270 lines
15 KiB
Plaintext
270 lines
15 KiB
Plaintext
[ -------------------------------------------------------------------------- ]
|
||
[ - The Modern Speeders Guide to Radar and State Troopers - ]
|
||
[ - By : Exilic Xyth - ]
|
||
[ -------------------------------------------------------------------------- ]
|
||
|
||
|
||
|
||
Introduction:
|
||
|
||
Touched off by the discussion on Ripco <xxx>-xxx-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 cosine 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 Decatur.
|
||
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 (xxx) - xxx - 2174 or send me mail at Ripco (xxx) xxx-5020
|
||
|
||
Prices for radar units range from 250-2000$
|
||
I personally enjoy harassing that 911
|
||
who barrels by at 95 with a detector.
|
||
|
||
|
||
Questions?
|
||
The Dark Side:
|
||
(xxx) - xxx - 2174
|
||
Ripco
|
||
(xxx) - xxx - 5020
|
||
|