Laser gun speed reading
#21
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Originally Posted by ro11dice' post='546524' date='Mar 18 2008, 12:28 AM
Yeah, I'm still a little puzzled by TexaZ3 comment about taking the front plate off. I re-watched the vid and clearly there is some difficulty in obtaining a reading off the windshield or hood. But a few cars don't have front license plates in the vid and got a reading (1st car and I think 3 to last). Notice the motorcycle too. There is some difficulty but there is a lock...but I don't think bikes have front plates, do they? I agree with Imola...flat surface to return the beam.
Comments found in radars and laser gun detectors forums, that mentions they targeting on plate.
"Laser Speed Guns emit a very narrow, intense beam of "invisible" light. The speed of light is a known constant (approximately 300,000 Km per second). Therefore, the laser speed gun calculates distance by measuring the length of time it takes for the beam to travel to a target and back to the gun. Many such readings are taken over a brief period of time to determine how fast a vehicle is traveling. The speed reading "can" be accurate under "ideal" conditions. It is "claimed" that the narrow beam makes target verification more certain than with radar. The Lasers used by enforcement authorities in Australia are made in the USA by Kustom or LTI and operate on a frequency of 904 nanometers. In the states and territories of Australia, Laser Speed Guns have replaced most hand-held radar guns for stationary "point-and-shoot" traps."
"The narrow beam (less than 1 meter at 300 meter from the laser gun) makes target identification more certain than radar under some conditions.
It also makes detection by Radar/Laser Detectors very difficult.
Halogen car headlights and driving lights reduce the range of the Laser Speed Guns.
Refraction errors can produce incorrect speed readings. Because light is refracted differently by hot air than cooler air, a spot of air rising from the roadway can confuse the laser.
Laser beams can be affected by atmospheric conditions. Speed reading range is reduced on cloudy or foggy days.
When the laser beam bounces off more than one solid object (stationary or moving) reflection errors occur, producing an incorrect speed reading. "
"It's a proven fact. Portable Radar/Laser Detectors (all of them) are less than 100% reliable at detecting "short-range" laser hits. Why? The beam is often too narrow to "strike" the laser sensors inside the dash/screen/visor mounted unit. At 300 metres from the Laser Speed Gun, the beam (laser pulses) is approximately 1 metre (100 centimetres) in diameter. It fans out from a very narrow point of transmission. At 200 metres from the Laser Speed Gun, the beam is about 40 centimetres in diameter. Aimed at the front license plate, the top edge of the laser beam barely reaches the bottom of the car's windscreen"
#22
Originally Posted by nicke60gre' post='546544' date='Mar 17 2008, 03:00 PM
"...Halogen car headlights and driving lights reduce the range of the Laser Speed Guns."
#23
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Originally Posted by nicke60gre' post='546424' date='Mar 17 2008, 08:44 PM
What the hell ... ?!
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