Road Patrol XK Superheterodyne Radar Detector
(220-1621)                 Operation                  Faxback Doc. # 17809

POWER SWITCH

Press the power switch to turn the detector on or off.  When you first turn
on your detector, it performs a self-test on all its circuits.  This test
takes about 6 seconds.  During this test, alert tone sounds and/or the
warning indicator lights.  You can set the tone volume during the test.

After the test confirms that the unit is operating, the tone stops and the 
indicator turns off.  The green power indicator should remain on.  If the
green power does not stay on, or if the unit turns on and off or the alert
tone sounds often for no reason, check the connection of the power cable
at both ends to be sure it is not loose.

SENSITIVITY SWITCH

In highly populated areas, there are many devices that use X-band
frequencies for motion detection or intrusion alarms.  These devices can 
trigger an alert on the detector.  You can adjust the detector's X-band 
sensitivity to help avoid these annoying false alarms.  Set the HWY/CITY
switch to CITY to mute most of these weaker signals.  When you drive on the
open road, set the switch to HWY for full X-band sensitivity.  K-band
sensitivity is not adjustable-this assures optimum detection of "instant-
on" radar signals.

VOLUME CONTROL

Turn the volume control to adjust the alert tone's volume level as desired.

BUZZER/BOTH/LIGHT SWITCH

When the unit detects a radar signal, it alerts you visually, audibly, or 
both.  Choose the desired setting of the BUZZER/BOTH/LIGHT switch.

BUZZER = Only sound alert

LIGHT = Only visual alert

BOTH = Sound and visual alert

The rate of the beeps and/or flashes increases as the radar signal 
strength increases.

SIGNAL STRENGTH METER

The signal strength meter's five indicators provide a visual indication of
the strength of radar signals-the more indicators that light, the stronger
the radar signal.

RADAR DETECTION

Two criteria determine the performance standard of your radar detector-
selectivity and sensitivity.  Selectivity refers to the quality of the 
warning signals and the unit's ability to reject certain signals/
frequencies.  Sensitivity refers to the minimum signal strength needed to 
produce an output.

Together these two factors make up the "superheterodyne" technology used 
in radar detectors since 1976.  Originally, conventional radar detectors 
needed a direct signal to register the presence of police radar.  Super-
heterodyne technology is sensitive to both direct and indirect incoming
radio frequencies and electronically processes these signals to verify
their authenticity.

Think of it this way.  A water glass is your radar detector and the water 
is police radar.  It takes a certain amount of water (radar) in the glass 
to over-flow (activate the radar warning signal).  But the Micronta Road
Patrol XK Radar Detector has a pre-loaded signal (full glass of water), so 
it takes only one drop of water to overflow or set off the warning.

The detector is so sensitive that even a fraction of police radar scatter 
(energy) will activate it.

SCATTER

The term "effective working distance" means that a vehicle is close enough
to reflect the transmitted radar signal with enough strength to give a
reading.  But the signal itself travels far beyond that point.  This
portion of the signal is called "scatter" and can be present several miles
from the police radar unit.  Your radar detector can pick up these scatter
signals, but the signals returned to the police receiver unit are too weak
to accurately register your speed.

For example, in the drawing at right, Vehicle B (with the Micronta Road
Patrol XK Radar Detector) receives warning of police radar far in advance
of Vehicle A, which uses a conventional radar detector.

THE SCIENTIFIC PRINCIPLE

Police radar operates on a scientific principle called the Doppler Effect.
When the narrow microwave beam strikes a moving object, such as your car,
a signal is reflected off the vehicle.  The frequency of this beam
increases or decreases depending on the speed and direction of the object
it hits.

The police radar unit compares the reflected signal with the original
signal and electronically computes the difference.  Then, the speed of the
vehicle appears on a digital readout display.

RANGE 

The maximum operational range of the best police radar is about 2,500 feet
for automobiles and 3,500 feet for large trucks.

Police radar uses super-high frequencies.  As the signal travel, they widen
and become conical - like a headlight beam at night.  Even when your car
travels on a curving road, the conical transmission of the police radar
will fan out enough to encounter your car.

Three factors affect police radar efficiency:

    Microwave signals travel in straight lines and are, therefore, limited
    to line-of-sight use.  (See the drawing below.)

    The reflected signal is much weaker than the transmitted one.  The 
    transmitted signal can reach as far as five miles.  But the approaching
    vehicle must be close enough to reflect the signal with sufficient
    strength to be detected and monitored by the receiver portion of the 
    police radar unit.

    Besides checking speed with radar, a police officer must be able to
    identify the speeding vehicle in order to give a ticket.  And beyond
    1,700 feet, visual accuracy is questionable.

NOTE:  Based on the above conditions, stationary police radar is normally
       adjusted to an "effective working distance" of up to 1,500 feet.
       Moving radar is adjusted for up to 2,000 feet.

SPEED DETECTION

Police radar is extremely accurate to one-tenth of a mile per hour provided
the vehicle is within range and is moving directly toward or away from the
transmitted signal.  The following illustrations illustrate more clearly
the principles of radar detection.

    Radar does not pick up either vehicle A (outside effective working
    distance) or Vehicle B (out of line-of-sight).

    Police radar will indicate an inaccurate speed (always reduced) when
    the signal reflects from a vehicle at an angle.

    A vehicle traveling at a 90 degree angle to the radar beam will
    reflect zero speed.

NOTE:  Measurement of speed for a vehicle traveling at an angle to the 
       radar beam is reduced from the actual speed as the angle widens.
       True speed is measured only when the vehicle is moving directly 
       toward or away from the radar beam.


(WL/all-11/13/95)

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