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Thread: Invisible to a radar gun

  1. #1
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    Invisible to a radar gun

    If you knew the frequency used by a radar gun and had a coating that would make the reflectivity drop to near zero @ that specific frequency, on command.......would you car zip right along undetected? Maybe if you hitch up with these Turks......SEE : https://arxiv.org/abs/1801.05051

  2. #2
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    I don't know for sure, but I'd be surprised if the radar guns used these days operate at a single frequency. From what little I've heard, due to a few speeding tickets over the past few years, radar guns are pretty difficult to fool and most of the "myths" about how to do so don't actually work. Though they apparently do need to be calibrated at some regular interval.

    If a coating could somehow drop reflection back to the source to zero, then I don't see any reason that the vehicle wouldn't be undetected. Though I might be missing something. But not even the B-2, F-22 or F-35 achieve zero reflection back to the source. How much is this car going to cost? Will the coating be applied to the windows, tires, interior, lights, license plate, trims, seams between body panels and dissimilar materials, grille, etc.?

  3. #3
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    A pretty detailed summary of literature on police radar gun frequencies

    It looks like there a couple of different bands they use, but I don't get the impression that a particular gun varies the frequencies.
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  4. #4
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    Thanks for inspiring me to actually look at some data Swift. Should have done that before.

    Another source I looked at, http://copradar.com/chapts/chapt1/ch1d1.html, had this about Ka band radars, the most common, that is on topic.

    "Many models have a channel bandwidth of 100 MHz, a 200 MHz wide channel. Some models have a bandwidth of 50 MHz, a 100 MHz wide channel. The Ka-band has multiple channels (frequencies). Most Ka band police radars operate on one frequency channel, a few have 2 channels an operator can select."
    Apparently lidar is starting to replace radar for law enforcement speed detection

  5. #5
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    Quote Originally Posted by Darrell View Post
    If a coating could somehow drop reflection back to the source to zero, then I don't see any reason that the vehicle wouldn't be undetected. Though I might be missing something. But not even the B-2, F-22 or F-35 achieve zero reflection back to the source. How much is this car going to cost? Will the coating be applied to the windows, tires, interior, lights, license plate, trims, seams between body panels and dissimilar materials, grille, etc.?
    I was lamenting the demise of the F-14 Tomcat, in a "How could This Be?" sort of way. (I spent a lot of time working on their radar and fire control systems.) I was at the beginning of their fleet service. I was contacted by a former F-14 pilot from the last operational squadron.

    Normally a, AWG-9 radar system can lock up an airborne target at 110 nautical miles out, and well enough to fire a missile at it.

    At full power, 1/4 mile off the tail of a F-22, he got *nothing*. He only knew it was there because he was looking at it.

    So while technically you are correct, there is that big bugaboo of "insignificant figures".
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  6. #6
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    Big Don. Yep. pete

  7. #7
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    Do the police still use radar in the USA?

    In the UK the switch was made to laser units years ago, they are far more accurate and discriminating. Radar can be confused by other moving vehicles and reflections from street furniture.
    Fixeroadside Gatso camera units still use radar and the similar but newer Truvelo unit uses magnetic detection loops in the road. More modern systems use a system of automatic number plate recognition cameras that calculate average speed between pairs of units.
    To foil Radar a company was selling a kit that claimed to be device for remotely opening garage doors but it was really an active jammer. When Laser came along they started selling an optical jammer that confuses the laser unit.
    It's obvious whey they are usedthough, the officer using the unit can't get a valid reading on your car. If you are found with one fitted to your car you are prosecuted.
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  8. #8
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    Quote Originally Posted by captain swoop View Post
    It's obvious whey they are usedthough, the officer using the unit can't get a valid reading on your car. If you are found with one fitted to your car you are prosecuted.
    I just use the Waze app.

    Let the other thousand drivers in front of me warn me about cops ahead (and accidents and construction and jams).

    In fact, it's kinda cool that, by the reports of other users, you can actually see the tactics of waiting police. Cop parked here, 40 minutes ago. Cop 500 yards farther, 25 minutes ago. Cop 500 yards farther ahead of that, 10 minutes ago.
    Last edited by DaveC426913; 2018-Feb-04 at 05:55 AM.

  9. #9
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    Camera Van positions for the day are posted on the police web site, they don't tell you exactly where or when, just the road they will be on and a general area.
    It keeps everyones speed down.
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