The most recent copy of this document can be found at: http://crash.ihug.co.nz/~geoff/radarfaq.htm Back by popular demand .. the radar FAQ! As before, any experiences with any brand of detector or jammer received with interest (anon OK if you are doing something naughty). I am especially interested in performance against photo radar and laser. Does anyone get the BMW or Automobile mags with all the tests? Geoff KotRFAQ If anyone has them or any other info, could they Email, snail mail or fax them to me. Note the change in e-mail address from the previous version! Fax 0064-9-2360639 ph 0064-9-2948552 snail mail: Hauroko Farm Flays Road RD 3 Drury South Auckland New Zealand E-Mail:: Geoff@ihug.co.nz Any comments or improvements, please let me know. - Geoffrey Merryweather Radar detector FAQ. v1.1 Thanks to all the people who replied and freely gave their opinions of radar countermeasures. Any errors are probably mine, and the spelling mistakes certainly are. I have taken out the section with the radar detector reviews, as many of them were getting out of date and accurate, up to date information is hard to find. I can put it (or something similar) back in if there is popular demand. In this case, probably all I can do is summarise some of the tests which have been published recently. One problem with living in New Zealand is that we don't get all the magazines, so I am missing some of the articles. RADAR - KNOW YOUR ENEMY Almost all the world's police forces use radar for measuring speed, enforcing speeding limits and collecting revenue. Ever since it was invented, anti radar measures have followed close behind. Unfortunately, the police operate with 2 aces - they can pick the time and location to make the most of the hunter's advantage of surprise ( and increase the kill ratio by choosing places most people speed, whether or not it is dangerous) and the most effective active countermeasures such as jamming and anti radar missiles are illegal. Radar works by sending out pulse or a continuous signal of radio waves and listening for the reflection. When the pulse hits a moving object, it's frequency changes, the exact amount of change depends on the speed of the object and the direction it is travelling in. There is also a new system out that uses laser light to measure speed. There are 3 main frequency areas that police radar works in, generically known as X band (11 GHz), K band (24GHz) and Ka band (32- 36GHz). All a radar detector does is listen to those frequencies and beep, chirp and flash when it receives a signal. The more sensitive it is, the earlier it will warn you. Unfortunately, the 3 frequency bands are also shared by garage door openers, burglar alarms and natural radiation from power lines. This raises the second part of the equation - a radar detector that falses more than it warns is useless. Unfortunately, the two parts are incompatible to a large extent and this is the major difference between the el cheapo special and the top of the range model, apart from the number of LED's that they come equipped with. LIDAR - THE NEW ENEMY LIDAR is different from conventional radar in that it uses laser light (frequency around 900nm) to detect the vehicle speed and measures the distance from the gun to the target several times. From the change in distance, it can calculate the speed. As it measures distance, it is important that the gun is held very steady to get an accurate reading, and the usual target in this case is the number plate which is easy to see and a good reflector. This is important because the gun relies on the reflections from the target to calculate the speed. From the drivers point of view, what makes it different from radar is that it is very hard to detect. The beam width is only around 4 feet wide at half a mile and there is very little scatter for the detector to pick up. All Lidar guns are also "instant on" where it locks on (almost) instantly on the target when the trigger is pulled and is not left running constantly like some radar guns. Photo radar - an easy way to raise some funds The latest twist on the speed detection is photo radar, where you don't know you have been clocked until you get a tax invoice in the mail. These have either a low powered radar unit or detection loops (like those used on traffic lights) to detect the vehicles speed and it then takes a photo of the car and the registered owner gets the bill, and either has to pay or say who was driving at the time. Innocence until guilt is proven is not a major issue with these units, as the machine cannot lie :-) The radar guided units have the radar angled across the road so that it is harder to detect and reduces the chance of multiple echoes and false readings. The radar is very low powered as the target is usually only 30 -50 metres away. Again this makes it very hard to pick up with a radar detector as you are relying on scatter from the radar beam off other vehicles or buildings. There are a number of different units around; Australia uses the Fairy slant radar system which has a K band radar at 45 degrees across the road. They also use other units but I have no information on them. New Zealand uses the Auto patrol Ka photo radar unit and it is deadly. It uses a low power 34.6ghz unit angled at 22.5 degrees across the road and can take photos of cars going in both directions. It doesn't take a photo if it detects multiple vehicles in order to save film. The frequency is deliberately chosen to be the third harmonic of the X band, an area where most radar detectors reduce their sensitivity to avoid false alarms from X band sources. My Valentine One doesn't detect this system at all for this reason. The other system operating in NZ is a fixed pole mounted camera. There are more poles than cameras and the police play the shell game moving the cameras between the poles to keep everyone guessing. These use underground detection loops to positively identify which car is being snapped, and there are no radar transmissions to pick up. There have been some cases of public spirited citizens painting over the lenses recently. Britain uses the Dutch Gatso fixed cameras similar to the above system. Vascar This is not a radar system, rather it is a glorified stopwatch that relies on the policeman's honesty (scary thought). They are mounted in the police car and are often used when following the target. When the target car goes past a landmark, the timer is started and when it goes past the second landmark, the timer is stopped. It is hooked up to the speedo to give a speed reading. It relies on the button being pushed at the right time and the pacing distance to be long enough to overcome any timing errors. The only countermeasure is careful observation. Countermeasures Radar jammers. Since the Gulf War, electronic countermeasures have become popular. As far as the civilian population is concerned, radar jamming has a number of serious disadvantages. Firstly, jammers seem very expensive for what you get, because 2/ they either don't work or they are illegal. The exact regulations vary from country to country. In the USA, it is covered by the FCC regs regarding interference of a radio transmitter (the radar gun) and it is also covered by a catch - all phrase "interfering with an officer in the course of his duties". This usually has a jail sentence attached to it - at least with a speeding ticket, you can still get out and walk. The other point is that the cop can still estimate your speed and probably make it stick. If you blow past him at 100 mph while his radar unit stays mute, he will be suspicious... Having got the legal stuff out of the way, what about the jammers you see advertised? Jammers usually come in 2 flavours, passive and active. The passive variety are those sold by Rocky Mountain Radar and others under the Spirit or Eclipse brands. These are supposed to get the incoming radar signal, scramble it up and retransmit back to the radar gun (without amplifying it further). The problem with this theory is that the antennae is about 1 inch square, which is minuscule compared with the frontal area of the car. Any signal sent out by the jammer would be drowned out by the reflections from the car and rejected by the noise cancelling software of the radar gun. A test published on the Net by John deArmond and a test in Car and Driver (not surprisingly) found that these only make your bank balance invisible and not your car invisible. Active jammers are the more interesting (and illegal ones). In this case, the unit sends out a strong signal to drown out the reflections from the car. The only unit for which I have seen independent test results is the VCDD Stealth, which sells for around $US700! The makers claim it is legal, but do you want to be a test case to find out? This works by combining a low quality radar detector with the transmitter, When it detects a signal, it transmits in that frequency range. Both Car and Driver and NZ Autonews did tests on and it works with some serious provisios: - It only works from the front. - It doesn't work well at short range - It only works on X and K band - It is very large and bulky - It sets off every other detector within miles Given these faults, the high price and the likelihood of it being illegal or made illegal, I don't think it can be justified. There is another jammer advertised on the net with some interesting claims. The URL is: http://www.shore.net/~adfx/2484a.html There is a review of this on: http://www.orst.edu/~varineb/jammer.htm. I have not had anything to do with this jammer and would like some more info if anyone gets one. Despite their claims for legality, I still have my concerns as listed above. Stealth There is little "Stealth" material available regarding cars, and the trick radar absorbing materials used on the USAF planes is not yet available at the local surplus store.... Car shape has the biggest effect. Driving a car like a Mazda RX7 with a low profile and fold down headlights and the motor at the back is a lot better than a minivan or semitrailer. There have been some car- bras advertised in past years which are supposed to lower radar profiles. I have not seen any formal tests on these, but the feedback I got was that they were ineffective for this. Lidar jamming Unlike radar, lidar is just light, and hence jamming is easier and (quasi) legal, or at least it is impossible to prove that was your intention. Car and Driver magazine (April 94) had a good article on this which concluded that a pair of high power spotlights can reduce the range the radar gun can pick you up by half, and may make that lidar detector vaguely useful as it gives you a couple of seconds more warning. Robert Weverka, who looks after the Lidar FAQ, and an article by Craig Peterson (Autotronics, March 95, p36) shows that this cannot work. This doesn't explain why C&D got their positive reults. In any case, driving lights are always a good thing to have, so it cannot do any harm Robert also has a test of a Lidar jammer on his web site (see the end of this FAQ for the URL) Lidar stealth Lidar works on reflection off the target by light, so the best means for stealth with Lidar is to have a low profile, filthy matt black car without a numberplate or chrome trim. Whether you would want to be driving a car like that anyway... There have been covers to go over number plates to reduce the reflection. I have seen no tests on these at present. RADAR DETECTORS A radar detector is essentially a radio receiver that whistles, beeps and chirps when it gets a signal on the same frequency as the radar band. Besides flashing lights, the main differences between the various models is sensitivity and false alarm rejection. The two are mutually exclusive to a large extent. General Opinions And Reviews The detector manufacturers are coming out with new models all the time, and it is hard to keep up with the changes. Price is not really an indication of quality, as the Uniden LRD2200 has had good results against Ka radar (NZ Autonews) yet it is the cheapest detector in the range. On the other hand, my $US400 Valentine One won't pick up the NZ photo radar operating on 34.6 Ghz - it is a case of over technology as this region often has reduced sensitivity to reduce false alarms. Valentine have said they can tune it to be more sensitive at this frequency for $US45, which I will get done in early 1996 and will report the results then. Recent tests include: Automobile December 1995, pages 67-74 Rankings: 1/ Bel 745Sti 2/ Uniden LRD 6399SW (budget model pick) 3/ Valentine One (tie) 3/ Escort Passport 4600 (tie) 4/ Whistler 1470 5/ Cobra RDL 712SW Automobile December 1994 1/ Bel 645Sti Car and Driver April 1994 1/ Valentine one (87 points) 2/ Bell 966ST (54 points) 3/ Escort Passport 3200 (53 points) 4/ Whistler 880 (46 points) 5/ Cobra RD 306 ( a re badged Passport) (39 points) NZ Autonews (sorry, don't have the issue here) Test was against Ka photo radar only 1/ Uniden LRD2200 The Uniden under-the-bonnet RD7000 model also did well in this test. This detector would be a good choice where you don't want to have the detector in plain view. The Bel 645 also did fairly well in this test, although the Australian Whistler detectors got slammed. WHAT TO LOOK FOR Apart from price, things to check are: sensitivity - the manufacturers sometimes publish lab test results. look for at least 110 dB Memory - Having to reset the settings everytime you start up is a pain, and this is one of the failings of the Valentine. Display - make sure you can see it in bright sunlight. This is a problem with weak LEDs or LCD displays Mute - so that cop cruising behind you with his radar on doesn't drive you crazy. Stealth - even if radar detectors are not illegal in your area, having a detector - detector proof detector (what a mouthful) means that you don't set off every other one on the road with false alarms. Adjustable volume - the Australian Whistlers don't have them and I wouldn't buy one because of it. Wideband - it should pick up the entire Ka band (all modern ones do) as well as K, X and lidar. Different lights and tones for each band - so you can tell what is worrying you. WHERE TO MOUNT IT Generally the best place to mount a detector is up high, by the rear vision mirror. This allows it to get the best view of the road and gives the maximum range. There is also another reason to put it up high. Lowlife thieves can't see it and break in and steal it (happened to me), and if you do get pulled over, there is less chance of a cop seeing it. If a cop sees a radar detector, forget any chance of talking your way out of the ticket. The only thing to watch is some cars have a metal film tint along the top of the windscreen and this can block the radar and lidar which reduces the effectiveness. MOTORCYCLE USE Motorcycles pose special problems for radar detectors. You need one with an earphone jack so you can hear it, and only Whistler and Escort make them as standard. Nady also had a motorcycle specific detector, but it doesn't have Ka band and isn't very sensitive. I had one of these and would not recommend it now. Vibration is also a problem for motorcycle use and little can be done about this. Mountings for motorcycles can either be the suction cup fittings onto the fairing blade or in the top of a tank bag. RADAR DETECTOR DETECTORS Some countries or states have banned the use of radar detectors, and the usual weapon against detectors is the Canadian VG2 detector detector. Most radar detectors work on the superhetrodyne principle where the incoming signal is mixed with that from an oscillator inside the detector to help eliminate noise and improve sampling sensitivity. Unfortunately, the oscillator also "leaks" and this is what the VG2 (and other detectors on the road that false alarm) pick up. Most detector makers have come out with a "stealth' model that the VG2 cannot pick up, with the best in this area seem to be the top Bels and the Valentine One. To raise the stakes even further, Whistler have now included a VG2 detector - detector - detector in some of their models which shuts down the unit when it detects the VG2 nearby. Don't forget also that the police can rely on the Mark 1 eyeball. If you are going to use a detector in a VG2 infested area, I would buy one of the under bonnet models such as the Uniden RD7000 series, so it cannot be seen, but make sure it is truely "stealthy". USEFUL SITES As this is the Internet, no article would be complete without some links to other sources: NMA home page (http://www.motorists.org) The NMA have some good information published here and also have books. Being a US organisation, it has a US bias (such as publishing a list of speed traps in the US), but is still worth a visit. Lidar FAQ If you want to know more than the brief overview I have given here, all the details are in the Lidar FAQ at http://www.speedtrap.com/speedtrap/faqonlid.html. A highly recommended site. ARC radar jammer home page I would be interested to hear more of this product - I have never used one: http://www.shore.net/~adfx/2484a.html Photo radar home pages: http://users.feldspar.com/~mtrenout/photo2.html http://www.inforamp.net/~dma/photorad.html