Beltronics Vector 970 Operating Instructions Manual page 16

Since Radar signals travel in a straight line, this Radar
encounter potentially offers maximum warning range. Once
the signal is received, the initial warning consists of an X, K or
Super Wideband Ka audio alert coupled with simultaneous
identification of the Radar band (X, K or Ka) and signal
strength in the Text Display. The number of bar graph segments
displayed depends upon the strength of the signal received. As
the strength of the Radar signal increases, the audio alert
becomes more rapid and the bar graph will display the
maximum number of five segments and the digit " " will also
appear indicating maximum signal strength. Assuming the
Radar signal remains uninterrupted, the audible and visual
alerts will clearly indicate a "weak" signal becoming stronger
as you drive closer to the Radar source. Remember, when the
police Radar source is moving toward you, the Radar signal
strength will increase much more rapidly than if you are
approaching a stationary source.
Stationary Radar aimed around a corner
2.
Under this circumstance, reaction time is considerably
reduced. Since the Radar signals are transmitted across your
line of travel, there is generally no signal available to receive
until you are relatively close to the source. Once an alert is
received, expect the strength of the signal to increase very
quickly. Advanced warning in this situation may be reduced.