User's Manual

Operation DMH Series VHF Radio
BK RADIO Page 3-13
3.11 PRIORITY SCAN
Priority Scan enables the radio to receive on any channel while monitoring for a
message on the designated priority channel(s). The radio samples each priority
channel at a preset rate (.25-2.0 seconds) regardless of activity on any other
channel. Priority Scan operates only while the radio is not transmitting and can be
used in combination with scan operation.
When Priority Scan is on, the PR annunciator illuminates, and the display flashes
SCN (alphanumeric mode) or two flashing bars (numeric mode). If a message is
received on a priority channel, the Priority indicator illuminates, and the radio receiver
locks onto that channel for the duration of the transmission, unless a higher priority
channel interrupts.
Priority Scan can be used in combination with Channel Guard with:
• Priority Scan on (arrow appears above PRI button)
• The Squelch knob in the Channel Guard position (fully counterclockwise detent
position) and
• Channel Guard Disable off (no arrow above CG button)
• The Priority Channel(s) programmed with Channel Guard
If a message is received on a priority channel, the radio receiver locks on to the
priority channel and checks to see if the proper Channel Guard value is present. If
the signal contains the proper Channel Guard value, the radio receives the message.
Otherwise, the radio will re-check the channel every 4 seconds, until the activity on
the channel ceases.
3.11.1 DUAL PRIORITY SCAN
In each group, up to two of the 16 channels can be designated as priority channels.
These two, PR1 and PR2, are periodically tested for activity, even if a different
transmission is being listened to. Activity on PR2 preempts activity on any of the
non-priority channels. Receptions on PR1 have priority over any other channel in the
group, including PR2.
Either priority channel can be programmed as a fixed channel, tied to the Channel
Selector knob, or programmed OFF. If the radio is programmed to transmit on the
first priority channel, transmissions will occur on PR1 if PR1 isn’t programmed OFF,
when operating in Dual Priority Scan Mode.
If PR1 is a fixed channel, and changes to the 1
st
priority channel are allowed, and the
[PRI] key is not locked out, the user can move the channel selector to a new channel
and press and hold the [PRI] button for more than 1 second to choose a new PR1
channel.
Dual Priority Scan is automatically disabled when Group Scan is on.
3.11.2 OLD-STYLE BK PRIORITY SCAN
The radio can be programmed with one of three Priority Modes: A, B, or C. The table