Police speed radar... does anyone calibrate them?

Started by Squidley, 08-20-2013 -- 07:55:11

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Squidley

08-20-2013 -- 07:55:11
Has anyone out there ever calibrated a cop's radar-gun and  / or it's check standard?
Douglas J. Baird, USN(ret),

Hawaii596

#1
08-20-2013 -- 10:23:49
I have not, and purely from memory, seems I remember someone commenting years ago that it is done with a tuning fork. That was many years ago though.
"I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind."
Lord Kelvin (1824-1907)
from lecture to the Institute of Civil Engineers, 3 May 1883

spanishfly25

#2
08-20-2013 -- 12:27:38
yes, I did them way back.  we use two tunning forks, one was for 55mph and the other I don't remember but was high, like in the 80mph range. the forks we had to send out for calibration to another lab, you tap the forks on the table and they viabrate to make the radar gun read.  but I think the new police guns are laser and not radar

ZZ

#3
08-20-2013 -- 16:13:25
At my last employer we calibrated police radar guns with a computer program. The program emitted whatever frequency we needed for a particular speed. Typically a 4 point cal based on what speed range the guns are needed for. It worked well, but traceability was not exactly "unbroken".

Most of the hand held radar guns I've seen come with a test fork. Not saying our method was any better, but it worked. It really depends on what you or your company are willing to spend if you want traceability.

NC-Cals

#4
08-21-2013 -- 08:11:19
When I was stationed at the lab at the Air Force Academy '85 to '89 we calibrated the radar detectors for the SPs. If memory serves, we opened the unit and injected frequencies in the audio frequency range somewhere in the -100 to -120 dBm range. We also calibrated the tuning forks.

Bill the Cat

#5
08-21-2013 -- 20:06:12
Not the guns, but I have calibrated the tuning forks that are used to calibrate the old style radar guns.  Most of the new ones are laser now and if you work for a police force they almost certainly need to be calibrated.  Most of them get calibrated at a government owned calibration lab, mostly State operated facilities.  The cops don't want the tickets challenged because the guns aren't calibrated.  I work on an Air Force base and the guns they use are called LIDAR (laser) and they have regulations that require them to be calibrated at a lab recognized by law enforcement authorities. 
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