Scan
Conventional Mode Scan
Scan is a feature that allows a two-way radio to automatically search through a number of channels for activity. Scan is only used on conventional channels - trunked systems have a feature called Talkgroup Scan but this uses a different mechanism. All MOTOTRBO radios support scan.
When a MOTOTRBO radio is scanning, the LED will blink amber.
Operation
By default, when the radio is scanning, it will look for activity on the channel that meets the parameters set in that channel. For example, if the Channel is digital and the RX Group List contains One Talkgroup with an ID of 1, then the radio will only regard the channel as active if all of these conditions are met. If this activity is found, the radio will stop scanning and present the received audio on the radios loudspeaker. As soon as the activity dissapears, the radio will continue scanning after the hang timer has timed out.
The Scan Sweep Timer defines how long the radio should take to pass through the channels in the Scan List. If set to zero (default) the scan time will not be zero but is dependant on the number of channels and the settings in each (e.g. the radio will need at least 30ms per channel to sample things like PL if a carrier is present).
Talkback (sometimes called Designated Talkback Channel or DTC) determines what should happen if the radio is landed on a channel and the user presses PTT. If disabled, the radio will transmit on the channel determined by the TX Designated Channel setting.
Vote Scan
Vote Scan extends the functionality of scan beyond just channel activity. With vote scan, the radio will search through the list of channels based on activity and signal strength. The decision on whether to stop on a channel, or resume scanning, is based on the Fast Vote and Start Vote parameters.
If a channel has a signal strength higher than Fast Vote, then the radio will follow what is defined by scan hang time and signaling hang time. If at any time the received signal drops below the level defined by Start Vote then the radio will continue scanning and may disregard the channel unless it's signal strength exceeds the Fast Vote RSSI again or if no other channel is found that exceeds both.
In order to use Vote Scan, a Vote Scan List needs to be added. To do this, right-button click on Scan and select Add Vote Scan List.
Vote scan is useful on analogue systems that use linked channels and the user experience is somewhat similar to that of IPSC roaming (albeit in analogue).
Scan Lists
Display model radios support up to 250 scan lists. Each scan list can contain up to 16 channels - of which one has to be the currently selected channel. Non-display models support up to 64 scan lists. Each scan list would be tied (assigned) to a channel, meaning that a user would select a channel to scan specific channels of interest.
A Scan List can contain up to two Priority Channels. These are channels that the radio will look at more often. If activity is seen on a priority channel, the radio can sound an alert and present received audio.
Roam and Scan
A radio cannot Roam and Scan at the same time. A roam list is used when the radio is on an IP Site Connect and allows the radio to automatically select a new wide area channel based on the signal strength of the repeater beacon. It is however possible for the radio to scan a channel that is part of a IP Site Connect system.
Scan in Capacity Plus
A radio will monitor the Rest Channel for calls of interest. There is no scan list as such and the user simply adds multiple talkgroups to the RX Group List.
Scan in Capacity Max
A radio will monitor the Control Channel for calls of interest. There is no scan list as such and the user simply adds multiple talkgroups to the RX Group List. When a MOTOTRBO radio is scanning, the LED will blink amber.
Effect on Battery Discharge Time
On portable radios, the downside to scan is that the radio has no chance to enter battery saver mode. So if scan i used, there will be a decrease in battery discharge time. If this is an important feature, it may be important to consider using a higher capacity battery.