The first thing you need to consider about any scanner is what frequency ranges you're interested in monitoring.
Here are explanations for features and controls commonly found on scanners:
Attenuator. This reduces the sensitivity of a scanner in order to reduce images and other effects of strong nearby signals.
Audio squelch. This resumes scanning if a signal has no audio on a channel after pausing on the channel for a few seconds.
Autoload. This automatically stores new frequencies found during a search into the scanner's memories.
Bank. This is a way of dividing a scanner's channels into smaller, manageable blocks for specific purposes.
Delay. This determines how long a scanner pauses on a channel for another transmission before resuming scanning.
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