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SECTION 3: UNDERSTANDING PASSPORT iQ
Understanding Your Detector
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‐ and K‐band
radar, your detector 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 PASSPORT iQ's radar detection
abilities are fully operational.
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