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  1. #1
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    Default when do cops know that we are coming

    i've been wondering when cops know that we are coming. Like once the rd goes off do the cops radar automatically send the info back? is the range of a rd greater than that of a leo radar. I hope I asked this right. Im trying to say that when the rd goes off by the time i slow down does the cop see that i was going like 90 then slow down to 70. and then he doesnt stop me cause i wasnt close enough.

  2. #2
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    In the best of conditions, line of sight against a good target, most radar units can only acquire a speed up to a mile or so away. In the same situation, a high end radar detector can alert to the radar over ten miles away. Even low-end radar detectors can alert to radar a lot further away that the radar's normal target range.

    Without getting technical, here's the main reason for this. For the radar detector, the signal only has to travel one way: from the radar gun to the target vehicle. For the radar gun, the radar has to travel twice as far: first from the radar gun to the target vehicle, and then back to the radar gun. The reflected target signal that the radar gun sees is always much weaker than the signal a detector in the target vehicle sees.

    But when you add in "normal" terrain, with hills and curves, this can reduce your range and response time drastically, so that you might only have a few seconds to adjust your speed before being clocked. And if the officer targets you with "instant-on", then you'll have no prior warning at all until he clocks you, with no time to slow down. To protect against instant-on, you need a detector that alerts to an officer using instant-on on traffic ahead of you, before it is "your turn". These are the reasons why it is important to have the most sensitive detector you can afford, in order to have the most protection.

  3. #3
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    Default

    ok so with me reading that "again". if my radar detector goes off and its only the minimum bar or strength the cop already knows that i was speeding. but the advantage is that if there are more cars around me then he can't determine who he was clocking right? And therefore lets everyone go.

  4. #4
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    Quote Originally Posted by ryansrt4
    ok so with me reading that "again". if my radar detector goes off and its only the minimum bar or strength the cop already knows that i was speeding. but the advantage is that if there are more cars around me then he can't determine who he was clocking right? And therefore lets everyone go.
    I think you missunderstood. If you have a weak alert on your radar detector, chances are the cop did not get a reading on your speed. This is why you should slow down for weak alerts and see if your alert ramps-up to a stronger signal. This is how you know you are aproaching a cop or some other sort of strong radar source. Bottom line is if you get an alert and you're not sure if it is real, you should slow down until you can determine where it is coming from.

  5. #5
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    watch this video:

    Cool user point of view with radar: www.cooleysllc.com/radar101.html



    -

  6. #6
    Speed Demon
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    Default

    Quote Originally Posted by ryansrt4
    ok so with me reading that "again". if my radar detector goes off and its only the minimum bar or strength the cop already knows that i was speeding. but the advantage is that if there are more cars around me then he can't determine who he was clocking right? And therefore lets everyone go.
    How on earth did you come to that conclusion with that great explanation? With the exception of instant on, your detector will always detect the officer before he gets your speed. On the highways you generally have a long time to slow down before the LEO gets your speed. Sometimes miles to slow down. Around curves you will have less time to slow down, but you will have some time.

  7. #7
    Radar Fanatic
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    Quote Originally Posted by CJR238
    watch this video:

    Cool user point of view with radar: www.cooleysllc.com/radar101.html



    -
    you know after watching that i say to myself, no wonder cops use laser more and more. For the accuracy and convenience. Radar is complex to pinpoint exact car and prone to lots of error. So maybe thats why they just dont feel like using it as much as Lidar.

  8. #8
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    I would prefer laser too. I swear i have seen LEO's pull people over for the speed i was going. :roll:

  9. #9
    Suf Daddy
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    What a crappy location for that test.

    Not only is the traffic in each direction so similar a speed, but the telephone poles and the building (house) clutter is just a pin ball machine of multipath feedback signal.

    A better instruction video would of had less clutter and more of a perpendicular (YES PERP), to show when a target (car) goes THRU the beam and when the tone changes. The flutter is a reflection JUST outside of the center of the beam which is competing as/for the strongest signal.

    That vid DOES (IMHO) show WHY police turn off the Doppler audio when using radar.

    To the original post.

    Professor Jim, has it down, but what the noob needs to remember that his reflection of the radar signal needs to overcome the "DIN" or static of the surrounding signal reflections.

    You need to reflect enough of the sent out signal BACK to the antenna for it to get a reading. Weak signal means you have some time to slow down as you get closer and start reflecting a stronger signal back to the radar antenna.

    Hence when you get a really weak (in the EXCEPTION of close proximity POP) signal, odds are your getting the fringe of the LEO's transmission of radar and some one up close is getting a stronger signal.

    Add in once the other vehicle passes through the radar cone of radio energy, YOU *might* be the next strongest signal to produce a reading.

    Until your RD gets to about half strength, odds are you have a chance to slow down.

    The problem is most people TUNE OUT most low level warnings.
    they consider them "junk" or falses, and then as you get closer, a crafty LEO using IO, can IO you at a MUCH closer range and get your speed.

    So the REAL Q is:
    Are you going to "heed" those low level "warnings"? or just blow them off and charge into the ambush?

    IME, a real IO threat is on a deserted Hiway, where there is NO traffic ahead of you for ~2 miles or so, making your time ~120 second (2 minutes @ 60 MPH) to NOT get any warning, while the LEO waits in the median for you to get closer and closer, then IO you.
    Cooked.

    I've had it happen, but been at the PSL so I kept on my way.

    Certain aspects of radar IMHO are more convincing or "true" speed than LIDAR.

    One is that EVERY surface of your vehicle reflects back to the radar as an ENTIRE Doppler shift of radio frequency.

    LIDAR measures distances from ASSUMING that the operator can aim & track the same point of your vehicle during the entire speed reading calculation. LIDAR by operation introduces panning and sweep into determining a reading of speed.

    Doing it by radar is a no brainer.
    -Suf Daddy

    Quote Originally Posted by Event Horizon
    Quote Originally Posted by CJR238
    watch this video:

    Cool user point of view with radar: www.cooleysllc.com/radar101.html
    you know after watching that i say to myself, no wonder cops use laser more and more. For the accuracy and convenience. Radar is complex to pinpoint exact car and prone to lots of error. So maybe thats why they just dont feel like using it as much as Lidar.

  10. #10
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    Default

    ok now i understand. i thought i did before but know its clearer. but one more ? is Instant on and POP the same thing? cause i usually do bout 20 over on my way to work ( 5am very little traffic for being dallas tx) And ive detected pop and it scared the crap out of me cause the rd just goes crazy. but then ive been driving along and seen the leo on side of the road then all of a sudden ka goes crazy is that instant on or did he just decide to turn it on. and that why i got a strong signal ause i was right there. i read somewhere that leo's sometimes use a "proximity radar", that emits a strong signal over a very short distance no more that 1/4 mile. is this is real or just something that i read wrong.
    and if it is real then ould this be confused with IO. If IO and POP are not the same. Hope this makes sense

 

 

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