Discussion
A good old fashioned tuning fork.
Calibration is done by striking a small tuning fork "cut" for a certain speed and holding the fork in front of the radar antenna.
If properly calibrated, the radar will indicate the same speed as is stamped on that particular tuning fork. The unit is also checked by pressing a "calibrate" button on the radar and observing the
correct electronic responses indicating that the unit is functioning properly.
Street
>> Edited by Streetcop on Sunday 11th July 10:15
>> Edited by Streetcop on Sunday 11th July 10:24
Calibration is done by striking a small tuning fork "cut" for a certain speed and holding the fork in front of the radar antenna.
If properly calibrated, the radar will indicate the same speed as is stamped on that particular tuning fork. The unit is also checked by pressing a "calibrate" button on the radar and observing the
correct electronic responses indicating that the unit is functioning properly.
Street
>> Edited by Streetcop on Sunday 11th July 10:15
>> Edited by Streetcop on Sunday 11th July 10:24
.it's a strange concept really, (tuning fork), but it's very accurate.. LIDAR such as LTI 20-20 are self calibrating when switched on. They carry out a software check, and won't operate if they're faulty. They're also sent back to the manufacturer at least once a year to be checked/calibrated. This is recorded by the manufacturer in line with their usual proceudres, and there's also usually a calibratiuon sticker on the unit. If this is out of date (although I've never seen one that is), the unit isn't used.
In addition to this, in my Force it's standard practice to do a distance check before using the equipment. We set up the unit and check it over an accurately measured distance ( a paint spot on the floor to a wall). This distance is created using Leica surveying equipment, so it's very acurrate). The display should read 0mph, and the distance should be the same as the measured distance (in our case 50.0m). This check is recorded (as with other equipment tests/checks) in your note book. Additionally, if the mobile camera van is being used, the distance check is also recorded separately.
In addition to this, in my Force it's standard practice to do a distance check before using the equipment. We set up the unit and check it over an accurately measured distance ( a paint spot on the floor to a wall). This distance is created using Leica surveying equipment, so it's very acurrate). The display should read 0mph, and the distance should be the same as the measured distance (in our case 50.0m). This check is recorded (as with other equipment tests/checks) in your note book. Additionally, if the mobile camera van is being used, the distance check is also recorded separately.
kevinday said:
Dibble, I understand your calibration process,
It's not calibration, it's a distance check...
kevinday said:
it does not prove the timing is correct. Should you not test against a moving target as well, such as a police car travelling at x mph?
The target (ie wall) is at a known speed of 0mph. The software bits do the speed/time/distance calculation, measuring the time it takes for the laser light pulse bursts to be returned from the target. You can't have the speed measured without the distance, and vice versa.
Sorry that sounds a bit vague, cabbaged after a weekend tutoring a probationer in traffic stuff...
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