General question about Laser

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05-31-2007, 04:21 PM
rks

General question about Laser

I'm sure this has been covered on the forum, but I can't find it. Basically, my question is if your RD gets a laser hit, is it safe to say that you've already been shot and it's most likely too late already to slow down. I was watching some videos by another member on this site, I think his name is Jason. (Great vids btw). When he was messing w/ those LEOs, it seems that as soon as his RD picked up on the laser that the LEOs already had his speed since the LIDAR gun can pickup at over 3000 feet. Also, what exactly is punch through. Thanks.
05-31-2007, 04:43 PM
jimbonzzz

Re: General question about Laser

Quote:

Originally Posted by rks

I'm sure this has been covered on the forum, but I can't find it. Basically, my question is if your RD gets a laser hit, is it safe to say that you've already been shot and it's most likely too late already to slow down.

In most cases, yes. But there are some exceptions.

Quote:

Originally Posted by rks

I was watching some videos by another member on this site, I think his name is Jason. (Great vids btw). When he was messing w/ those LEOs, it seems that as soon as his RD picked up on the laser that the LEOs already had his speed since the LIDAR gun can pickup at over 3000 feet. Also, what exactly is punch through. Thanks.

Punch-through (n) - When using a laser countermeasure, the point at which the countermeasure is no longer effective and a speed reading is obtained by the targeting laser gun. Usually expressed in units of distance, such as feet.
05-31-2007, 08:34 PM
maskellxx

Re: General question about Laser

Quote:

Originally Posted by jimbonzzz

Quote:

Originally Posted by rks

I'm sure this has been covered on the forum, but I can't find it. Basically, my question is if your RD gets a laser hit, is it safe to say that you've already been shot and it's most likely too late already to slow down.

In most cases, yes. But there are some exceptions.

Quote:

Originally Posted by rks

I was watching some videos by another member on this site, I think his name is Jason. (Great vids btw). When he was messing w/ those LEOs, it seems that as soon as his RD picked up on the laser that the LEOs already had his speed since the LIDAR gun can pickup at over 3000 feet. Also, what exactly is punch through. Thanks.

Punch-through (n) - When using a laser countermeasure, the point at which the countermeasure is no longer effective and a speed reading is obtained by the targeting laser gun. Usually expressed in units of distance, such as feet.

The exceptions he is talking about is, if, the car in front of you or to the side of you is being hit, sometimes you can pick it up before you are the target.
05-31-2007, 09:03 PM
NY946

Your RD picking up the laser hitting a target vehicle in proximity is rare, but not by any means impossible.

Think about how large the beam is at 1000' from the gun: Approx 3' in diameter.
At 2000: Approx 6' in diameter.
At 3000: Approx 9' in diameter.

So if your "neighbor's" car is about 6' wide and he is shooting from 1500' or so, the chances are slim that your RD will pick it up.

Either way, it is safe to assume that if your RD goes off, the LEO has your speed. Side with caution, or just drive the speed limit... :lol: :roll: :wink:
05-31-2007, 09:16 PM
Stealthcb

Quote:

Originally Posted by NY946

Your RD picking up the laser hitting a target vehicle in proximity is rare, but not by any means impossible.

Think about how large the beam is at 1000' from the gun: Approx 3' in diameter.
At 2000: Approx 6' in diameter.
At 3000: Approx 9' in diameter.

So if your "neighbor's" car is about 6' wide and he is shooting from 1500' or so, the chances are slim that your RD will pick it up.

Either way, it is safe to assume that if your RD goes off, the LEO has your speed. Side with caution, or just drive the speed limit... :lol: :roll: :wink:

Aren't those numbers dependent on the gun being used? I'd seen some numbers that said the beam was 9-10 in wide at 1500'.

Look at it this way -- when I was driving a rented PT cruiser on I-87 just north of Albany, NY, I got hit with LIDAR. My RD was on the dash and gave me an alert. Yes, he already had my speed. But the LEO was no more than 1000' from me, at most. He was probably targeting my plate or headlights, both of which are more than 3-in from my RD's laser sensor.

Remember -- light bounces off things, so just because the beam is only so many inches wide doesn't mean your RD won't alert. Just fire a laser pointer at your linoleum floor for proof. It not only reflects at an obtuse angle, but DRASTICALLY widens the beam. When i shoot a pointer at the floor at a 45-deg angle, I get reflection on my wall a few feet away the size of a flashlight.

So if you have VEIL on your plate and lights and aren't THAT much over....

And I have twice gotten LIDAR skip off other cars, so it's not THAT rare. The important thing is to not be first in line, and to keep your head on a swivel.
05-31-2007, 10:03 PM
Suf Daddy

Scatter and some other situational influences may exist.

The LIDAR 3 milliradian divergence (spread) yields these approximate 3' @ 1,000 ft figures we hear about.
Their beam pattern is more important here IMHO.

As NY946 points out a 3,000 foot shot, ~5/8 of a mile, is a HUGE surface area of refractable light. This just simply is MUCH larger than the profile of you vehicle.

AS for scatter, I can get a concentrated beam of LIDAR within feet of a RD sometimes without tripping it.
.........and then aim away from the RD and get a refraction from a power line that sets of the detector..........

I've even lit up a street sign POST ~10' off the post and the scatter refraction was enough to trip a distance reading...........

Last week I encountered my first Infinity "Laser" guided cruise control.

Straight line sight to me: RD goes off
Slight curve or traffic pulls in between them and I? RD is quiet...........

-Suf Daddy

Quote:

Originally Posted by NY946

Your RD picking up the laser hitting a target vehicle in proximity is rare, but not by any means impossible.

Think about how large the beam is at 1000' from the gun: Approx 3' in diameter.
At 2000: Approx 6' in diameter.
At 3000: Approx 9' in diameter.

So if your "neighbor's" car is about 6' wide and he is shooting from 1500' or so, the chances are slim that your RD will pick it up.

Either way, it is safe to assume that if your RD goes off, the LEO has your speed. Side with caution, or just drive the speed limit... :lol: :roll: :wink:
05-31-2007, 10:08 PM
Suf Daddy

They are. While most LIDARS in the US make the 3 milliradian spread / divergence with different size optical lenses, one exceeds that (per the manufacturers specs........)

That older LIDAR is ~ 4' @ 1,000 and its beam pattern orientation is different too..................................

-Suf Daddy

Quote:

Originally Posted by Stealthcb

<<SNIP>> Aren't those numbers dependent on the gun being used? I'd seen some numbers that said the beam was 9-10 in wide at 1500'.
06-01-2007, 06:05 PM
Rabbiter2

Re: General question about Laser

Quote:

Originally Posted by rks

I'm sure this has been covered on the forum, but I can't find it. Basically, my question is if your RD gets a laser hit, is it safe to say that you've already been shot and it's most likely too late already to slow down.

And the answer is... The "do nothing" option is your absolute worst action. If you are hit by laser the correct action is to kill the excess speed as quickly as possible. Jam on the brakes, do whatever is appropriate in the circumstances to return to the legal limit. If you are in luck the hit is a false positive or you are picking up scatter from another target. Your turn to take the hit is next and by then you are back to the legal limit.

Remember, laser targeting can be very quick. So you need to react really quick too. If you have to first ask yourself, "What do I do now?", its probably too late to do anything.

There are other defenses against laser. For example, drive in a pack in known laser areas. In that way you can let the vehicles ahead alert you to the presence of a laser trap. Or invest (?) in a good laser jammer. I find that with a good laser detector and following the advice here, I have yet to be nabbed by laser.