Why not fool a Laser gun with a false speed reading???

[RadarBunny]

The most advance radar jamming technology is the ECM 5446. To see the pic of the unit, please run a google search. I love that unit because it confuses the radar with a false speed display instead of giving out a blank reading.

I really wish the next generation of laser jammers do not require users to turn off the jammers because it gives out a false PSL reading to the lidar gun.

I don't understand why AL and LLP is concentrated on the error code fix. The best way to work around is NOT to jam the gun completely; it is to fool a lidar gun with a false speed reading. :wink:

[Audi Quattro]

i like to yell out my speed thru the sunroof to confuse the laser gun.

[cooljay]

well here's how I see it: How is the Jammer suppose to know the PSL? GPS, sure ok but that just increases the price etc. Also what if there is a construction zone on the highway and a LEO running a laser speed trap when the speed drops but the jammer is still programmed to send the false speed of the PSL not the construction speed limit?

You're looking at a might big ticket there for a device that is suppose to save you. Jamming is better because it gives you time to slow down and for you to switch it off for the LEO to get a reading that doesn't look suspicious where as people would get into the habit of trusting there jammer and then BAM instant-on radar as you pass the LEO running laser but also has a radar unit.

[jimbonzzz]

The most advance radar jamming technology is the ECM 5446. To see the pic of the unit, please run a google search. I love that unit because it confuses the radar with a false speed display instead of giving out a blank reading.

"Dialing in" your speed with the ECM 5446 or similar unit might sound pretty cool.
But in practice, there are some big problems with doing so, one main problem being that you have no way to determine what mode of radar you will be facing. Although the concept works OK for stationary radar, you also have moving radar: same-lane moving mode, or oncoming moving mode. In stationary mode, the strongest doppler return (in this case, the jammer's signal) is interpreted as the target speed, while in moving mode, the strongest doppler return would be interpreted as the patrol car speed.

For example, lets say that your jammer is set for 50 MPH, which is interpreted by moving radar as the patrol car speed:

In oncoming mode, if you're going 90 MPH and the cop is going 70 MPH, the radar "sees" 160 MPH which is your and the cop's speeds added together, then subtracts the 50 MPH false speed the radar thinks the cop is going. The radar will display 110 as your speed.

In same-lane moving mode, if you're going 90 MPH and the cop is going 70 MPH, the radar "sees" 20 MPH which is the difference between your speed and the cop's. Then, it adds the false 50 MPH speed it thinks the cop is going, and displays 70 as your speed.

In theory, one could have a unit that sends a false patrol speed AND a false vehicle speed. But, you would need to do this different for front and rear. In moving mode (oncoming) the higher doppler is interpreted as the return from the target vehicle. But in same-lane mode it is the opposite, the lower doppler freq is the target vehicle return. Just send out the right frequency pair for whatever speed you want to display. And, what about fastest vehicle mode? This gets pretty complex, and the officer might get a bit suspicious if the patrol car speed on his radar unit doesn't match the speedometer.

So in conclusion, it is better to have a fast-varying doppler, so the gun doesn't lock onto any speed at all. :wink:

I really wish the next generation of laser jammers do not require users to turn off the jammers because it gives out a false PSL reading to the lidar gun.

I don't understand why AL and LLP is concentrated on the error code fix. The best way to work around is NOT to jam the gun completely; it is to fool a lidar gun with a false speed reading. :wink:

Laser guns calculate speed my taking a number of distance measurements over time. Jammers work by timing the jamming pulse so that the gun accepts the jamming pulse as it's own reflected pulse. After the gun sends out a pulse, generally the first pulse received is generally accepted as the gun's own reflected pulse, anything received after that is ignored, until the gun sends out another pulse. So generally the jamming pulse must be received at the gun before the gun's own reflected pulse is, in order to be accepted by the gun.

The problem: to display a slower speed then the actual target speed would require the distance measurements to decrease at a slower rate than the actual target distance readings. So, the jammer would need to time the jamming pulses so that the gun thinks that the target vehicle is further away than it actually is. But to my knowledge this isn't possible: If one attempted to do this, the jamming pulses would be received at the gun AFTER the gun's own reflected pulses are, in which case the jamming pulses would simply be ignored, since the gun's own reflected pulse would be received first and accepted by the gun for use in speed calculation.

In theory it might be possible to make the gun display a faster speed than the actual target, but who wants that?

Jim

[fulcrum]

I did exactly this already a few years ago. (My Alfa164 was doing 164km/hr backwards on a Jenoptic LaserPatrol , although it was parked at the end of a street )

But: It only worked on a stationary car that had low reflectivity. (Front licenseplate removed and at a long distance)
I did this with a tweaked prototype using one of my own designed laserjammers. I don't think this is a usable feature on a real laserjammer.
I am working on a universal laser distance measuring device, that by changing the software becomes a perfect laserjammer. The hardware is very versatile, and if you have the optional high-resolution timer hardware board installed the software could be adopted to give false speedreadings. (But keep the above in mind)

[Suf Daddy]

Radar?
Even like Jim said, if you "matched" a speed reading to a return frequency, you'd have NO idea if you were going to encounter X, K Ka, KA wide frequencies BEFORE you get into Moving or stationary.

I bet you'd get burned with a crazy fast ticket on one occasion.

Lidar speed jamming? I seriously doubt it. Far too many details to compute and calculate return pulses in time.

Same as above, like each frequency, each LIDAR gun uses different pulse rates................hence the "look up tables" on some jammers. I bet its an ultra expensive project to prove me wrong on.

Cut down the reflection to the LIDAR gun and you win, cheap and legally too.
-Suf Daddy