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View Full Version : May be a silly question but...



kkoshko
03-12-2011, 01:48 AM
...if say you just set up your jammers...and you want to know if they even remotely work, could you use a range finder? And if you jam that your headed in the right direction. I mean obviously police lidar guns are more sophisticated than a range finder but i mean there both use laser to get the distance. That's if there is no way you can get your hands on a gun for testing.

KaPro
03-12-2011, 06:33 AM
The only question would be if the range finder is 904nm?

PMoth
03-12-2011, 07:22 AM
Even though a jammer can stop a lidar gun from producing a speed, the lidar gun will still produce a distance when in distance mode at any given time. Knowing this, I can only assume that a range finder will still display a distance.

kkoshko
03-12-2011, 10:52 AM
Even though a jammer can stop a lidar gun from producing a speed, the lidar gun will still produce a distance when in distance mode at any given time. Knowing this, I can only assume that a range finder will still display a distance.

I didn't think that lidar guns in distance mode you could still pick up distance...if your interfering with laser beam why would it be able to pick up distance and not speed then?

krypton2
03-12-2011, 12:29 PM
Some laser range finders have speed reading mechanisms, too...I'm not sure how they would compare to your regular police-use LIDAR guns though, as far as the wavelength and time to get a speed...

Newcon has a few of them, I know Simmons has one or two. Bushnell might actually make one but I'm sure it's extremely expensive.

I've actually wondered this same question before...testing against a laser range finder that's used in hunting or sports really serves no real life purpose as it's not what you would encounter police using in the field...but I've wondered if jammers could accurately jam it anyway.

yellowcab
03-12-2011, 12:30 PM
Your jammers will probably not respond to a range finder.

kpatz
03-12-2011, 01:06 PM
Jammers won't jam distance readings on lidar guns. This is because only a few pulse returns are needed to get distance (in theory, only one, but typically the gun will use several in succession to ensure an accurate reading).

Guns compute speed by taking several distance readings over time and determining speed by computing the change in distance over time. Jammers work by causing erratic readings during this process, thus making it look like the car is further away on one reading and closer on another, so it can't get a good plot of distance/time (which should be linear if the car is going a constant speed).

Plus the jammers don't have algorithms for jamming range finders. They can still be used to test the detection side of a jammer and an IR camera (or cellphone camera) can verify the heads are firing, but that's about it.

CJR238
03-12-2011, 01:11 PM
...if say you just set up your jammers...and you want to know if they even remotely work, could you use a range finder? And if you jam that your headed in the right direction. I mean obviously police lidar guns are more sophisticated than a range finder but i mean there both use laser to get the distance. That's if there is no way you can get your hands on a gun for testing.

Ideally test using what your up against. If your local LEO's use range finders than fine, otherwise its a waist.

If i wanted to see what the 0-60mph is on my car i wouldn't use my bike to find out. Because it can be quite possible that though your jammers alert they may not be jamming. Do whatever you can to test against what your up against. If its not possible its just a roll of the dice ether way.

kkoshko
03-12-2011, 01:39 PM
Jammers won't jam distance readings on lidar guns. This is because only a few pulse returns are needed to get distance (in theory, only one, but typically the gun will use several in succession to ensure an accurate reading).

Guns compute speed by taking several distance readings over time and determining speed by computing the change in distance over time. Jammers work by causing erratic readings during this process, thus making it look like the car is further away on one reading and closer on another, so it can't get a good plot of distance/time (which should be linear if the car is going a constant speed).

Plus the jammers don't have algorithms for jamming range finders. They can still be used to test the detection side of a jammer and an IR camera (or cellphone camera) can verify the heads are firing, but that's about it.

thanks for that i guess i never really knew how lidar guns got speed, but that does make sense.

kkoshko
03-12-2011, 01:40 PM
...if say you just set up your jammers...and you want to know if they even remotely work, could you use a range finder? And if you jam that your headed in the right direction. I mean obviously police lidar guns are more sophisticated than a range finder but i mean there both use laser to get the distance. That's if there is no way you can get your hands on a gun for testing.

Ideally test using what your up against. If your local LEO's use range finders than fine, otherwise its a waist.

If i wanted to see what the 0-60mph is on my car i wouldn't use my bike to find out. Because it can be quite possible that though your jammers alert they may not be jamming. Do whatever you can to test against what your up against. If its not possible its just a roll of the dice ether way.

i have a police buddy who wants to test, so i'll just do it that way!

CJR238
03-12-2011, 02:02 PM
i have a police buddy who wants to test, so i'll just do it that way!

Perfect,:o Do the first few runs with the jammers off so he gets PT (play up the disappointment), then ask if you can try shooting your car and turn the jammers on before he gets in. ;)

upstatedoc
03-12-2011, 03:40 PM
i have a police buddy who wants to test, so i'll just do it that way!

I can't believe you just said this. Do not do this. Do you want your buddies' buddies to learn how to defeat jammers and then pwnt you?

category4
03-12-2011, 04:39 PM
i have a police buddy who wants to test, so i'll just do it that way!

I can't believe you just said this. Do not do this. Do you want your buddies' buddies to learn how to defeat jammers and then pwnt you?

X2, do not show your police buddies anything. First step toward getting them banned and you are training them how to defeat these systems. Let him get his training on his own. Don't be an idiot an spoil things for everyone else.

There are plenty of enthusiasts around with guns to test with. If none in your area get a few others with jammers and split the cost on a rental.

CJR238
03-12-2011, 06:54 PM
I think he was joking, similar to me. :)

OpenRoad
03-12-2011, 07:16 PM
I think he was joking, similar to me. :)

X2 - I got it. I was about to post the same joke, but the OP got it in first.

kkoshko
03-12-2011, 07:37 PM
come on guys one big rule is never talk! after i show him maybe i can set up event for all the surrounding cities ;)

g_jammer
03-13-2011, 09:54 PM
When I target my LI Dual equipped vehicle with my PLIII in range only mode (at 100' or more), what I see is a wide range of distance measurements displayed by the LIDAR unit, and the unit will not lock onto a correct distance.

Being that distance manipulation is the heart of a LIDAR counter measure, I would expect a similar result from any 904nm range finder with a sufficiently long pulse rate to allow the counter measure to influence the result.