The procedure we follow is what the manufacturer specifies, so please keep that in mind as you read this, ok?
Also:
The state of Georgia requires (and I do not have the wording of the law in front of me) that the radar is "calibrated by an FCC licensed technician using instruments that are A) calibrated in the last year; B) hold a manufacturer's assurance of reliability of accuracy;and C) calibrations must be NIST traceable." Each certificate must be witnessed by a someone other than the calibrating technician or the officer using the radar and must be notarized.
So, here we go...
When you test, are these under optimal conditions w/o other automobiles around?
Having any other cars or traffic around doesn't enter in to it! (Surprised? Read on).
If other cars are around, what is the ratio of errors to good readings?
This does not apply, again, read on.
Is the testing done on a mount, hand held, or both?
If mounted, is it in a car or a platform?
The tests are done stationary with the radar unit mounted in the car most of the time.
Do environmental conditions (heat/cold) have any bearing on the longevity of accuracy?
No. No effect on doppler readings unless you are passing the signal thru vast areas of the atmosphere. As you know, traffic radar is a "under a mile" kind of thing. (And in our tests, it's an "under 2 feet" kind of thing.)
How often do these devices get calibrated and how often are they tested for calibration?
You mean my test equipment? Every year they, by Georgia law, are sent to the manufacturer for calibration.
Is the line of sight straight and true?
Sure is. Since it's under 2 feet in the calibration test!
What amount of "surface cover" (if that is the right terminology) is required in order to certify the reading as accurate?
About 3 square inches. (I have your attention now, don't I?)
We do not drive cars at the radar to calibrate them! That would be TERRIBLY inaccurate. Mathematics can tell us just how the radar operates and what we expect to see. (That is part of my long diatribe on traffic radar that I have not posted yet. I can see that I MUST post it now!)
Now, let me describe just what we do.
1) Using an HP microwave frequency counter, we measure the signal's frequency coming out of the antenna to within 1 megahertz.
This measurement is entered on the calibration form.
2) We enter this frequency into a Halyard Traffic Radar Calibrator. We now measure the signal from the antenna using the Halyard. This is to measure the strength of the radiated signal, the thing here is to see if the level is within specifications. This does not impact accuracy of speed readings, but range. Of course, we are also checking to see if it is exceeding licensed or rated power. (They NEVER do!)
3) We now, using the Halyard, choose "tuning fork" mode. We now measure the frequency of the officer's calibration tuning forks. This will be between 3500 and 7000 hertz, depending on the speed the fork is intended to indicate for the frequency that this particular radar operates at.
These measurements are entered on the calibration form.
4) Since the frequency the radar is running has been entered, the Halyard can determine what speed the fork SHOULD indicate on the radar and it displays this speed as well.
This measurement is entered on the calibration form for each of the tuning forks.
5) For each tuning fork:
The tuning fork is excited (we hit it on something) and placed within 2 feet of the antenna. The radar should read the speed from (4) above.
The speed the radar indicates is entered on the form. If the speed does not match exactly the speed in (4) above, the radar fails certification and must be returned to the manufacturer for repairs.
So, what do tuning forks have to do with traffic radar? I assume by your questions, you already know the answer.
For everyone else, it has to do with the "doppler effect", which you can google on line.
I know this is almost an incomplete answer to your questions. Problem is, the explanation, to be complete, of what we do and why involves a bit of math and some RF and doppler theory. I go into that in my diatribe on Radar. I'll post it in a day or two... after I proof it again, ok?
For now, just know that the
RF frequency the radar operates on and the
speed of the car we are watching determine the
doppler shift the radar will see. THIS is why we indicate the frequency of the radar, the frequency of the fork and the speed indicated. We then check to see what the radar reports when subjected to that EXACT doppler shift by the fork. If it does not agree with the math - it fails certification.
It is WAY past time for bed here....