Police Lazers

[scumdog]

Apparently they aim for the numberplate. Us lacking numberplates (On the front anyway..) perhaps they don't even try.

Eh? I can't even see the number plate at the ranges I get them at (You ever tried to see a number plate at over 100 metres away and how small it looks?)

BTW C.B. has a Laser and I'm a Police, does that count??????i

[scumdog]

I was waiting for someone like you to pipe up. I will need remove the headlights and wear camo..

Camo? that is the best surface to aim for when using a Lazer!!!

(After the headlight)

[madboy]

Yeah, cops have been nice to me with the guns. Are all of those guns laser, or are some radar? I've never been sure. Either way, none of them have bothered to chase me (I think).

Last one I recall was funny, here I was at 140ish up an 80 zone on the way to work one morning (little goat track called Ngauranga Gorge if anyone knows it). Come round the corner, saw the cop pointing the gun thingey at me. Oh dear, hit the picks and started going down gears. I can't remember if I had the plate on. Down to about 80ish, 2nd gear, still looking at him as I crawl past in the outside lane. He puts down the gun and looks at me. I'm thinking I'm about to get to work 30 seconds quicker, but no, he just sits there. I put that one down to discretion.

[N4CR]

These are 'laser' guns with a single infra red emitter. iR frequency LASER (not radar..) has some rather weird properties, for example an iR beam laser can be deflected to not cause eye damage (by burning of the retina) with a simple perspex shield, where as with visible lasers (take 532nm greenies for an example) you need a filter. iR lasers can also be killed with a filter.

The iR laser, depending on collimation (how straight parallel the beam is, eg not cone shaped) will determine how far away the laser can strike before it becomes too long to get a lock, on a very circular surface the return would be quite weak due to a wide reflection, so a busa might be hard to lock onto etc. That b/s about bikes being easiest to pick up that the police told you is not true, think of it as shooting a gun... bigger the target the easier it is to find a reflection.

One thing I can tell you - heat waves on the hot roads in summer (over a long distance) might have an effect depending on how iR wavelength laser passes through it, i'll get scumdog etc to answer that one.

I don't know enough about iR LASERs to tell you what you need to beat it apart from a jammer, but I will endeavour to find out.

[scumdog]

One thing I can tell you - heat waves on the hot roads in summer (over a long distance) might have an effect depending on how iR wavelength laser passes through it, i'll get scumdog etc to answer that one.

I don't know enough about iR LASERs to tell you what you need to beat it apart from a jammer, but I will endeavour to find out.

I always try and get a high spot on a hot day, that way there's no worries about heat waves etc.

Most cars I get a good reading at about 400 metres, bikes it's down to 300 or maybe a little less - doesn't matter 'cos they still never spot me anyway.

[madboy]

doesn't matter 'cos they still never spot me anyway.

Dirty old men hiding in bushes... I don't know... what is this world coming to?!

[MattRSK]

Must of met his Quota.

[Morepower]

Has anyone tried this stuff??

http://www.laserveil.com/

[GIXser]

They had no problem locking on to me at 121km/hr on my way to town a while back. Hidden under a tree in shadow the guy just stepped out and waved me down. Thought he was a farmer or something (i live in the wops).
Gave me a ticket despite me telling them where the person they were actually looking to get, lived. They'd had complaints of a blue xr6 speeding insanely.
Worst part was I got pulled over a week later and the cop who was a good guy (let me off) told me he would have never given me a ticket as bikes can go way faster than 120+...

Moral of the story is" dont stop for any cop" so, this also means you hide your plate and airbrush it (with a bit of dirt), seriously why stop!!?? they will never get you anyway,,(or simply dont have a plate at all)

[GIXser]

I was waiting for someone like you to pipe up. I will need remove the headlights and wear camo..

None of this is neccesary of you have a speedy bike, a cop car will do
"What" tops 200 K ,,,,,,take off is slow, and to get up to speed is even slower, ,,,by then you should have lost em, if not "get a new bike"

[Sparkz]

The reason they aim at the number plate is that it is a retro-reflector (it relects light back to it's source instead of at an angle equal to the incident light from the normal).

The lasers are 905nm infrared and send out very short (5ns) pulses at 1kHz. The beam diverges (spreads out) as it gets further away and is a vertical stripe (a pulsed laser diode produces a stripe, not a dot) about 1m wide at 1km.

The infrared light will relect off any surface (some more than others), but most surfaces scatter the light and it is very weak by the time it gets back to the laser gun. Retro-reflectors (like the white or red rectangles fitted to the front and back of bikes, and number plates) direct all the energy they receive right back at the source.

Trick is to get rid of any retro-reflectors from the front of the bike. Infrared filter film over the headlight may help too.

Laser jammers use laser diodes pointing out the front of the bike (hopefully right at the laser gun) and send out a stream of pulses at a much higher rate than the 1kHz the police lidar uses. This is interpreted as noise.

[GIXser]

I always try and get a high spot on a hot day, that way there's no worries about heat waves etc.

Most cars I get a good reading at about 400 metres, bikes it's down to 300 or maybe a little less - doesn't matter 'cos they still never spot me anyway.

Saying that your a cop is one thing, however "You actually get a kick out of your "little" laser gun,,

[scumdog]

Saying that your a cop is one thing, however "You actually get a kick out of your "little" laser gun,,

'Ah, the first fish for the creel.......................'
The true sign of a new member is a post like the above. heh heh heh!!!


Of course you could always try my and see how I "handle" my "little" laser

[cowpoos]

Lol that stuff cracks me up.

Radar Jammers dont work

how much do you wanna bet dude....

Your bosses been talkin crap AGAIN

[N4CR]

Hey dynamytus, basic physics state that if you can transmit out an inverse wave at the frequency of either radar/laser source (depending on what is shooting) then the waves will cancel out to a flat line (eg no return) if you take doppler into affect. It is tricky but it is do-able. Would also seem a bit dodgy and warrant for a roadside check for 'emitters'
I seem to remember seeing full on laser jamming setups... the 'blinder' was it?

Or else you can transmit a false wave reflection at a greater power back (than the emitter would reflect at) and mimic the return - one that says you are travelling at less speed than registered on the gun, as it uses the doppler effect to 'guestimate' speed. I can remember reading that some trees and other inanimate objects were tracked at 30-60kmh...

edit: and what sparkz said about retro-reflectors... forgot to post about that the first time.