User's Manual

SCAN TABLES
OVERVIEW OF SCAN TABLES
120 ENVOY™ TRANSCEIVER REFERENCE MANUAL
Overview of scan tables
A scan table is a notional grouping of channels that are stored in a transceiver. You
can add up to 20 scan tables in your transceiver, however, only 100 channels may be
scanned at any one time.
A channel can be included in more than one scan table. Each scan table has a name, a
scan on/off switch, a voice detect on/off switch, a channel dwell time, and a data detect
on/off switch.
NOTE: The default channel dwell time for a Selcall HF network is
0.25 sec/channel. The default channel dwell time for an ALE/CALM
HF network is 0.125 sec/channel.
NOTE: If the channels are scanned for voice, the channel dwell time defaults
to 0.55 sec/channel regardless of the type of HF network. If the
channels are scanned for data, the channel dwell time defaults to
0.6 sec/channel regardless of the type of HF network.
The grouping of the channels enables the transceiver to perform common operations
on the included channels.
In order that a channel or group of channels is scanned, the following must occur:
• the channel must be included in a scan table
• the scan table must be set up to be scanned
• the transceiver must have scanning switched on
When a transceiver is scanning, it is listening for a voice and/or data signal, a
preamble signal, or both. The transceiver listens for a pre-determined dwell time on
each channel. If it detects a preamble signal, it waits to hear the address of the station
to which the call is addressed. If the address sent matches the self address of the called
station, the transceiver switches off scanning and opens the mute (if it is not already
open).
It is recommended that scanning is switched on when you are not using the transceiver
to communicate. This ensures that you can receive calls from stations using the
channels that your transceiver is scanning.