Uniden BCT-12 Operating Manual page 17

4. Sometimes when you open the Squelch, you may trigger the
Alert feature even though no highway patrol cars are in the
area. If this happens, turn the SQUELCH control
counterclockwise until the "rushing" noise stops. Then turn the
BCT-12 off, and back on, to reset the Alert feature.
Note: In metropolitan areas, you may want to adjust the
Squelch control more counterclockwise to reduce the
range of the Alert feature. When set fully
counterclockwise, Squelch limits the Alert range to a
short distance.
Operating Instructions
17