Whistler GT-138Xi, User Manual

Page: 21 / 32

21
SPEED MONITORING TECHNOLOGIES
Radar Facts
A radar gun operates by transmitting radio waves at certain
frequencies which reflect off objects and are then picked up by
the radar gun’s receiving section. When a radar beam reflects off
a moving target, a measurable frequency shift occurs. The radar
unit converts this shift into miles per hour to determine your
vehicle’s speed. Currently traffic radar guns operate at X Band
(10.500 - 10.550 GHz), K Band (24.050 - 24.250 GHz), and Ka Band
(33.400 - 36.000 GHz).
NOTE: A radar detector will not alarm if an officer is not
transmitting on any one of the above radar bands.
Laser Facts
It’s well documented that many radar guns cannot reliably
provide the speed of a targeted vehicle that is traveling in a
group of vehicles. In contrast, a laser gun can target a specific
vehicle out of a line of traffic and determine its speed. The
advantage of laser over radar in terms of target identification is
the result of the laser gun’s narrow beam. A radar transmission
can cover more than a four-lane highway at a distance of 1,000
feet, compared with a laser transmission which covers about 3
feet at the same distance. For best protection, keep these points,
listed on the following section, in mind:
• Because your vehicle’s license plate or headlights are the laser
gun’s primary targets, mounting your Whistler detector on the
dashboard can improve laser detection at short range.
• Do not follow closely behind any vehicle you cannot see
through. If you can’t see past a vehicle ahead of you, chances
are your detector won’t either.