I know what your saying about the Dopplar effect (I just got my mechanical engineering degree). Maybe I should have went Electrical (but then I would probably have to drive an Electric truck and not a gas guzzler jk)

I think the theory I read about involved motion sensors, the kind that set off radar detectors in the cities. I will have to do some internet research to find out some directions. Have you had any problems with radar detectors near buildings with automatic doors or alarm systems?

My next question would invovle those licence covers for your plates. Someone tried to tell me that police need a flat surface to 'bounce' the waves off of and this usually round clear plastic cover deflects the waves away from the radar reciever. . .sounds like BS to me considering the size of the vehicle compaired to the size of the plate.

 

Got some in the Navy, but I'm a radar training officer, and have been called to court to testify about other officer's testimony, as far as some of the technical aspects. The state law and other case law only states that the officer has to know how to set up, test, and operate the radar. But if some lawyer starts to ask a bunch of questions, you have to be able to fend them off and hope the district attorney isn't sleeping so he can object to the question.

Last trip we took we went to Atlanta with the SCrew. No FOP or cop decals, HOG license plates, and kept the speed like 10-15 over. Passed a lot of people, got passed by a lot of people, but the only cop we had any contact with was in SC, and he followed us off the slab when we went for gas and wanted to see the truck.

The license is used as a target for LIDAR, or laser detection. Same effect, only measuring the frequency shift of the light beam. It will work off most any surface, but the flatter and more reflective, the longer range you get nailed at. WE don't use them in Virginia (YET!)

Interesting note: We played with the radar on the SCrew, my wife's vette, and our motorcycles. This will boggle ya....the vette got picked up first, then the Road King, then the SCrew, then her Sporty. Big reason is the HUGE radiator in the Vette, behind the fiberglass. The motorcycle has all kinds of flat spots that reflect well, while the SCrew has the fine lines, and not a lot of flat spots up front. Did this on the private road where we live, with the sensitivity turned down. As soon as I got a reading, the wife threw a chalk mark on the ground. the FLHR got it about 10 ft further away than the truck. Not very scientific, but just an experiment on a boring Sunday.

 

Just a little clarification on Lidar: The time of flight of the pulses are multiplied by speed of light and the resulting distances are plotted as a function of time. A least square fit is used -the slope gives the car speed, and the variance gives a validity test. Radar uses the doppler effect (phase shift) due to the speed of the radio frequency. Successive RF beams cannot accurately calculate speed (low sample rate), due to the low population of transmit/receive beams. Laser travels at/near the speed of light (around the world 7 times in one second) and allows for a larger sample and greater accuracy. 1st beam of laser is "base" shot. Each successive beam is a time/distance calc based off the initial reading of the 1st beam. Doppler could have been used in laser, but the "multiple shot" method is so much more accurate.

Yes, military training for me - fiber optic/radar system tech for USMC. White light shot through a 2 K-meter cable will slow so much that it will come out red on the other end. We shoot a light down a broken cable to find the exact location of a broken fiber cable. That's the accuracy of laser. Also, radar/lidar are most accurate within 10-degrees of the target object. Skewing beyond this, you must use the law of cosines (your speed on radar is actually slower than your actual speed - NEVER use this in court for your defense!).

 

Got the message Valentine 1 should be in my office in the morning. Learned a wealth of knowledge on how radars work. Thanks for the info.......................

 

Good luck with it. Keep the shiny side up, and watch them bears!!! ;-)