
When the radio stops scanning on an active channel, the
channel may be temporarily deleted by pressing the pro-
grammed flex key mapped to scan add/delete. The radio will
immediately resume scanning while skipping over the tem-
porarily deleted channel.
Temporary deletions cannot be made until the radio stops
on an active channel. P1 and P2 channels cannot be tempo-
rarily deleted.
PC PROGRAMMING SCAN OPTIONS
1.
Scan Hang Time:
A scan hang time is applied after the carrier on an
active channel disappears and after releasing the
transmitter PTT. The hang time prevents momen-
tary signal fades from resuming scan (which would
cause big gaps in the receive audio ) and allows
time to respond to a received call. The hang time
also prevents the radio from immediately leaving
the channel and resuming scan when the PTT is re-
leased to allow time for a return call. The scan hang
time is normally 2 seconds in length and PC pro-
6
grammable from 0.3 to 5 seconds on 0.1 seconds
steps. If no other channel activity occurs during this
time, scanning will then resume. The priority chan-
nels are still being sampled during the hang time.
2.
Hang Time After PTT Release:
YES (default): If off-hook scan is enabled, after the
PTT is released, the radio will not stay on channel
but will immediately resume scanning. The scan
hang time will still be applied after a received car-
rier disappears.
NO: If off-hook scan is enabled, when the PTT is
released, the radio will not stay on channel but will
immediately resume scanning. The scan hang time
will still be applied after a received carrier disap-
pears.
3.
Scan For Channel Guard:
YES: The radio will stop scanning only on active
channels with the correct Channel Guard. If a scan
channel has Channel Guard programmed, the radio
will scan only on noise squelch operation for that
channel.
NO: The radio will ignore Channel Guard and scan
only on noise squelch operation.
4.
Scan Transmit Channel:
SELECTED channel (default): The radio will al-
ways revert to SELECTED channel when the mi-
crophone PTT is keyed or when the microphone is
placed off-hook (if off-hook scan is disabled). If
signals not being received, the radio will transmit
on the SELECTED channel.
5.
Off-Hook Scan Enable:
NO: (default): The radio will stop scanning and
flash the SCN indicator when the microphone is
off-hook. See the "scan transmit channel" descrip-
tion above to program where the radio will trans-
mit.
YES: The radio will continue scanning with the mi-
crophone off-hook. See the "scan transmit channel"
description above to program where the radio will
transmit.
Figure 1 - Scan Operation Flow Chart
6.
Priority 1 Channel Programming:
• Method 1 - Front programmable (default)
P1 is added to the scan list using the front control panel.
• Method 2 - Fixed P1 Option
P1 channel is PC programmed into the radio personality.
• Method 3 - SELECTED channel option:
The P1 channel follows the SELECTED channel. Each
time the scan function is turned on by pushing the
SCAN switch, the P1 channel will then follow any
changes in the SELECTED channel assignment when
the channel switches are pushed.
DETAILED SCAN OPERATION
The scan operation is controlled by the Audio /Logic Board
and provides for scanning any or all of up to 16 channels. The
scanned channels may be located anywhere within the fre-
quency band of the radio and can include two priority channels
(P1 and P2).
If desired, all 16 channels can be scanned with or without
priority level. When SCAN is enabled, scanning of the selected
channels starts immediately. Scan time is approximately 15 to
160 milliseconds per channel, depending upon whether Chan-
nel Guard has been programmed for a particular scan channel.
If a carrier is not detected, the scan time is 15 milliseconds. If a
carrier is detected and Channel Guard is programmed for the
channel, the scan time is 75-175 milliseconds, depending upon
how close the Channel Guard tone is to the desired tone. Typi-
cal value is less than 175 milliseconds.
Priority 1 (P1) and Priority 2 (P2) channels, if present, are
not part of the non-priority channel scan list (S1, S2, S3,...) and
are treated separately. If there is no activity on any of the
scanned channels, then the scan sequence is as shown in the
following example.
Example 1: (More than four Non-priority channels, i.e., six channels)
P1-P2-S6-S5-S4-S3-P1-P2-S2-S1-S6-S5-P1-P2-S4-S3-S2-S1-P1-P2-...
Example 2: (Four or less Non-Priority channels, i.e., three channels)
P1-P2-S3-S2-S1-P1-P2-S3-S2-S1-P1-P2-S3-S2-S1-P1-P2-S3-S2-S1-...
Therefore, the scan sequence is: Scan P1 and P2 pro-
grammed. Then scan up to four non-priority channels before
scanning P1 and P2 again. If more than four (4) non-priority
channels exist, then scan will wrap around, continuously scan-
ning four channels of the non-priority list between each P1, P2
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