radar and laser jammer

Jamming a laser range/rate detector would probably be out of the question for that kind of money and product available market served. Frequency modulating a signal to jam
Terahertz light frequencies with a radar carrier frequency of 10's of Gigahertz ain't gonna do it.

Now if you want to not only jam, but tell the police radar what speed you want them to read, that's relatively simple. A technique I used many years ago is called Baseband jamming. While I used it on X Band radar (10.525 GHz.), it is easily scalable to the higher frequency bands now in use.

What radars do is broadcast a pure signal out at relatively low power (10's to 100's of mW) and some small fraction of the signal that bounces off of your car is then recieved by the radar unit shifted in frequency by an amount proportional to the speed you're going. At X Band, this Doppler shift was 31.4 Hz/MPH at 10.525 GHz. To get the difference, a small portion of the tramsmitted signal is diverted inside the unit and the mixed with the recieved, frequency shifted signal. The output of this mixer would then provide the sum and difference signals. The lower frequency, difference signal would be the 31.4 Hz/MPH. As an example, 100MPH would yield a mixer output frequency of 3140 Hz. This is easily converted, being in the same range as audio, to read out MPH by simply dividing by 31.4 in this case.

The jammer I designed took advantage of a given fact (take my word on this one) that the radar's mixer will output the sum and difference of two input signals in the face of pure un-amplitude modulated signals. If we were to provide a radar signal in the same relative power range and relatively close (no need to be exactly on his 10.525 GHz carrier, the front ends of these things are crude)to his frequency,and amplitude modulate (turn on and off the signal) at a rate of 3140 Hz in this example, he'd read not the difference in frequency between his transmitted signal and the reflected signal (very, very faint as most of it is reflected all over the place, not back into his antenna), but the much more powerful signal that your pointed straight at him with. What will then happen in his mixer is that it will then act like what is called an AM detector and output only the 3140 Hz that you are sending him. The difference frequency that he thinks he's looking at will be completely overridden by the amplitude modulated signal that you're nailing him with at thousands of times the signal amplitude that his reflected signal is coming back.
Conveniently, there just happens to be an Amateur Radio band near where you want to be at 10.250 GHz. which will work just fine. (Sorry officer, but I was just trying to work some X Band traffic for the VHF contest).

So you're in your M5 doing 150 MPH and this cop looks at his radar that shows 55 MPH (or whatever you decide to set your jammer speed at). In another scenario, you're sitting up on an overpass at a specific time that you know a particularly arrogant guy in an E55 is getting out of work, going the speed limit and on the other side of the overpass is a speed trap. You program your trusty jammer to output the equivalent of 150 MPH and the rest is history.

For a more "permanent" solution, get a hold of a piezo electric crystal material sometimes used in sonar applications. It's called Lead Zirconium Titinate. When shock excited it produces an extremely high amplitude pulse as it is destroyed. The frequency of this pulse is determined by the size of the cavity it is mounted in. So you have a machinist mill you out a cavity in a block of aluminum whose dimensions correspond to the frequency of the radar you want to jam. Next get a hold of a 22 caliber starter's pistol and machine the barrel to screw into this block. The opposite end of the block is open and you simple place a small 1/2" square piece of this crystal maybe 1/8" thick in the cavity, then put a piece of masking tape over the square hole so it won't fall out. Screw a small horn type antenna on the front of the block, load the pistol with a 22 blank cartridge, aim and fire. 100+ Megawatts for a couple of microseconds will render any radar's mixer diodes permanently kaput instantly within a range of 200 yards.
Of course the sound of a gun going off 200 yards from a cop might result in a jail term or returned fire, but at least he won't be using that radar for awhile.

Honestly folks, these two methods really do work, but like anything else, common sense in their application (or not) is key.

Regards,
Doug

damn Roton, it's so simple!

Now where were you 6 months ago when I was seriously considering it? Correct me if I'm wrong, but radar jamming is illegal nation-wide (or maybe it's just here in CA). I know that laser jammers are ok, but CHP doesn't use lidar in the first place.

--Dan

As far as the availability of the jammer, to my knowlege none have ever been really on the market. The ones that I built back in the early 80's, I did from scratch. Basically, the only part that's not available from standard sources is the microwave transmitter itself, but I believe you can easily get them today from any number of sources listed in Amateur Radio magazines. The unit is called a Gunn Oscillator (the word Gunn is the name of the guy who discovered the principles involved in the workings of the Gunn diode used in this ocillator), and most of these units were made by a company called MaCom in Burlington, MA. I believe they were distributed by a company called Whitehouse, Inc. Gunn Oscillators were available in both X and K Band variants. They are small (X Band unit had a waveguide flange about 2"X2" and was about 1.5 inches deep, the K Band unit was slightly smaller). Small 10 dB gain horns were also sold for them. I believe back then that they sold for something in the neighborhood of about $100.00 each.

The X Band unit is powered by 10 Volts, the K Band I think was about 7.5 Volts. When you power then up, the oscillators put out their respective frequencies. Each has a small piston type mechanical tuner that lets you adjust their frequency. As I said before, this isn't critical as police radars have very broadband front ends. If you merely turn on and off the oscillator at different frequencies, you will transmit the required AM signal. So what you put in front of the oscillator is a pulse generator that you can adjust from say 314 Hz (10 MPH at X Band) to 3140 Hz (100 MPH at X Band). By building a simple audio frequency synthesizer, you could even have it readout what speed you programmed rather than having to convert frequency to doppler shift in your head.

Well, I'm on my way out the door to Arizona so I'll catch you all later.

Regards,
Doug

So Roton, I guess what he's saying is, "You wanna build some of those again for a select clientel?"
Dude, I'm in!
Mark

oooh oooooh oooooh oooooooh oooooooooh

i want one too.

fas

Something I thought you may want to read for future reference.


Microwave Jammers

ECM -- Electronic Countermeasures
From time to time traffic radar jammers appear in magazine ads and such (the Internet). Be aware MOST, if not ALL, of these jammers are useless (absolutely no effect at any range under any conditions) based on test reports by Automobile magazine, Car and Driver, RADAR Reporter and Truckers News. The legality of jammers is also in question and somewhat up to the whims of bureaucrats and politicians (local, state, and federal) regarding enforcement and court interpretation of the law. Several U.S. states and some countries prohibit the use or possession of a jammer.

For the United States FCC (Federal Communications Commission) to consider an intentional radiator legal the field intensity (power) must meet FCC limits (Rules Part 15) AND the device must perform some function for the public good. Traffic radar jammers are not considered good for the public by the FCC.


The FCC considers the use of traffic radar jammers as malicious interference and strictly prohibited by the Communications Act of 1934, as amended, as well as by FCC rules. Anyone using a jammer risks such penalties as losing FCC licenses, paying a fine, or facing criminal prosecution (from FCC Public Notice -- FCC Regulates Radar Transmitters, but not Radar Detectors, DA 96-2040, 1996 DEC 9) .
Passive jammers are suppose to re-radiate the radar signal after distorting it (adding noise and/or rapidly shifting frequency) in such a way the true target reflection is masked by the distorted signal. A passive jammer does not generate or amplify a signal, only channel or redirect the radar signal (after distorting) back toward the radar. For this method to work the jammer (distorted signal) power must be as large as or greater than target reflected power -- the jammer antenna would need to capture well over half of all the radar energy striking the target (a very large jammer antenna), and be aligned to the radar antenna. To date all known passive jammers have absolutely no effect on any radar under any circumstances.

On 4 December 1997 the FCC ruled passive jammers violate federal regulations because the jammers radiate RF (Radio Frequency) energy that (or is intended to) adversely affect the ability of law enforcement officials to protect public safety on the highways. The ruling was based on a passive jammer (Sprint II) made by Rocky Mountain Radar (out-of-business) in Colorado. Before this ruling passive jammers were not considered transmitters and thus not covered by FCC regulations.

Active jammers either detect a radar signal before transmitting (jammer must have fast reaction time), or continuously transmit whether a radar signal is present or not (less sophisticated jammers). Many traffic radars can detect jamming signals (alerting the radar operator) even when the radar is not transmitting, this is why a jammer should only transmit when a radar signal is present.

A variety of jamming signals, depending on jammer, are used to blind (noise jamming) or fool (deception jamming) traffic radar. Transmitting brute force noise is one technique used to obscure target echoes; however this may be detected by many radars as a jammer signal alerting the operator. Another technique is to transmit a signal (fake target echo) at a frequency that will get into the radar Doppler discriminators/filters. The signal appears to the radar as a legitimate target overriding the real target echo; then the jammer signal will drift in frequency slow enough for the radar to track and too fast/erratic for the radar to calculate speed (effectively blinding the radar with no indication to the operator). The jammer signal could also force the radar to a set predetermined frequency that causes the radar to read a speed (set by the jammer). These last two techniques depend on knowing the EXACT frequency transmitted by the radar and generating exact (very tight tolerance) frequencies for transmission.

Most traffic radars have some ECCM (Electronic Counter-Countermeasures) capabilities for detecting, alerting the operator, and countering Radio Frequency Interference (RFI) and jamming signals. The degree of success a radar has detecting and countering an unwanted signal varies with unwanted signal parameters, range between transmitter and radar, and radar make and model.

To date only one known (active) jammer actually works; the Stealth/VRCD made by Stealth Technologies in Naperville, Illinois -- reported (June 1998) to be out of business due to an FCC crackdown on radar jammer manufacturers. This jammer counters X and K band traffic radars; some later models reportedly also counter Ka band (fixed frequency) radars. The unit has an audio alert and LED to indicate when a radar is detected, and another LED to indicate the jammer is transmitting. The unit reportedly uses a fake target echo to blind the radar (as described in the above paragraph). This jammer received high marks from Car and Driver magazine, RADAR Reporter, and Truckers News. The RADAR Reporter (1993 NOV edition) tested the Stealth/VRCD against 5 different radars; 4 out of 5 radars could not register target speed at all. In all cases the radars gave no indication a jamming signal was present. The Decatur MV-715 (X band) managed to measure target speed (burn-through the jamming) on one test run, at a mere 150 foot range (will vary with target radar cross section). The jammer managed to detect and defeat the traffic radar in plenty of time and long enough for a driver to react (if necessary).

Yupkwondo:

Thanks for the info, I think laser jammers are slightly different from radar jammers though?

Dan:

I haven't noticed a significant increase in false alarms on the V1 since installing the K40 laser jammer. My V1 does false on laser occasionally, perhaps a dozen times in the past few years.

I have not had the experience of the K40 laser jammer going off yet so clearly, there is no laser signal leakage from the V1.

I don't think the V1 and the K40 laser jammer ever interfere with each other.

However, I have heard of stories where the xenon lights from the M5 may interfere with the K40 laser jammer but to me, that doesn't seem like a big issue - as long as you add an on/off switch to turn the K40 jammer off at night with the xenons, you're all set.

For me on the E55, the V1 works beautifully with the K40 laser jammer.

Out of the two, I find the V1 much more valuable. The directional indicator on the V1 is a must, it tells you whether the cop is in front or behind. It also has better sensitivity on radar signals than the full K40 laser/radar detector so I only opted for the K40 laser jammer.

Yes, the K40 built in look is nice but I rather have superior detection. My friend's K40 radar detector could not even pick up photo radar vans which I find quite pathetic. The V1 is great, instead of letting off the gas looking around like an idiot, its directional indicator will tell you whether to look in front or at the mirror.

I have had numerous occasions where the cops from the opposite traffic would do a u-turn to pace me, of course, I could pin-point his moves with the V1: front signal getting stronger and stronger, then I get the side signal together with the strongest front signal as we pass one another. The signal then become a strong rear signal weakening. However, if the rear signal never goes away but starts getting stronger again, I know the same bugger is trying to pull a dirty trick so I set the cruise control at 55mph and wait for him to overtake, glancing at the rear view mirror with a big smile..

To make my V1 as discrete as possible, I also installed the remote concealed unit.

I think one way or another, the Uniden Police Scanner is still a must, that's the only way we can track air crafts when they communicate with the ground troops.. However, I don't travel on the highway enough to justify the cost and the installation hassle of yet another detector!

It's like a war out there doesn't it!