Explanation
A patrol car is traveling in front of you with a radar
source aimed forward. Because signals are
sometimes reflected off of large objects and
sometimes not, the alerts may seem inconsistent.
A patrol car is approaching from the other
direction, “sampling” traffic with instant-on radar.
Such alerts should be taken seriously.
You are driving through an area populated with
radar motion sensors (door openers, burglar alarms,
etc.). Since these transmitters are usually contained
inside buildings or aimed toward OR away from
you, they are typically not as strong or lasting as a
real radar encounter.
CAUTION: Since the characteristics of these
alerts may be similar to some of the preceding
examples, over confidence in an unfamiliar area
can be dangerous. Likewise, if an alert in a
commonly traveled area is suddenly stronger or
on a different band than usual, speed radar may
be set up nearby.
Alert
PASSPORT alerts intermittently. Rate and strength of
alerts may be consistent or vary wildly.
PASSPORT alerts intermittently. Rate and strength of
signal increases with each alert.
PASSPORT gives an X-band alert intermittently.
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Interpreting Alerts
How Radar Works
Traffic radar, which consists of microwaves,
travels in straight lines and is easily
reflected by objects such as cars, trucks,
even guardrails and overpasses. Radar
works by directing its microwave beam
down the road. As your vehicle travels into
range, the microwave beam bounces off
your car, and the radar antenna looks for
the reflections. Using the Doppler
Principle, the radar equipment then
calculates your speed by comparing the
frequency of the reflection of your car to
the original frequency of the beam sent out.
Traffic radar has limitations, the most
significant of these being that it typically
can monitor only one target at a time. If
there is more than one vehicle within
range, it is up to the radar operator to
decide which target is producing the
strongest reflection. Since the strength of
the reflection is affected by both the size of
the vehicle and its proximity to the
antenna, it is difficult for the radar operator
to determine if the signal is from a sports
car nearby or a semi-truck several hundred
feet away.
Radar range also depends on the
power of the radar equipment itself. The
strength of the radar unit's beam
diminishes with distance. The farther the
radar has to travel, the less energy it has for
speed detection.
Because intrusion alarms and motion
sensors often operate on the same
frequency as X-Band radar, your PASSPORT
will occasionally receive non-police radar
signals. Since these X-Band transmitters are
usually contained inside of a building, or
aimed toward the ground, they will
generally produce much weaker readings
than will a true radar encounter. As you
become familiar with the sources of these
pseudo alarms in your daily driving, they
will serve as confirmation that your
PASSPORT’s radar detection abilities are
fully operational.
How “POP” Works
“POP” mode is a relatively new feature for
radar gun manufacturers. It works by
transmitting an extremely short burst,
within the allocated band, to identify
speeding vehicles in traffic. Once the target
is identified, or “POPPED,” the gun is then
turned to its normal operating mode to
provide a vehicle tracking history, (required
by law).
NOTE: According to the operator’s
manual from the radar gun
manufacturer, tickets should not be
issued in this mode.
How Radar Works
How POP Works
