What should I know about radar and laser jammers?

Some drivers aren't content with just using a detector to detect when a law enforcement officer is using radar or laser to track their speed - they insist upon attempting to "jam" the measurement device so that it returns either an illegible reading, or no reading at all. There are a number of jammers on the market that are designed to jam either radar or laser guns. If you're interested in radar detectors, please visit the Radar and Laser Detectors FAQ.

The contents of this FAQ are taken from a series of articles written by Michael Charness for the Ferrari Club of America newsletter. His articles are reprinted here with his permission.

Radar Countermeasures (June 1995)
Virtually every Ferrari owner I've ever talked to uses a radar detector, but still bemoan the traffic ticket(s) they got when the detector didn't give them enough warning. Radar guns bounce microwave Doppler signals off a car and measure the change in the signals' frequency to determine your speed. The radar detector recognizes that it is being bombarded by an X-, K-, or Ka-band or laser signal and lets the driver know. Modern radar guns can "see" about a half mile (often less but sometimes more depending on road and weather conditions). It used to be common for a patrol car to leave a radar gun on, watching the road and the gun readout for speeders. Most detectors warn of radar signals well over visual limits, before an officer has you in his sights. More often now an officer uses a hand-held unit and doesn't turn it on until he can actually see his target, usually about 1,000 feet or so. This is called "pulse" or "instant-on" radar, and by the time a detector tells you it's in use, you've already been clocked.

So what can you do when you're out for a country drive? You can use a radar scrambler/jammer - legally! They "fool" the radar gun with a distorted signal so that it will not register a confirmed speed, and instead shows zero or nothing at all. That "masking" or "shielding" can give you extra seconds.

There are two types of legal radar scramblers on the market today: active jammers and passive scramblers. Passive radar scramblers receive the radar signal, mix it with electronic noise and reflect it back to the radar gun. Response time is essentially immediate - about a thousandth of a second - and because of the flow-through nature of the scrambler, it isn't regulated by FCC frequency transmitter rules - isn't actually a transmitter. Scramblers claim to provide between 5 and 15 seconds of masking at 60 mph, working on X, K, and Ka frequencies, and are normally less than half the price of active jammers.

Active jammers work in one of two ways. Old designs just blasted out electronic noise on all of the frequencies used by radar guns (simultaneously triggering radar detectors in the vicinity), but the best of today's jammers are designed to sense, scramble and rebroadcast on the exact same frequency it is receiving. Generally, the jammer sends back a seemingly legitimate signal that simulates a target that is rapidly decelerating and then accelerating at rates so extreme (such as zero to 500 mph and back to zero in less than a second), the radar gun goes into a loop and never achieves or displays a confirmed speed reading. This is better than wideband noise broadcasting, which doesn't optimize at the particular frequency used by the radar gun in front of you.

The "intelligent" jammers focus all their power on the exact frequency needed at the time. Since the transmitter's power is below FCC-established limits, designers/manufacturers say that their active jammers are FCC-legal. Although radar guns use the X- and K-bands, the FCC also allows general public and private use of these bands; for example, supermarket self-opening doors and burglar alarm motion detectors operate on these frequencies. The FCC controls and regulates the use of electrical devices that emit beyond a certain power threshold (500 microvolts/meter @ 3 meters, roughly equivalent to 30mw at the device), and the legal jammers stay at or below that threshold, so no licensing is required. But in an article in the October 1993 issue of Automobile magazine, FCC spokesman John Reed disagreed. "There's no way we're going to approve it," he said, referring to one of the jammers. But we were able to test these now, because here, a year and a half later, the FCC has still done nothing visible to limit the manufacture and sale of such devices. However, just as Virginia and the District of Columbia outlaw radar detectors, states can also outlaw active jammers even though the FCC doesn't. An informal survey by Radar Reporter newsletter found that only Illinois, Oklahoma and Iowa have state laws prohibiting use of jammers.

An effective active jammer provides up to a mile of shielding but current models only work on X- and K-band. Manufacturers indicate that the addition of Ka ("wideband" and "super-wideband") masking with today's technology would have to double the $400-$600 that units go for today. However, X and K account for over 95% of all radar guns in use.

Combined with your scrambler or jammer, it is critical to use good radar detection, because detectors have a longer effective range than any shielding device, and therefore warn you of radar monitoring well in advance. This is not a problem for a passive scrambler, since it doesn't broadcast radar signals on its own. An active jammer designed to broadcast constantly on a wide band of frequencies, will set off any normal detector close by. The better jammers which sense, scramble and rebroadcast on the exact same frequency they are being hit with have an integrated radar detector that tells the jammer what to do and when to do it. Today's active radar jammers all claim to have this smart scrambler mentality and contain integrated radar detectors, though they would be expected to have a somewhat lesser warning range and effectiveness compared to high-end stand-alone detectors such as the BEL, Cobra, Passport or Valentine.

I decided to test the units most advertised by actually running them through a radar gauntlet. The most commonly seen passive scrambler is the Mirage 2001 and a unit was graciously provided by Phantom Technology/Jammers Inc. (800-451-4477) for our testing. We found three active jammers being widely advertised: Phantom Technology's Phantom, Rocky Mountain Radar's Avenger, and the Interceptor from Advanced Radar Components (ARC). The Phantom and Avenger are still in development as of this writing (May '95) and not yet in production. Advanced Radar Components (800-949-7539) has been shipping their Interceptor for some time, and sent us a unit right out of existing stock. Engineers at both Phantom Technology and ARC were very helpful in discussing design considerations and test scenarios.

Radar guns for use in our testing were provided by Radar Sales (612-557-6654), who have a wide variety of new and refurbished radar guns for sale to the public. For our test setups we used two police model radar units representing the mid and modern range of what you might encounter on the road. An MPH-Industries K-15 X-band radar gun was used to represent a typical modern stand-by-the-patrol-car-and-point unit, and a old Decatur MV-724 K-band two-piece setup was used as an in-car, dash-mounted, high power unit. Both were used stationary at roadside attempting to clock an oncoming 1984 308 GTSi. First we baselined the distance capability of the guns against the unprotected car at the time of each test series; on the clear 1-mile stretch, the K-15 consistently clocked the car at one-half mile, and the MV-724 was able to get it at 7/10 mile. We then made multiple runs toward each radar gun at 40 to 100 mph with either the scrambler or jammer active. We were looking to compare relative effectiveness, or shielding range, of each of the units under similar test conditions. We did not attempt to develop a matrix of time/speed/distance masking for each unit, since radar effectiveness, and also shielding effectiveness, is affected by local geography, ambient weather conditions and frontal/target signature of each individual vehicle. We just wanted to know if these latest models worked as advertised.

Some recent independent literature has slammed passive units as being no more effective than "putting a box of Kleenex on your dashboard." Since technology is always advancing, we wanted to see for ourselves, as well as provide a comparison of a passive scrambler with the more powerful active jamming units. The Mirage 2001 is by far the most advertised of the passive units, and is the successor to the Eclipse (which was also sold as the Illusion), originally designed by Mike Churchman at Rocky Mountain Radar. The Mirage circuitry is similar to it but with a larger antenna, and reportedly much improved quality control of the manufacturing process. Phantom Technologies provided me test instructions with sample test results, and I fully expected to be able to duplicate them. We started with the X-band K-15 radar gun which was able to clock the 308 at exactly the same point and continued to read it right up until the car passed by. The speed reading on the radar gun never even blinked. I swung around. Another pass at around 50 mph produced the same result. The radar clocked the Ferrari every time, all the time, at any speed. The test button on the Mirage produced the friendly self-test chirp which says it's working fine. We then tried it several times against the K-band Decatur radar gun, again not a blink in the speed reading. I called the folks at Jammers Inc. and they rushed out a second unit for us to test. This time it sporadically blanked out the lower-powered X-band gun, causing an off-and-on effect, providing about 20% protective coverage (totaling around 6 seconds) over the gun's range, which does fit into the ad's claim of 5 to 15 seconds, though you have to recognize that's within a 30 second coverage area at 60 mph, and they don't fall all at the beginning of that range. Unfortunately, the Mirage 2001 still had no effect at all on the high powered Decatur unit. The Mirage sells for $249.95 from a variety of sources, and comes with a 30 month warrantee.

At $595.00 the Interceptor has several features that stand out from those its competitors are publishing about their yet-to-be released products. ARC advertises computerized alignment testing and road testing of 100% of all units before shipment to ensure consistent quality production and performance. The 5.2"x3.2"x2.2" units, though boxy looking, are completely digital with surface mounted circuitry and are Intel microprocessor controlled. Front panel switches and indicators are all flush mounted and include a power switch/on-indicator, a dimmer switch for night operation, and X and K indicators with signal strength for the radar detector function. The volume control for the different audio alarms will go as high as 90db. The unit has a self-test which lashes all indicators and beeps. It sports RDD/VG2 immunity for those states that use radar detector detectors.

A couple of days before the test, ARC contacted us because the unit they had sent was suspected of being improperly calibrated, so they would send us a second one. On test day, we decided that we might as well check out both units on separate passes. In testing against the K-15 first, the Interceptors' detectors came on and started the jamming circuits well before we were in the tracking range of the police radar gun. And, most impressively, in our test against the K-15, both of the Interceptors kept the gun from ever getting a reading on the car (for the full half mile range the K-15 was capable of) until the car was actually passing it!

Against the longer-range, higher-power Decatur MV-724 K-band, however, it didn't fare as well. The first unit didn't sense that it was being hit with K-band radar signals until it was very close to the radar gun, due to the possible miscalibration. The second unit's detector did better, but still usually didn't notice and activate against the K-band radar until the last 4/10 of the 7/10 coverage distance. In only two of the many passes did the gun have a reading on the Ferrari for only a couple of seconds before blanking; the rest of the time we were on the gun's readout for the first 40% of the coverage area (equivalent to 18 seconds of reading and 24 seconds of masking at 60 mph). The company's claim of radar detector sensitivity range of "1 mile or more" seems overstated. Their reason? We were told that, in contrast to most radar detectors, the Interceptor is tuned to look for "real" audio Doppler signals, not just any stray microwave signals it may encounter. It's rare to get a false signal when going by a market with the Interceptor - other than audio Doppler police signals, only close, very strong microwave signals will set it off. Personally, I'd rather have more range and be willing to put up with occasional falsing, but the trade-off still isn't bad. By the time you read this, ARC will have released an updated version of the Interceptor that more than doubles the detection distance.

We then took our testing to a different, more common, arrangement. You've probably encountered one like it: you come around a corner or over a rise, and there they are, no warning, just several hundred feet down the road. In testing the Interceptor in this setup, it did much better, handling the close-range instant-on radar in stride and with complete immunity. Neither gun ever got a reading on the Ferrari!

What about those of us who use a truck to trailer our Ferraris to FCA events? Since trucks have a considerably larger frontal area than any Ferrari, I also wanted to know if the Interceptor could still offer them protection against radar. The bottom line: yes! Tests with a Chevy Blazer as the target vehicle showed that the Interceptor offers almost as much protection there as it does for a wedge-shaped sports car.

The Mirage 2001 provides some protection against radar and is a reasonable adjunct to a radar detector for the budget-minded; when Phantom comes out with their active jamming unit, which is based on an advancement of the Stealth VRCD, it will certainly be worth a look. For now, though, the Interceptor, while not perfect, is probably the best there is at this point in today's market of stealth technology. In addition to the 1-year parts and labor warrantee against malfunction, a 3-year extended warrantee is available for an additional $47. In coming development, they expect to be able to offer a Ka-band upgrade and a rear-facing jammer will soon be available for the truly paranoid. We plan on testing the competitors' products, and the Interceptor upgrades, if and when available. But, most of all, remember that such gadgets will never, never take the place of safe driving.

Radar Countermeasures - An Update (January 1996)
In June (1995) we reviewed and road tested radar jammers, concluding that passive jammers were underpowered by design and unreliable protection, and that the only active jammer in mass production at the time, the ARC Interceptor, while it had its limitations, offered a fair amount of protection. For our update, we contacted the three companies which already had or had been working on active jammers and asked for their latest. Rocky Mountain Radar still hadn't released their unit, and weren't even to the point of providing us a prototype. Phantom Technology/Jammers Inc. (800) 451-4477 had just released their Phantom RCD (Radar Cloaking Device) and provided us a unit to test. ARC (Advanced Radar Components, 800-949-7539) sent us two of their latest release of the Interceptor.

We tested in two modes: along a straight stretch where the radar guns stay on and the car starts well out of range and drives toward the radar gun, and a second scenario where the car comes around a curve and the radar gun is used in instant-on ("pulse radar") mode. Our radar guns were again provided by Radar Sales (612-557-6654), who have a wide variety of new and refurbished radar guns for sale to the public. We used two MPH-Industries K-15 police model stand-by-the-patrol-car-and-point radar guns, one in X-band and one in K-band.

Before we got to the road test, we compared features of the two competitors. The Interceptor is 5.2"x3.2"x2.2" roughly comparable in size to the Phantom RCD's 6.125"x4"x1.75". Both are considerably larger than typical radar detectors, since they must house the transmission oscillators and horns, while detectors simply need antennae surface and board electronics. The Interceptor is a digital design, and has flush-mounted front panel switches and indicators in its molded case which include a power switch/on-indicator, a dimmer switch for night operation, and X and K indicators with signal strength for the radar detector function. The unit has a self-test which flashes all indicators and beeps. It sports RDD/VG2 immunity for those states that use radar detector detectors. With the unit comes a simple but adequate manual, both windshield and visor mounts, and coiled and straight power cords, including an extra fuse. The Interceptor has a 1-year warrantee, and sells for $595. In contrast, the Phantom is an analog design, and is an adaptation of David Sullivan's well-known and well-regarded Stealth VRCD, which is no longer in production. The new Phantom RCD is in a metal and plastic case and has front panel push-button on/off and test buttons, recessed scan/power and alert lights, and a side-mounted thumbwheel volume control. With Jammer Inc.'s permission, we opened the case, as we had done previously with the Interceptor. Although the fully assembled unit looks as if it were built in a basement/garage shop, the internal assembly quality appears good, and the circuit boards have only a couple of what appear to be hand-soldered patch components. For accessories, the Phantom RCD comes with only a visor mount and a straight-only power cord. The Phantom RCD manual, though, is excellent, and covers not only the basic operation of the unit, but also well-written sections on how the jammer works against radar, driving techniques, jammer limitations, and legal issues. The Phantom RCD has a 90-day warrantee, and sells for $545.

Performance on the road, of course, is where it all counts. With the help of fellow FCA member and radar engineer, Victor Englert, we set up our testing on a controlled private road. Our test day's weather was clear and crisp (uh, cold). On our straight stretch, the X-band gun was able to get a reading from a distance of 1/4 mile, and the K-band able to read a little farther at 1/3 mile. Note that this is on the light side; as most radar guns are able to detect at a half-mile or more.

We tested the Interceptor first. As before, it was able to defeat the X-band with no problem. On the straight runs, the Interceptor detected the radar gun long before the car would have been in range of the K-15 radar gun. While on previous tests the Interceptor never allowed the radar gun to get a reading until the car was just about passing it, in this testing the gun acquired the car at approximately 400 feet, still providing 10-11 seconds of early blanking out of 15 seconds of total exposure at 60 mph, plenty of time to adjust your speed safely if appropriate, especially considering that the Interceptor warned the driver and started jamming at almost 3/4 mile away from the radar installation, well behind the gun's range. The Interceptor didn't fare as well against K-band, however. In our May/June 1995 test, we had one unit that did not cloak K-band and one that did, the former presumably chalked up to miscalibration. The new Interceptor unit we tested provided only intermittent cloaking for a total of about 4 seconds out of the 18 seconds of exposure at 60 mph, and they weren't all at the beginning of the gun's range limit. Since ARC had provided us two units, we swapped them out, and after suitable warm-up ran the other unit with virtually identical results: great on X-band, poor on K-band. In our close range instant-on testing, the Interceptor again cloaked the car against X-band so the gun got no reading until the car was around 250 feet away, but had no effect on the K-band gun.

We then hooked up the Phantom and let it run the gauntlet. Against X-band, it was only slightly less effective than the Interceptor, averaging 9-10 seconds of protection at 60 mph out of 14 seconds of exposure, all at the beginning of the exposure area, since it detected the radar gun and started jamming at around 3/5 mile, well beyond the gun's range. Against K-band, it beat the Interceptor significantly. The characteristics of the test on each of multiple runs were blanking for the first 10 seconds (approx. 900 ft) of exposure, then 1 second of reading, then 2-3 seconds of blanking again until the car was within 400 feet of the radar gun. This 1-second "blind spot" was not evident in the X-band test, but consistently showed up against K-band. In our close range instant-on test, the Phantom RCD provided cloaking in both X-band and K-band up to within 300 feet of the K-15 radar gun.

Since the K-15s had such low range, we acquired some higher-powered guns against which to test the Interceptor and Phantom RCD. On another clear crisp day, we put them against a CMI Magnum Speedgun (X-band), a Kustom Electronics HR-12 (K-band) and dashboard model HAWK (K-band). With jammers disconnected, the two handheld guns were able to get a reading on our test car at a more realistic 3/4 mile range, and the higher powered HAWK at 7/8 mile.

After we had advised ARC of our tests against the K-15s, they sent us another unit with some new pre-release software expected to improve K-band performance. For the first test, though, we started with the production/shipping version, and just as before, it had excellent, full-range masking against X-band. It still had only about 5-seconds of spotty masking against the two K-band units, which with the longer range, out of a 45- to 55-second exposure at 60 mph, is only 10% protection. With the new test unit, other than a half-second reading early in the run, it provided full masking against the K-band HR-12 until the car was within 50 feet of the gun, but only provided about 5 seconds of sporadic masking against the K-band HAWK. Characteristic of the no-masking periods of all the ARC units was that the Interceptor no longer beeped at the driver telling them that they are under surveillance, which makes us wonder if the real problem is in the detector circuitry/software.

Now it was the Phantom RCDs turn. Could it do as well against the higher-powered, longer range guns as it did against the K-15s? In short, an emphatic yes. Against the Magnum, it provided full masking to 400 feet of the gun. Against the HR-12, it provided full masking to 50 feet. Against the high-powered HAWK, out of 53 seconds of total exposure, there was masking for a clear majority of the run, with only about 4 seconds total of sporadic exposure where the HAWK was able to get a speed reading, until the car was 200 feet from the gun. In all cases, the Phantoms detector came on and provided the driver warning beyond the radar guns' range.

How do we interpret these results? First, the Interceptor. We know it works great on X-band. In fact, in separate controlled testing, we ran an Interceptor-equipped car against a K-15 X-band radar gun both straight run and instant-on at over 100 mph with no reading until the car was almost on top of the radar gun. We know that the Interceptor works against K-band - sometimes. But is this realm, "sometimes" isn't good enough. ARC told us that the problem was very likely related to the power drop when hooking the unit up through the cigarette lighter, and recommends the units be hardwired in to get 13.5 volts, though their documentation says 11.0 volts is the minimum necessary. Although we haven't had a chance to retest, we did do a voltage check on our test cars, and the lighter plug voltage was just over 13 volts with the engine running. In any case, we still have to contend that the units should be designed for "plug-and-play peace of mind."

The Phantom RCD is the clear winner, and we were quite pleased with it in these tests. While it doesn't have the features of the Interceptor, nor have we had the opportunity to examine multiple units as we have the Interceptor, the performance was certainly excellent for the Phantom RCD unit we tested. It provided more than adequate protection against X- and K-band radar for virtually any road or highway situation. While digital technology would normally be expected to beat out an analog design, the Phantom RCD's, mature technology licensed from David Sullivans Stealth VRCD design, wins over the digital Interceptor. We would like to see a longer warrantee period on the Phantom RCD comparable with ARC's, and perhaps additional front panel features and a windshield mount, but these are minor issues compared to the great road performance.

Both Phantom/Jammers Inc. and ARC have agreed to supply us additional units for further tests, including new updates as they are released. We hope to be able to compare the active jammer from Rocky Mountain Radar as well whenever it reaches production.

Remember that both the Phantom RCD and the Interceptor warn and protect against X-band and K-band only, and not against Ka-wideband, laser, vascar, photo radar or other means of speed detection. But again, most of all, remember that such gadgets will never, never take the place of safe driving.

March 1996 Update
Now that it's bee a couple of months since I did the test, I have to say it's a bit of a toss-up as to which unit to buy. As far as ARC goes, I believe that they have solved their problems on the Interceptor. As far as Jammers Inc goes, my original Phantom unit has now developed an extreme sensitivity to vibration so it goes off every time you hit any tiny bump in the road, and I haven't received the replacement I requested several weeks ago.

My natural tendency is to favor the digital design, but the test data I have so far leans the other way. I'm looking forward to testing again in a couple of months, since both suppliers expect to have tweaked their design some. If you want some additional info and talk with technical folks, here's my contacts, and do tell them I sent you. At Phantom, call Linda Robertson or Mike McKown at 307-358-1000; at ARC, call Dave Johnson at 919-489-1390. You'll get much better detailed info from these folks than you would calling their sales people. Again, please do mention my name and these articles.

Contributions to this FAQ by: Michael Charness