radar proof? or imagined
Melting Slicks
Joined: Nov 2005
Posts: 3,323
Likes: 142
From: Green Valley Arizona
Originally Posted by 87laker
We should be clear about a couple of points. First there are two commonly used speed detection devices used by traffic police; Dopler radar and Laser. They work on totally seperate principals. Dopler radar sends out a signal which bounces off your car and returns to the radar antenna. The signal is simular to a radio wave. The time it takes for the signal to return is manthmaticly converted to speed then displayed in the squad car. Most radar signals are not sent out until the officer sees your car speeding and activates a standby button. There is no way to avoid the signal. Jamming devises work well against Dopler radar but or illegal in most states. Getting caught with a jamming device can be very costly. People on byicycles can be clocked by radar so any car, regardless of it's shape, makes a good target.
Lasers send out a beam of lader light which is returned to the unit and then mathmaticly converted to speed. Since it is light and not a radio wave, it needs to be "reflected back". Reflective license plates and glass make it much easier to reflect the laser light and this is where officers like to aim it. Less target area can make it harder to get a reading, but not impossible. No front plate with lights down = less target area.
Lasers send out a beam of lader light which is returned to the unit and then mathmaticly converted to speed. Since it is light and not a radio wave, it needs to be "reflected back". Reflective license plates and glass make it much easier to reflect the laser light and this is where officers like to aim it. Less target area can make it harder to get a reading, but not impossible. No front plate with lights down = less target area.
Okay, enough of the science talk
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Originally Posted by LannyL81
Actually lasers and radar work on the the principal. What we call light is an electromagnetic raditation...same as what we call radio or radar waves or signals. Rador and laser radar both use doppler to measure speed or velocity. Doppler is the compression or lengthing of a reflected signal which causes a frequency shift. It is this frequency shift that is measured and then the velocity is calculated. Both radar and laser use reflected energy, both electromagnetic energy.
Okay, enough of the science talk
Okay, enough of the science talk
Laser speed measuring devices do not use the Doppler effect to measure speed. Laser guns send a series of light pulses and times the successive round trip time to calculate and display speed.
Melting Slicks
Joined: Feb 2006
Posts: 2,753
Likes: 15
From: backwoods upstate ny
a while back, we bought a ''sport'' radar gun to check our boats (low profile jets, no windshield, 6-71 blower sitting way up)...our radar would give no reading of a boat coming at it...got a leo to try his unit, same nothing...going away from the radar would read every time (rear of the boat is flat)....get two boat bow sections and put one on each end of your car and you're good to go.
Racer
Joined: Dec 2004
Posts: 306
Likes: 0
Originally Posted by C4DC
Dave Mc Llelan mentions this in his book about the C4. Basically their radar showed a reading when the car was half the distance away comparing to other cars.
you are correct. i have the same book and thats in there, and dave expalins why its harder to pick up the corvette on a radar.
Last edited by jeffyc; Sep 22, 2006 at 11:15 PM.
Race Director
Joined: Sep 2001
Posts: 14,674
Likes: 751
From: NEwhere Ohio
Originally Posted by IRAraid
But if you get pulled over and have a detector on your dash, you'll get a ticket instead of a warning every time.
Simple solution to that is to quickly disconnect the radar detector/throw it behind the seat if you see a cop 'whipping around' on you or pulling out to get you.
If you do it right away you'll usually have enough distance on him so that he doesnt see you do it.
IMHO if you arent aware enough of your surroundings to notice that a cop is turning around or coming out after you, you shouldnt be on the road.
Race Director
Joined: Sep 2001
Posts: 14,674
Likes: 751
From: NEwhere Ohio
I have gotten a ticket from a 'rear shot' of radar at my car. 36 in a 25? or something like that. Dunno. to me it felt like noraml driving?
Anyways. I have noticed that sometimes speed signs will not get a lock on my car even though im the closest to the sign. instead they will lock on a taller vehicle behind me. Its funny because I can slam on the brakes, accelerate, etc. and the speed sign will do nothing. It will just report the higher vehicle behind me's speed (in some cases 1/8 mile away!). Sometimes at the last second it wil get a lock on me when im directly in front of the gun.
Anyways. I have noticed that sometimes speed signs will not get a lock on my car even though im the closest to the sign. instead they will lock on a taller vehicle behind me. Its funny because I can slam on the brakes, accelerate, etc. and the speed sign will do nothing. It will just report the higher vehicle behind me's speed (in some cases 1/8 mile away!). Sometimes at the last second it wil get a lock on me when im directly in front of the gun.
Safety Car
Joined: Feb 1999
Posts: 3,504
Likes: 4
From: Mexico Beach FL
Originally Posted by jfb
Laser speed measuring devices do not use the Doppler effect to measure speed. Laser guns send a series of light pulses and times the successive round trip time to calculate and display speed.
Police radar uses the Doppler effect to measure speed.
Laser does not use Doppler -- it times the reflected laser light.
Tom Piper
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Originally Posted by Jack_leg
Talking about sound and radio waves are the same as far as energy. When you think of sound that you can that you can hear and radio waves that you can’t its just because they are at a different frequency. So, in a nut shell, you being the nut, sound and radar, or (radio) are all the same within respect of energy. So, lay off unless you have a physics degree.
If you want, Google a book on radio waves and physics.
Also, I do agree, if you speed, and you look like your speeding, it doesn’t matter, it will be a ticket. So give up on it unless you’re just really bored and want to look like a fool. Sorry to be harsh, its just facts.
Race Director
Joined: Jun 2004
Posts: 13,957
Likes: 706
From: WI
Originally Posted by Corvette Kid
You could redo your bodywork in "stealth" technology!
Melting Slicks
Joined: Apr 2003
Posts: 3,110
Likes: 6
From: Red Sox Nation! RI
Originally Posted by IRAraid
But if you get pulled over and have a detector on your dash, you'll get a ticket instead of a warning every time.
The local police here have a mobile radar detector that they frequently park on the side of the road. It's mounted on a trailer and has a large LED display of your speed. I don't know what band radar it uses, but every car I've driven by it was dead on for accuracy, including the vette.
Burning Brakes
Joined: Jun 2005
Posts: 1,189
Likes: 13
From: Wallingford Vermont
FWIW, Interfering with (this case jaming) any radio frequency is an FCC (federal) violation. Radar is a radio transmission. Although the FCC also grants you the right to recieve any radio transmission. Some states have used old laws that prohibit the use of a radio reciever during a crime (is in it self a crime) to prohibit the use of a radar detectors. 
REAL radar jammers work, but... 
Now Laser is part of the light spectrum and not afforded protection under the law (federal, at least). It can be jammed too, legally and effectively.
For some of the more recent information on both I suggest everyone take a gander here:
http://www.speedzones.com/
The new test results are out!
REAL radar jammers work, but... Now Laser is part of the light spectrum and not afforded protection under the law (federal, at least). It can be jammed too, legally and effectively.
For some of the more recent information on both I suggest everyone take a gander here:
http://www.speedzones.com/
The new test results are out!
Last edited by DanZ51; Sep 23, 2006 at 03:29 PM.
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Originally Posted by DanZ51
FWIW, Interfering with (this case jaming) any radio frequency is an FCC (federal) violation. Radar is a radio transmission. Although the FCC also grants you the right to recieve any radio transmission. Some states have used old laws that prohibit the use of a radio reciever during a crime (is in it self a crime) to prohibit the use of a radar detectors. REAL radar jammers work, but...
Now Laser is part of the light spectrum and not afforded protection under the law (federal, at least). It can be jammed too, legally and effectively.
For some of the more recent information on both I suggest everyone take a gander here:
http://www.speedzones.com/
The new test results are out!
REAL radar jammers work, but... Now Laser is part of the light spectrum and not afforded protection under the law (federal, at least). It can be jammed too, legally and effectively.
For some of the more recent information on both I suggest everyone take a gander here:
http://www.speedzones.com/
The new test results are out!
Team Owner
Joined: Jan 2006
Posts: 26,598
Likes: 0
From: Hampton, VA Yea, i'm a redneck... but you love it
Cruise-In 8-9 Veteran
aka/Trunk Monkey/Banned For Life/Corvette For Life
Originally Posted by Tom Piper
jfb is correct.
Police radar uses the Doppler effect to measure speed.
Laser does not use Doppler -- it times the reflected laser light.
Tom Piper
Police radar uses the Doppler effect to measure speed.
Laser does not use Doppler -- it times the reflected laser light.
Tom Piper
Burning Brakes
Joined: Dec 2003
Posts: 1,183
Likes: 1
From: MidOhio
Originally Posted by C4DC
Dave Mc Llelan mentions this in his book about the C4. Basically their radar showed a reading when the car was half the distance away comparing to other cars.
What I'd like to see is some tests on metallic painted C4s versus non-metallic painted ones. I'm betting the metallic paint significantly increases the radar signature with silver the highest. Anyone ever read any data on this aspect?
Burning Brakes
Joined: Dec 2003
Posts: 1,183
Likes: 1
From: MidOhio
Originally Posted by redrose
a while back, we bought a ''sport'' radar gun to check our boats (low profile jets, no windshield, 6-71 blower sitting way up)...our radar would give no reading of a boat coming at it...got a leo to try his unit, same nothing...going away from the radar would read every time (rear of the boat is flat)....get two boat bow sections and put one on each end of your car and you're good to go.
The car mods you mention sound like the Aero Vette concept car! 
Burning Brakes
Joined: Dec 2003
Posts: 1,183
Likes: 1
From: MidOhio
Originally Posted by DanZ51
FWIW, Interfering with (this case jaming) any radio frequency is an FCC (federal) violation. Radar is a radio transmission. Although the FCC also grants you the right to recieve any radio transmission. Some states have used old laws that prohibit the use of a radio reciever during a crime (is in it self a crime) to prohibit the use of a radar detectors. REAL radar jammers work, but...
Now Laser is part of the light spectrum and not afforded protection under the law (federal, at least). It can be jammed too, legally and effectively.
For some of the more recent information on both I suggest everyone take a gander here:
http://www.speedzones.com/
The new test results are out!
REAL radar jammers work, but... Now Laser is part of the light spectrum and not afforded protection under the law (federal, at least). It can be jammed too, legally and effectively.
For some of the more recent information on both I suggest everyone take a gander here:
http://www.speedzones.com/
The new test results are out!
Yep! 
The old laws are probably what the repressive state of VA is using to ban radar detectors! 
Burning Brakes
Joined: Dec 2003
Posts: 1,183
Likes: 1
From: MidOhio
Originally Posted by jfb
I don't need a book on radio waves and physics because I have already been through both, enough to have a BSEE. Radio waves can travel in a vacuum, but sound waves cannot. With respect to energy, sound and radio waves are not the same, sound waves have zero energy in a vacuum. I recommend you find some good books on radio waves and physics.
Burning Brakes
Joined: Dec 2003
Posts: 1,183
Likes: 1
From: MidOhio
Originally Posted by dizwiz24
I have gotten a ticket from a 'rear shot' of radar at my car. 36 in a 25? or something like that. Dunno. to me it felt like noraml driving?
Anyways. I have noticed that sometimes speed signs will not get a lock on my car even though im the closest to the sign. instead they will lock on a taller vehicle behind me. Its funny because I can slam on the brakes, accelerate, etc. and the speed sign will do nothing. It will just report the higher vehicle behind me's speed (in some cases 1/8 mile away!). Sometimes at the last second it wil get a lock on me when im directly in front of the gun.
Anyways. I have noticed that sometimes speed signs will not get a lock on my car even though im the closest to the sign. instead they will lock on a taller vehicle behind me. Its funny because I can slam on the brakes, accelerate, etc. and the speed sign will do nothing. It will just report the higher vehicle behind me's speed (in some cases 1/8 mile away!). Sometimes at the last second it wil get a lock on me when im directly in front of the gun.