The Hacker's Encyclopedia 1998/hackers_encyclopedia.iso/zines/a_m/lodhtj04.003

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The LOD/H Technical Journal, Issue #4: File 03 of 10


                             The Radar Guidebook
                                      by
                               Professor Falken


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   Anyone who has driven a car without a radar detector before, has gotten
that paranoid feeling that the cops are around radaring.  This feeling is not
a nice one; it is the feeling that somewhere somehow someone is watching you.
In this article I will attempt to explain how radar guns work, what bands
the guns work on, why they are wrong 70% of the time, how to employ stealth
technology in defeating the radar, and last but not least jamming the radar.

   RADAR stands for RAdio Detecting And Ranging.  A speed-radar gun works
under the Doppler theory.  This theory is that when a signal is reflected off
an object moving toward you, the signal will be at a higher frequency than the
initial frequency, this increase in frequency is used to calculate speed.
Many of you have experienced the Doppler effect, which occurs when a noise
from a siren increases in strength (gets louder) as it approaches and
decreases in strength (gets softer) as it moves away from you.

   Right now in the United States, there are three bands that are Federal
Communication Commission (FCC) certified for "field disturbance sensors",
known to you and me as radar guns.  These bands have proper non-technical
names, and all operate in the GigaHertz range.  GigaHertz is a measure of
frequency; one GHz equals one billion cycles per second.  Most frequency
modulation (FM) radio broadcasts are made in the 0.088 GHz to 0.108 GHz band,
in MegaHertz that is 88 MHz to 108 MHz.  The three proper names for these
radar bands are: X, K, and Ka.

   One of the older radar bands is the X band.  X band radar is the most
commonly used radar band in the United States.  X band radar transmits its
signal at 10.5250 GHz.  The wattage of the radar's signal really depends upon
the gun manufacturer.  However, most manufacturers agree that a 100 milliwatt
signal is "High-Power" and the 40 milliwatt range is "Low Power".  The gun's
range also depends upon the manufacturer.  The average maximum range of a X
band gun is 2500 feet.  That estimate is based on the assumption that the gun
is operating at full-strength (100mw).  Most radar detectors give off a
false signals on this band due to ultrasonic motion detectors employed
by various burglar alarm systems.  Large grocery stores also use these to
open the doors magically as you walk in or out.

   Another older band is K band.  K band operates on 24.150 GHz and is not as
popular as X band, but it is gaining in usage throughout the country.  The
normal signal strength of K band guns again depends upon the manufacturer,
but the ones I've seen all operate at 100 milliwatts at high-power.  These
guns have a maximum range of 3000 feet, assuming they are at 100mw signal
strength.

   A new type of radar has been introduced and assigned a frequency by the
Federal Communications Commission.  This new band has been assigned the name
Ka and has been designated a frequency of 34.360 GHz.  Current Ka technology
gives the gun a maximum effective range of 40 to 200 feet.  This band
was originally made for use with photo-radar.  The photo-radar can be set up
on a tripod on the side of the road or in the back of a police car.  The
user then triggers a button when he wants a car in the guns range
clocked, automatically taking a picture of the car & license plate.
At the time the photograph is taken a date and time is imprinted on the
picture.  The police keep one duplicate for archival purposes and sends the
other to the registered owner of the car along with ticket information and the
amount due.   This type of system can only work in places that hold the owner
of a vehicle responsible for any violations that occur with the car.  The
legal barriers for photo radar to overcome are extensive, most notably, not
giving the vehicle owner due process and the presumption of guilt.  There is
a system out now for $19.95 that defeats Ka band photo radar.  I expect it to
be illegal VERY QUICKLY once Ka is more widely used.  This little baby slips
over your license plate and acts as venetian blinds.  When looking straight at
the plate it looks like a normal plate with a black frame.  However when
looking at it from a Ka band Photo Radar's angle it looks like a license plate
with a silver streak covering the whole plate, making it impossible to
identify.  This device is called the Photobuster and is available from
most radar detector specialty stores.

   There are two different types of radar guns.  They are Instant-On/Pulse and
Constant Broadcasting Radar.  The names are self-explanatory, but I will
explain them anyway.  The constant broadcast radar continually transmits
its radar signal, and anything in its path will be clocked.  Instant-On &
Pulse radars are basically identical, and are both very deadly since they are
harder to detect as a threat.  The Instant-On gun is really nothing more than
an ON/OFF switch for signal transmission.  In order to have a pulse gun, all
a cop has to do is purchase one with a "HOLD" feature or just turn the gun
on when he/she wishes to use it.  The "HOLD" feature is simply a button that
keeps the gun on but makes sure no signal is being transmitted.  No one can
detect a gun that is off or in "HOLD" mode.  An officer using an Instant-On
radar gun will periodically check the speed of the traffic.  These samplings
can easily be detected and will give the user of a detector prior warning to
a Instant On/Pulse activated radar gun.

   Many detectors on the market today provide anti-falsing circuitry.  Falsing
is the triggering of the radar detector from something other than a radar gun.

   One or two detector manufactures make their detectors with GaAs diodes.
GaAs diodes are Gallium Arsenide diodes which are a military grade electrical
component that helps produce a good signal-to-noise ratio.

   All new model radar detectors use Superheterodyne technology.
Superheterodyne, also known as active technology, amplifies all incoming
signals hundreds of times, which makes it more sensitive and selective as to
which signals will trigger an alert.  Superheterodyne technology also gives
out a minute internal radar signal of its own, which can be picked up by older
(Pre/Early 1980's) non-anti-falsing radar detectors.  If you have a newer
model radar detector, this small internally generated signal is no problem to
your's or anyone's anti-falsing radar detecting unit.  NOTE: In states
where radar detectors are illegal (Ex. Virginia, Canada) the police have
devices which detect this Superheterodyne signal.  Police can then stop
you and confiscate your detector.  Getting around this police tactic
would be to use an early radar detector without Heterodyne/Superheterodyne
detection technology.

   Many compact/shirt pocket radar units are "exclusively made with SMD's".
These SMD's are Surface Mounted Devices and contain extremely small resistors,
transistors, diodes, and capacitors.  Just because a manufacturer uses SMD's,
that does NOT make the unit any better than a larger detector of the same age.

   Cincinnati Microwave Inc., the makers of Escort and Passport say they have
the exclusive technology for the detection and anti-falsing of RASHID VRSS
technology.  RASHID VRSS is actually the Rashid Radar Safety Brake Collision
Warning System.  It is an electronic device that operates on K band
frequencies and warns heavy trucks and ambulances of hazards in their path.
About 900 RASHID VRSS units have been prototyped in three states.  Since the
number of actual operating RASHID units is so minute, I really doubt you will
run into one.

   There are two ways a radar gun can produce an incorrect speed reading.
These are known as the Cosine Error and Moving Radar Error.  The Cosine Error
occurs when a radar gun gives a lower reading than the actual speed of the
target.  This occurs because the gun can only measure the doppler shift that
occurs directly towards or away from the antenna.  If the object moves at an
angle to the gun, the shift will be lower than if it moves directly at the
antenna.  Therefore the reading the radar gun gives will be less than the
actual speed of the object.  The radar reading can be calculated by taking
the Actual Speed times the cosine of the incidence angle.  So if the target
car's actual speed is 50 miles per hour and it is 37 degrees off of the
mainline radar signal, the radar speed will be 40 miles per hour. Look:

Cosine Error Theory:
Actual Speed  x  Cosine of Incidence Angle  =  Radar's Shown Speed

Cosine of 37 degrees is 0.80
50 MPH  x  0.80  =  40 MPH

So if you see a radar enabled cop coming head-on towards you it would be a
good idea to get into the right hand lane, or further if possible, as this
increases the angle and thus lowers your radar speed.  The other error is the
Moving Radar Error, which occurs only when a police car is using a moving
radar gun.  A false reading is obtained by the unit because before it
can radar you it must radar something along side the road to get the patrol
car's speed.  Most often, billboards and parked cars are used for this initial
patrol car speed calibration.  It is susceptible to errors because of the
Cosine Error, mentioned above.  Once the patrol car has its speed (wrong or
not), it assumes that the target's (YOU) speed is the difference between the
highest oncoming signal and the patrol speed; but if the patrol speed is lower
it will ADD that error on to the target speed.  So the target speed (YOU) will
read higher than you were actually traveling.  Here's the theory and a
problem:

Moving Radar Theory:
Closing Speed  -  Patrol Speed  =  Target Speed

The ACTUAL speeds for these are:
Patrol Car Speed - 60 MPH
Target Car Speed - 60 MPH
Closing Speed - 120 MPH

Due to the Cosine Error the TARGET CAR's speed will cause the gun to
calculate a LOW reading for the actual patrol car's speed due to the cosine
error.

The RADAR calculated speeds are:
Patrol Car Speed - 50 MPH
Target Car Speed - 70 MPH
Closing Speed - 120 MPH

Thus you can see how the police car is going to get an incorrect reading.
This is a good one to memorize and bring into court for any tickets.

   It's been recently brought to my attention that there are stealth-bras for
cars.  From what I understand, the bras actually absorb the radar, and reflect
such a weakened signal that the radar gun cannot detect it.  I have not seen
one of these in person, but from what I have heard they are made out of a VERY
DENSE rubber/metal composite.  The bra probably traps the signal very much
like the F-117/B-2 stealth aircraft do.  The material is probably made up of
hexagonal shaped cells, the back of the cell being at a slight angle, so that
any signal coming into the cell will have to bounce around within the cell
before exiting it.  The inside of each cell is filled with a radar absorbing
material.  As the signal hits the back of the hexagonal cell it is bounced
around inside the cell through the absorbing material, weakening the signal
each time it does so.  Upon leaving the cell, the signal is so weak the
radar's receiver may not pick up the signal until the target is near enough
to give a positive return on the radar screen.  When the aircraft is getting
closer, within radar range, the signal reflected may be so small the radar's
controller may think he is picking up ground interference, a flock of birds
or possibly bad weather.  The actual radar absorbing material is classified at
this time by the government.  The actual composite on the car bra is certainly
not as good as the actual radar absorption material of the aircraft, but I'm
sure it is somewhat similar.

   Radar jamming is done very much the way any other type of radio jamming is
done.  You simply overpower the frequency being used with a frequency of your
own.  Radar jamming/overpowering is ILLEGAL in the United States.  To jam a
signal all you need is a transmitter, an amplifier and an antenna.  To jam a
gun using a K band radar (24.150 GHz) all you do is get a transmitter that can
transmit in the 20 GHz range and a 10-100 watt amplifier and antenna.  Send
out a signal at around 24.05 GHz.  This signal will make the cop's radar
either show a 0 or an incredibly slow speed such as -520.  Usually the
cop's radar cannot show a negative sign, so it will just be 520.  This
10-100 watt signal that you are transmitting will overpower the signal
his/her radar sent out and is waiting to receive.   His/her gun is only at
100 milliwatts, and you're transmitting at 10-100 watts; its like using a
12-gauge shotgun against a rodent.

   Where can you get microwave transmission equipment?  You can check local
electronic shops, satellite stores, Cable TV companies and local television
stations as to where they buy their microwave transmission gear.  Or you can
buy a radar gun of your own, and leave it ON whenever your driving.  This will
give the cop's gun a very strange reading, most likely zero. If it is
possible, once you have the gun bring it to a "corrupt" electronics shop and
have it modified for high powered transmission, preferably in the 10 to 100
watt range.

   Some radar guns have resistors implemented just before the antenna, but
just after the amplifier for de-amplification of the transmitter's signal.
This means that most guns already have a good (1 watt or so) transmit
capacity, but it is suppressed to bring the actual transmit signal to the
100mw area.  The owner of the gun only has to know which resistors to take
out, then he/she will have a functional high powered gun.  If this small
wattage does not satisfy you, you may have to purchase a separate amplifier
for the gun, and have it wired directly into the radar's transmitter antenna.
This modification is expensive not to mention illegal, but then again what the
hell isn't these days.  I have seen six different types of guns offered from
National Radar Exchange.  The following are a few major radar gun
manufacturers that are sold out of most radar shops. They are:

KUSTOM SIGNAL:
Kustom Signal HR-12  K Band 100mw signal 2000-3000 foot maximum range $695.00
Kustom Signal HR-8   K Band 100mw signal 1800-3000 foot maximum range $495.00

CMI INC.:
Speedgun One  X Band 100mw signal 1000-2500 foot maximum range $395.00
Speedgun Six  X Band 100mw signal 1000-2500 foot maximum range $495.00
(Since these units are the same, the only differences are things like
last speed reading recall, 10 number memory, etc.)

MPH INC.:

MPH K-55  X Band 40mw signal 1200-2500 foot maximum range $495.00
(Can clock target in 1/2 second, which is exceptionally fast for radar guns)

The only differences between the models are their bands and their options,
such as a "HOLD" button, last speed recorded etc.

   I have found these to be some of the top units in the radar detector world
   currently and are listed as follows:

MOST SENSITIVE   MOST FEATURES   BEST LOOKING   MOST RELIABLE    SMALLEST
--------------   -------------   ------------   -------------  -------------
COBRA 4120       COBRA 4120      Whistler 3SE   ESCORT         Uniden RD-9XL
BEL 944          COBRA 3160      BELL 944       K40            Whistler 3SE
Snooper 6000     BELL 944        Uniden RD-9XL

 BEST VALUE         LOUDEST           BEST FILTERED
------------     --------------    ------------------
Snooper 4000     COBRA 5110        Snooper 6000
Cobra 5110       COBRA 3120        Other Snoopers
Cobra 3168       Whistler Q2002
Maxon RD25

   I did not get to see Cincinnati Microwave's new "SOLO", nor BEL's
"Vector 3", "Express", nor it's newer "Legend 3."

Just because a detector is the MOST sensitive doesn't mean it is the best
detector.  Because of the sensitivity you could pick up more alarms.  What
you want is a detector with excellent sensitivity, but good anti-falsing
circuitry.

   I hope this article has given you some insight on how radars work and
how their tickets CAN be defeated.  Keep safe and sane,

                                               Professor Falken
                                                Legion Of Doom


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