Police Laser Gun - Pro Laser II

**TgaGuy** · 9th May 2008, 18:42

Originally Posted by Pixie

I have had a Laser jammer for several years,which I am confident does work.
I base this on confused looks from cops as I pass them and it was tested against a laser gun at Radar Direct.
Being a curious fella I looked at back engineering the jammer.
I found it seemed to leak a 4 MHz signal,so I assumed it was pulsing it's 9 IR LEDs at this frequency.This would generate a false reading fixed at around 38 metres from the laser gun.

I have produced a prototype that pulses 12 IR LEDs at 4 MHz.All I need now is a gun to test it against.

http://www.radar.co.nz/usa/usechofaqs.html FYI

Laser Echo confuses the speed calculation by sending "echo" pulses into the laser gun between its own pulses. The remote-mount laser unit (transponder) has both a photo diode (detector, receiver) and a laser diode (transmitter, emitter). When the detector "sees" the first pulse from the speed gun, it triggers the laser diode to fire back a pulse train, but at a much higher rate than that of the laser speed gun. Since the laser wavelength in both devices are the same, Laser Echo's signal is accepted by the gun. The computation of speed is then delayed because the laser gun receives information it considers inconsistent.

**vagrant** · 9th May 2008, 18:59

Originally Posted by TgaGuy

I was waiting for some flares to go off on the Herc when i targetted it,but nothing happened.

They would have just pushed a Unimog out the back. Clock that!!!!

**CookMySock** · 9th May 2008, 19:18

Originally Posted by TgaGuy

When the detector "sees" the first pulse from the speed gun, it triggers the laser diode to fire back a pulse train, but at a much higher rate than that of the laser speed gun

I wonder how the jammer "aims" its laser at the speed gun ? Coz if its not pointing right at it, then it might as well be pointed straight up.

DB

**sAsLEX** · 9th May 2008, 20:02

Originally Posted by vagrant

They would have just pushed a Unimog out the back. Clock that!!!!

Be a pretty small Mog!

A LAV might fit in with flat tires.....

**vagrant** · 10th May 2008, 11:04

Originally Posted by sAsLEX

Be a pretty small Mog!

A LAV might fit in with flat tires.....

Unimog 1700L (standard army issue job) fits in piece of piss. Did it on Monday.

Twice.

Lav fits in with out deflating tyres. If you let the tyres down, it makes the track too wide for the dual rail mechanism for the cargo pallets.

**sAsLEX** · 10th May 2008, 16:38

Originally Posted by vagrant

Unimog 1700L (standard army issue job) fits in piece of piss. Did it on Monday.

Twice.

Hmm I aint believing that without pictures, I would of said a standard MOG is way too tall......... oh they are 3.14m roughly http://www.army.mil.nz/our-army/equi...nt/default.htm

And a C-130 load bay is

Just a touch short since 9 feet = 2.7432 meters

Can a Herc make it across the ditch or anywhere with a LAV inside?

**Mikkel** · 10th May 2008, 22:03

Originally Posted by DangerousBastard

I wonder how the jammer "aims" its laser at the speed gun ? Coz if its not pointing right at it, then it might as well be pointed straight up.

DB

The laser guns used for speed measurements are battery powered devices...
As such you can count on the power emitted being fairly modest.
Combine this with the fact that the reflection that the gun is to pick up off the car comes off a curved surface - thus, only a small fraction of the emitted power is reflected back and picked up by the detector. Consequently the detector will registrer and "accept" a low-energy pulse.

On the other hand, the jammer is hooked up to the cars electrical system and can use a significant amount of power to strobe pulses at the detector. It doesn't need to "aim" to be effective - a space angle of 180 degrees (a quarter of a sphere) is sufficient.

**sAsLEX** · 10th May 2008, 22:16

Originally Posted by Mikkel

On the other hand, the jammer is hooked up to the cars electrical system and can use a significant amount of power to strobe pulses at the detector. It doesn't need to "aim" to be effective - a space angle of 180 degrees (a quarter of a sphere) is sufficient.

Hence why the one Pixie took apart had multiple LEDS so there emissions patterns overlap....