How Radar Detectors Work

The How-To Behind A Radar Detector

Speeding, even just a little bit, is technically against the law. Those who do so on a regular basis are flirting with costly tickets and other hidden expenses.

For some the penalties might not seem like much, but for others, a single ticket and the subsequent increases in insurance policy premiums can break a budget.

The best way, of course, to avoid a ticket is to not speed in the first place. But, since life is never that simple, it pays for drivers to protect themselves. Whether a person is the kind of driver that just slips up once in a while or one that has a general “lead foot” issue, some advanced warning about upcoming police activity can go a long way toward helping avoid a ticket.

Knowing this, many drivers use radar detectors to help give them the edge in avoiding the ever-so-costly speeding ticket. But how do these devices work? And, are they really effective?

Here we’ll look at the basic radio wave detection devices. First, however, it’s important to understand what a detector is looking for.

Most law enforcement agencies use some type of radio transmitter to track speeds. A basic “radar gun” is simply a radio transmitter and receiver folded into a single unit. A transmitter is a machine that oscillates a current so the voltage goes up and down at a set frequency. This electricity makes electromagnetic energy, which when the current is oscillated, travels as a wave. An amplifier is included in a transmitter to increase the intensity of the electromagnetic energy and an antenna to broadcast it into the air.
The receiver does just the reverse. This device picks up the waves and turns them back into a current. The radar uses radio waves to clock objects and tell how far away they are. They can track speeds using a set formula based on the wave patterns and Doppler shift.
In their basic form, radar detectors simply alert drivers to the use of a specific radio frequency in the general area. Unlike the guns, which operate in a certain cone to “clock” a specific target, detectors read the signals within an area, which means drivers are given a warning to slow down before they’re clocked – in some cases
The reliability of detectors will vary from brand to brand and they’ll also differ depending on what type of tracking system law enforcement is using and the techniques they employ.
In the most simple form, what the police use sends out a cone of radio waves that are measured when the beam is bounced off a car or other moving object. The speed is attained using a set formula the gun can calculate. The detectors themselves scan for waves of the frequency law enforcement is known to use. They scan a general area for those waves and report back to drivers when trouble may be ahead, or in some cases behind a driver.