Radar is the use of radio waves to detect and monitor various objects. The simplest function of radar is to tell you how far away an object is. To do this, the radar device emits a concentrated radio wave and listens for any echo. If there is an object in the path of the radio wave, it will reflect some of the electromagnetic energy, and the radio wave will bounce back to the radar device. Radio waves move through the air at a constant speed, so the radar device can calculate how far away the object is based on how long it takes the radio signal to return to the unit.
Radar can also be used to measure the speed of an object, due to a phenomenon called Doppler shift. Like sound waves, radio waves have a certain frequency, the number of oscillations per unit of time. When the radar gun and the car are both standing still, the echo will have the same wave frequency as the original signal. Each part of the signal is reflected when it reaches the car, mirroring the original signal exactly.
But when the car is moving, each part of the radio signal is reflected at a different point in space, which changes the wave pattern. When the car is moving away from the radar gun, the second segment of the signal has to travel a greater distance to reach the car than the first segment of the signal. As you can see in the diagram below, this has the effect of "stretching out" the wave, or lowering its frequency. If the car is moving toward the radar gun, the second segment of the wave travels a shorter distance than the first segment before being reflected. As a result, the peaks and valleys of the wave get squeezed together: The frequency increases.
Based on how much the frequency changes, a radar gun can calculate how quickly a car is moving toward it or away from it. If the radar gun is used inside a moving police car, its own movement must also be factored in. For example, if the police car is going 50 miles per hour and the gun detects that the target is moving away at 20 miles per hour, the target must be driving at 70 miles per hour. If the radar gun determines that the target is not moving toward or away from the police car, than the target is driving at exactly 50 miles per hour.
Police officers have been catching speeders this way for more than 50 years. Recently, many police departments have added a new sort of speed detector, one that uses light instead of radio waves. Although we have speed limit signs that tell us how fast to go, and a police offocer can almost certainly observe a speeder, we have radar as another means to insure their victory in court.
A car itself could never be made to be "stealth" to radar, simply because of the way they are shaped. You could go as fas as to buy the Radar absorbing paint (at $200.00 a quart last I knew), and use it to cover your front and rear end, but who know if that would even work.
Detect the presence of an object at a distance - Usually the "something" is moving, like an airplane, but radar can also be used to detect stationary objects buried underground. In some cases, radar can identify an object as well; for example, it can identify the type of aircraft it has detected.
Detect the speed of an object - This is the reason why police use radar.
Map something - The space shuttle and orbiting satellites use
something called Synthetic Aperture Radar to create detailed
topographic
maps of the surface of planets and moons.
As of the year 2002, those frequencies mandated by the FCC have
remained
unchanged.
As of the year 2002, Pennsylvania Muncipalities are not allowed to
use Radar, or Laser, only State Troopers are permintted.
If any state or authority is found to be using radar freqiencies
other
than what is allowed by the FCC, they are in violation of FCC law, and
can be prosecuted. All speeding tickets, and penalties determined
to have been issued during that time have to be reversed.
1. Always fight the speeding ticket, you have the chance that the
officer
will not show up, meaning there is no case.
2. Ask for the Calibration records in court. If the calibration
was over a month, the ticket is invalid.
3. Plead with the officer and judge, explain how you would pay the
fine, but can't afford the points. This usually leads to
five MPH over the limit, which will not appear on
your record.
If you are a repeat offender in the SAME court, then these will not
help you past the first time around.
Instant on radar radar is almost alwaysed used with a VG-2, leaving motorists vunerable to receiving two tickets, one for the traffic violation, and one for having the radar detector. Having a radar detector cabable of detecting VG-2 may alert a driver to the presense of a speed trap.
Detector makers did two things to defeat the VG-2. First they
changed their lo frequency. Second, and most clandestine, was to detect
the VG-2's microwave leakage, shut down the detector until the threat
was passed, and then turn back on the detector. It is called VG-2 Alert
or a radar detector / detector / detector. During the period a
VG-2 signal is detected, a radar signal can't be
detected. However, because the VG-2 alert has confirmed that
radar
is present, you are already aware of the potential for speed
monitoring,
and can adjust your speed accordingly. Laser detection is not
affected
while a VG-2 signal is present.
You deserve the right to protect yourself against the mistakes, and misuse of speed enforcement technologies, and the best way to do so is with a detector.
The myth-makers want you all to believe that police radar is infallible. No speed enforcement technology is free from mistakes, especially radar in any of its forms. Even the much hyped laser can register inaccurate readings. Radar is far too easy as a means of raising revenue rather than improving safety. Photo radar in particular is not cost effective unless it can gernerate large volumes of citations.
This leads to the question: Why oppose detectors when there is no safety problem, but there are documented problems with enforcment technologies? You would not like to agree that GREED plays a great part of the issue, and there are groups and corporations that want to see you ticketed (especially insurance companies).
One group, actually called RADAR (Radio Association Defending Airwave Rights), has long argued that some insurance companies want radar detectors banned to make it easier to write tickets, and win the convictions, which allows insurance companies to add surcharges, and high risk factors to their premiums, to people who may not actually be a poor risk. In 1992 RADAR uncovered evidence of the profit motive at work: It is no secret that insurance giant Geico, generously donates $3700.00 laser speed guns to police agencies across the country, stipulating only that officers use them daily to write tickets. What wasn't well known, was that a Geico subsidary loaned $950,000.00 to struggling speed gun manufacturer Laser Technologies, Inc. In return, Geico got 10% interest on its money, over 350,000 shares of LTI stock for $1.00 each to 100 lasers a year. One estimate valued Geico's return at $2.3million - not to mention the potential ptofits from policy holders who get ticketed by Laser!
Traffic deaths have been fallng since 1988, and in 1992 dropped to the lowest level in 30 years. These improvements also come at the time where highway speed limits have been raised. There is no radar detector problem, other than the one some companies and organizations have with people avoiding tickets they don't deserve. The fact is, drunk drivers cause more highway accidents and deaths a year than speeding motorists.
Radar detector use has been studied numerous times, and no links have been found to uncover detector use and accidents. Instead, the studies have found that radar detector use as a class, do not travel faster or become involved in accidents more often that other drivers. One research group concluded that a ban covering trucks and buses would cost states more than $900million to enforce, with little or no improvement on safety. Check the federal court records, and see just how many accidents, or fatailties were associated with radar detectors (or cell phones). The simple fact is, streets and highways are becoming markedly safer.
Myth: Radar Detectors are a safety hazzard
Fact: There is no link between detectors use and speeding
accidents,
or unsafe driving. In recent years, as detectirs use has
increased,
so has highway safety.
Myth: If you get a speeding ticket, you probably deserved it.
Fact: Police radar, and all other technolgies, make mistakes,
and can be misused.
Most police monitoring a highway will not even bother with you unless you are going way over 70mph, unless it's it's quota time at the end of the month where they only allow you 5mph over the posted limit.
There is a quota police have, no matter what anyone says. The
Federal Government specifies that X number of tickets must be written
each
month. If not, they loose grants, and other monies given to them
by the Government.