Uniden LRD747, Reference Manual

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SPEED DETECTION SYSTEMS
A speed detection device (often called a radar gun) sends out
either a microwave signal or beam of light. When this signal
reaches its target, part of the signal is reflected or bounced back
toward the emitting gun. The time required for the signal to leave
the gun, bounce off an object, and return is used to determine a
vehicle’s distance and speed.
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RADAR
Radar (Radio Detection and Ranging) is a microwave system for
detecting the speed of moving objects by reflected pulses of high
frequency radio waves. There are three radar bands
(microwave frequencies): X band (10.49 to 10.56GHz), K band
(24.04 to 24.26GHz), and the “superwide” Ka band (33.4 GHz to
36 GHz).
The X band was the first used for traffic, followed by the K band
which is harder to detect (most instant-on radar is K band). The
Ka band was introduced in 1987, and widened to Ka SuperWideband
in 1990 by the FCC. The LRD 747/LRD 757 monitors all current
radar bands including the entire Ka SuperWideband.
The radar beam is cone shaped — the narrower the beam, the
greater the resolution. A moving vehicle reflects radar signals
back towards the radar gun. The LRD 747/LRD 757 can detect the
signals emitted by radar guns, and it will sound an audio alarm
and flash a warning indicator. For continuously transmitting
radar, use the LRD 747/LRD 757 to get accurate detection from a
safe distance. Weak signals cause the audio and visual alarms to
sound intermittently, but as the signal gets stronger (the closer
you get to the radar gun), both alarms increase in intensity.
Instant-on transmitters fire a short radar pulse beam at a vehicle
and instantly read its speed. When detected at a distance, you will
hear a few beeps and see the strength meter begin to light.
Instant-On radar signals are the most difficult to detect at a safe
distance because they are transmitted only when directed at you
or at a vehicle directly ahead of you.
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SPEED
DETECTI
ON
IMPORT
ANT
INFORMA
TION
ABOUT
YOUR
NEW
LASER/R
AD
AR
DETECTOR
C:\Manuals\LRD747\LRD747-757.vp
Tue Oct 05 11:28:43 1999
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