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- [ -------------------------------------------------------------------------- ]
- [ - The Modern Speeders Guide to Radar and State Troopers - ]
- [ - By : Exilic Xyth - ]
- [ - January 11, 1988 - ]
- [ -------------------------------------------------------------------------- ]
-
-
-
- Introduction:
-
- Touched off by the discussion on Ripco <312>-528-5020, I
- found many users asking questions about police radar, radar detectors, and
- speeding. With Ron Majors talking about the oil spill that will appear in
- detail on the news at ten I thought a informative file on the subject might
- be beneficial. I myself had my first experience with police radar in my
- fathers car, then following in baseball and my own driving, much more on the
- subject. What a fascinating device, that it will return your speed instantly,
- what fun one would be to have! After a quick talk with a police friend of
- mine, I soon took possession of a used police radar gun.
-
- Part one: Operation.
-
- Police Radar works via the doppler effect, best
- demonstrated by sound rather than microwaves. The doppler effect is the
- relation of speed to the pitch of 'sound'. Sometime, all of you must have
- had the distinct pleasure of being honked at by a motorist on the go,
- you might have noticed that the horn <an F flat on most american cars>
- begins with a higher pitch and as the car passes, drowns off to a lower
- tone. The sound waves at the front of the car are pressed together by the
- forward motion of the car, creating a higher pitch. As the car passes,
- the tone dies off to a lower pitch because the waves are spread out.
- Police radar works in much the same way. The major differences are the
- frequency and the concentration of the carrier.
- As of 1988, the F.C.C. is rumored to have lifted restrictions
- on police radar frequencies. Before, only two frequencies were approved for
- police radar use. X-band <10.525 GHz> which is most commonly used, and
- K-band <24.15 Ghz>. I will assume for now, due to lack of any SOLID evidence
- supporting the restriction lift, that those are the only two in operation.
- Police radar 'beams' are similar in shape to a flashlight beam. They begin
- with a thin width and cone outwards with distance. Most guns operating at
- the X-band level have a range of about 2000 ft., although high power units
- can exceed 2500 and 3000ft., and K-band guns fall shorter at about 1200 ft..
- At 1500ft., the radar beam becomes about the width of four highway lanes, so
- for practical purposes radars range is around 1700 ft.. A radar signal
- transmitted from the 'Radar Gun's' transmitter, (called the oscillator) will
- bounce off a object and return to the radar receiver (or antenna). If the
- object is moving, the frequency of the beam will be altered as it bounces.
- This is most easily visualized watching water ripples. Assume now that I
- have just dropped a pebble in a pond, and the ripples are moving outward,
- assume also for purposes of simplicity that the ripples are moving at
- 1 foot per second, and that they are one foot apart. The ripples are
- therefore also one second apart. Upon bouncing off a stationary object
- the ripples will return weakened, but at the same interval and speed
- <Not really the same speed, but let's not complicate things>. Now let
- us assume that a toy boat is traveling in the water at .5 ft. per second,
- 1/2 the speed of the ripples, away from the point which I dropped the
- pebble. Assume the first ripple has hit the boat and is traveling back.
- The second ripple now traveling at 1 foot per second is only gaining on the
- boat by .5 feet per second <1 ft. per second - .5 ft. per second>. This means
- that the ripple is one foot away from the boat, as the ripples are one foot
- apart. The ripple will take 2 second to reach the boat, as the closure speed
- is .5 ft. per second and the distance is 1 foot. The ripple strikes the boat
- and bounces back two seconds after the first ripple. The process works
- inversely for an object moving towards the pebbles point of impact.
- As the distance between the ripples can be determined by the speed, on the
- other side, the speed can be determined by the distance between the ripples.
- Police radar works in the same way with microwaves. The microwave signal
- bounces off a moving vehicle and returns altered in frequency. In this way
- the radar unit determines the speed of the object. Radar is only accurate
- when the object is moving directly at, or directly away from the gun,
- although some modern guns will account for this 'COSINE error', most won't.
- Cosine error can be defined as this: When a radar signal bounces off an
- object at an angle from the objects direction of travel it will return a
- portion of the objects speed computed by the cosine of the infraction
- angle. If the angle of the objects direction and the radars direction is
- 20 degrees the speed returned by the radar is 93.97% of the objects
- actual speed. cos (20) = .93969262 * objects speed = returned speed.
- For example: A car is traveling at 75 m.p.h.. The state trooper, in his
- infinite wisdom, decides to "Clock" the automobile in hopes of meeting his
- quota for the month. Picking up his handy radar gun, he aims, and fires
- an invisible beam of microwave energy. The officer however, being the rookie
- he is, leaves a high angle between the cars direction and his beam of 45
- degrees. Cos (45) = .707106781 .707106781 * 75m.p.h. = 53.03300859
- 53 m.p.h. is displayed on the officers screen. Lucky motorist.
- Sorry 40 column users.
-
- |
- |\
- | \
- | \ - Cosine Error -
- | \
- | 45 \
- | deg.\ - radar beam
- | \
- | \
- v \
- Direction of \
- cars travel \
- \
- X - state trooper.
-
- Part 2: Application
-
- In 1986, over 15 million speeding tickets were issued,
- and experts estimate that over 25% of them were in error. Police have
- been using radar for speed control for many years, and as the technology
- has become more complex and accurate, so has the ability to get away with
- the slight infractions of the speed limits set by the government become more
- difficult. In recent years, the three most damaging advances to motorists
- in radar technology include: A> Instant on radar. B> K-band radar. and
- C> Cosine error correcting radar units.
-
-
- Instant on radar.
- With the increase of radar receivers, or
- "Detectors" on the roads, police have attempted to bypass the motorists
- first line of defense. The most damaging advance in the war against speeding
- motorists is instant on radar. The idea behind instant on radar is to make
- the radar detector useless to the motorist by making his warning too late to
- react to. Instant on radar was developed in early 1983, but never marketed
- until late 1984 when the michigan state troopers were equipped with the first
- instant on radar guns. It operates by deactivating the oscillator until
- triggered by the officer. When used properly and under the right traffic
- conditions, it is indefensible. It works like a camera, the officer
- operating the radar will position himself behind a blind corner or over a
- hill. When the approaching car crests the hill or rounds the corner, the
- officer will activate the oscillator, taking a "snapshot" of your car.
- As microwaves travel at the speed of light, any attempt at slowing down
- is futile, the officer behind the gun has your speed in less than a tenth
- of a second.
-
- K-band Radar.
- When radar detectors were first marketed by
- the markers of ESCORT, there was only one type of radar. X-band.
- In an attempt to increase the dwindling speeding ticket revenue, K-band
- was brought to life. K-band is a different frequency that could not be
- picked up by the primitive detectors of the age. However, as the
- frequency got out, the detectors adapted, and now any detector worth a dollar
- will detect both X and K bands. K band is more dangerous as most K-band
- guns are instant on and they have less 'Splash' and range than X-band guns.
- This means that a K-band signal is probably closer to you.
-
- Cosine error correcting guns.
-
- Cosine error was a major falling of radar
- in the judicial system, all readings were under question in court, the
- result was a gun which will correct for cosine error by determining the
- angle which the radar beam "impacts" with the car. Also new in correcting cosin
- e error were guns with 'Speed lock on' in which the highest speed reading
- received by the gun is locked in and displayed.
-
-
- Moving radar guns.
-
- Until new developments, all radar units
- had to remain stationary as radar measures only closure speed, and not actual
- speed. Moving radar ended this trend. Moving radar works like this. First the
- radar gun determines the patrol cars speed by clocking a sign or fixed
- object. The closing speed of the patrol car to the sign is subtracted from
- the now taken closing speed to the target car.
- Patrols speed - 60 m.p.h.
- Closing speed to car - 120 m.p.h.
- 120 m.p.h. - 60 m.p.h. = 60 m.p.h..
-
-
- Part 3: Defense
- From the dawn of speed enforcement, motorists have sought
- to defeat the laws, starting with detectors, continuing to jammers and
- topping out with the new 'CHiPs detectors' The unfortunate conditions
- now favor the police and law enforcement officials with the introduction
- of new radar technologies such as instant on radar.
-
- Detectors:
-
- The simple radar receiver is the first line of
- defense from radar. Varied in operation and features, the radar detectors
- of today are designed to provide high sensitivity and low rates of false
- alarms. Good detectors will measure signal strength and type <K or X>
- and have an effective range of about 3000 ft. and a probable range of well
- over a mile. Sensitivity tops out around 110.5 dBm/cm^2 for X band and
- 108 dBm/cm^2 for K band <Both set by the passport>. A detector can give
- you an excellent advantage over radar by alerting you it's there. Detectors
- become especially useful in chicago where instant on radar is not typically
- used.
- Jammers:
- Radar jammers are essentially units that
- transmit microwaves at a frequency dictating a certain speed. The result is
- regardless of your speed, the police radar unit will display the speed you
- set the jammer to transmit. Jammers are highly illegal and will be
- confiscated if discovered, expect a stiff fine.
-
- Chip's detector.
-
- This is a new device, which is really a scanner
- on the police radio band. It takes advantage of a signal transmitted by the
- patrol cars in some states as part of their dispatch system. The signal
- carries for about three miles, and the Chip's Detector will alert you if you
- are within that range of a highway patrol unit. It also allows scanning
- of police radio channels.
-
- Last words.
-
- Radar is a basically accurate instrument, when used
- properly, it can be deadly. As I have said before instant on radar is
- impossible to avoid when there is no other traffic around, regardless of
- a detector. The only thing that comes close is a Radar Jammer, which
- will most likely not serve you well unless it is WELL hidden. Radar
- jammers are dangerous with the introduction of the HAWK, a radar unit by
- Kustom Signals, which DETECTS radar jammers in the hold mode.
- Aside from radar, VASCAR
- <Visual average speed computer and recorder>
- is a new danger to motorists. It is basically a stopwatch
- used to time your movement between two point of which the interval distance
- is known. Using the formula Average velocity = distance / time, the state
- trooper can determine your speed without setting off your detector.
- Instant on radar defense.
-
- The only real defense for instant on radar
- is traffic. Traffic will cause the trooper to activate his radar gun more
- often, cluing you into his presence. A jammer well hidden will help,
- but the best technique is to follow a car making good time. Any police
- units in the area will clock him first, and legally they have to ticket him,
- unless you're too close.
-
-
- Remember:
- Do not speed, it is a dangerous practice, and I can not be responsible
- for any injury, or action due to this file, it is for informational
- purposes only. The state troopers enforce speed limits for your
- safety.
-
- Radar guns: Models.
-
- Radar guns are manufactured by many different
- companies, but the primary ones are Kustom Signals, M.p.h. Industries, and Decat
- ur.
- The deadliest gun now available is the HAWK
- manufactured by Kustom Signals. It is the first gun capable of clocking
- cars moving the SAME direction as the patrol car. It has two antennas, one
- forward, and one back. Like I stated before, it is also the first gun capable
- of detecting radar jammers. These run about 2000$
-
- Kr-11
- This gun is a two piece model which uses
- a weak pulse signal in the moving mode to determine the patrol car's speed
- while not triggering detectors. This gun permits a faster clocking time for
- instant on moving radar, it runs about $1200
-
- Falcon
- This is a hand held gun operating on K band
- Small and compact it is preferred among law enforcement radars. It runs about
- 600$
-
- Hr-4 Hr-8 Hr-12
- 400,500,750$ respectively, these are hand
- held radar guns made by Kustom Signals
-
- All these units are available to you via me
- for less than the troopers pay for them. For prices, and statistics,
- call my board at (312) - 787 - 2174 or send me mail at Ripco (312) 528-5020
-
- Prices for radar units range from 250-2000$
- I personally enjoy harassing that 911
- who barrels by at 95 with a detector.
-
-
- Downloaded From P-80 Systems 304-744-2253
-
-