jkimble@bally.Bally.COM (The Programmer Guy) (08/01/90)
I saw a story on the world news a few weeks ago regarding drivers (primarily 18-wheelers) using radar detectors. During the news segment, the reporter was talking to a highway patrol officer who was using a device to detect if the oncomming vehicle was using a radar detector. I'm completely ignorant of internals of radar detectors, but I had always thought they were passive devices that didn't emit anything. Is this a wrong assumption? How do these detectors of radar detectors work? If radar detectors emit something, would that explain why I sometimes get a very low-powered K-band reading from on-comming cars that also have radar detectors? I have a Bell Vector-3 that seems to do a good job of limiting false signals (I can almost always visually associate a police car with a strong reading), but on long drives in the middle of nowhere I'll get a low-powered warning signal when there doesn't appear to be any police cars around for miles. I used to write this off to the radar waves straying from a distant cop, but it was too consistant: no police cars anywhere, the on-comming car had a radar detector sitting on his dash. Can any electronics wizards kindly enlighten me? Please e-mail or post, whichever you feel appropriate. Thanks much, -- --Jim Kimble, jkimble@bally.bally.com Consultant: Have kernel, will travel uunet!bally!jkimble "ALPO is 99 cents a can. That's over SEVEN dog dollars!!"
dt@yenta.alb.nm.us (David B. Thomas) (08/01/90)
jkimble@bally.Bally.COM (The Programmer Guy) writes: >I saw a story on the world news a few weeks ago regarding drivers >(primarily 18-wheelers) using radar detectors. During the news >segment, the reporter was talking to a highway patrol officer who was >using a device to detect if the oncomming vehicle was using a radar >detector. Radar detectors are superheterodyne receivers -- a long scary word for a very simple thing, as usual. Inside the radio, the incoming signal is mixed (heterodyned) with a locally-generated signal (the local oscillator), which differs from the incoming signal by a fixed amount (the difference is the Intermediate Frequency or IF). When signals are mixed, the sum and the difference automatically come into being. The sum is ignored and the difference (the IF) is amplified and dealt with as the received signal. Superhet receivers are better in many ways I won't go into here, but the advantages are so great that almost any radio receiver of any kind you can buy is a superhet. The upshot of all this is that the local oscillator does generate a signal close to the signal being received. This can set off other detectors, as you have observed, and can be picked up by anyone scanning for it. It is possible to shield the local oscillator so it will emit almost no radiation. Broadcast receivers used to interfere profusely with each other, too, until this type of shielding was required by the FCC. Soon, perhaps, radar detectors will follow suit. Until then, you are legally broadcasting the fact that you have a radar detector. David
commgrp@silver.ucs.indiana.edu (BACS Data Communications Group) (08/01/90)
to sci.electroics and rec.autos: jkimble@bally.Bally.COM (The Programmer Guy) writes: Subject: Detecting Radar Detectors >I saw a story on the world news a few weeks ago regarding drivers >(primarily 18-wheelers) using radar detectors. During the news >segment, the reporter was talking to a highway patrol officer who was >using a device to detect if the oncomming vehicle was using a radar >detector. >...How do these detectors of radar detectors work? ... A friend sent me an article from a Virginia newspaper, _Lessburg Today_, July 13, 1990, entitled "Radar 'Detector Detictor' Cruises Local Primary Roads." "...The $1100 device detects microwaves "leaking" from operating radar detectors... Originally developed in Canada, where radar detectors are illegal... The VX6-2 detector is being fornished at no cost on a loan basis to the state police by the Insurance Institute for Highway Safety, a private research organization funded by insurance companies..." There's a picture of the beast, which is housed in a box aprox. 3 x 4 x 6", with two knobs and a LED on the front. It looks home-brewed. --- This article seems to confirm rumors that the insurance cartel wants to outlaw radar detectors everywhere in the U.S., either through the legislators they own, or by excommunicating/sh*tlisting policyholders who use them. These devices have been used in Canada for several years. They are for real, and apparently very effective. Superhet radar detectors work like little spectrum-analyzers: The local oscillator (11.5 GHz +/-) is a Gunn diode with a varactor to sweep its frequency. The first i.f. is 1 GHz, followed by further conversion and circuits which detect valid alarm conditions. K-band is detected via a harmonic of the local oscillator; I haven't done the arithmetic. The advantage of this method is that it searches a wide band but retains high sensitivity. The local oscillator, varactor and mixer diodes are all inside a cavity at the end of the horn antenna. A series of screws projecting into the horn form a trap to suppress local oscillator radiation, but are only partially effective. Some brands of radar detector mutually interfere because of local-oscillator radiation. In WW II, the Germans installed radar detectors on U-boats. These also had a problem with local-oscillator radiation, and Allied ASW aircraft were able to home-in on them without radar. A detector-detector could probably be made by modifying a conventional radar detector: Mechanically retune its local oscillator to 1 GHz above or below 11.5 GHz, and remove the trap screws. -- Frank Reid W9MKV reid@ucs.indiana.edu 26 states on 10 GHz. ZAP! ;-)
hbg6@citek.mcdphx.mot.com (08/02/90)
In article <1695@yenta.alb.nm.us> dt@yenta.alb.nm.us (David B. Thomas) writes: > >It is possible to shield the local oscillator so it will emit almost no >radiation. Broadcast receivers used to interfere profusely with each other, Is it possible to install suitable shielding in a current model detector? John ..................................................................... All opinions expressed are mine and not Motorolas, their loss. .....................................................................
t-petesk@microsoft.UUCP (Peter SKELLY) (08/02/90)
The Detector Detectors could be picking up the Local Oscilator generated by the radar detector. This signal is mixed with the incoming radar signal, which has the effect of creating a signal that is the sum of the two signals, and a signal that is the difference of the two signals. This LO signal would have to be pretty close to the X or K band. From what I remember about taking apart some detectors, is that most of them are poorly shielded/filtered. This leavs a lot of room for the LO emmissions to get out. Pete Skelly KB7GUD my opinions are my own
wb8foz@mthvax.cs.miami.edu (David Lesher) (08/02/90)
It's not hard at all for the average cop to figure out you have one. 1) Sit there. 2) Blip instant_on radar unit. 3) Watch/listen for car that slams on brakes. Difficult, isn't it? -- A host is a host from coast to coast.....wb8foz@mthvax.cs.miami.edu & no one will talk to a host that's close............(305) 255-RTFM Unless the host (that isn't close)......................pob 570-335 is busy, hung or dead....................................33257-0335
bbesler@vela.acs.oakland.edu (Brent Besler) (08/02/90)
The insurance Gestapo wanting to ban radar detectors is nothing new. GEICO tried to refuse policies to people who use them and were ordered to reinstate the policies in two states, I don't remember which. THe radar detector detector picks up the 11.5 Ghz reference signal most detectors put out. MAYBE the new Solo, which is pretty low powered and uses a GaAs FET rather than a Gunn diode may not be detectable by it. Anybody on sci.electronics who would know the answer please share it with us.
wchan@umd5.umd.edu (Winthrop D Chan) (08/02/90)
In article <1695@yenta.alb.nm.us> dt@yenta.alb.nm.us (David B. Thomas) writes: >jkimble@bally.Bally.COM (The Programmer Guy) writes: > >>I saw a story on the world news a few weeks ago regarding drivers >>(primarily 18-wheelers) using radar detectors. During the news >>segment, the reporter was talking to a highway patrol officer who was >>using a device to detect if the oncomming vehicle was using a radar >>detector. It seems like that device has been in use for quite a while up in Canada. At least in Ontario, Canada. I was up there a few weeks ago with a friend and as soon as we crossed the Border at Buffalo, they snagged us and told us to put the detector away and it was illegal to use it in Ontario. Winthrop
fmgst@unix.cis.pitt.edu (Filip Gieszczykiewicz) (08/02/90)
<I saw a story on the world news a few weeks ago regarding drivers <(primarily 18-wheelers) using radar detectors. During the news <segment, the reporter was talking to a highway patrol officer who was <using a device to detect if the oncomming vehicle was using a radar <detector. <police car with a strong reading), but on long drives in the middle of <nowhere I'll get a low-powered warning signal when there doesn't appear <to be any police cars around for miles. I used to write this off to <the radar waves straying from a distant cop, but it was too <consistant: no police cars anywhere, the on-comming car had a radar <detector sitting on his dash. Greetings. That happened to me, on a trip from Pittsburgh to Virgina Beach. Except that I did NOT "write it off"... After a few miles, I saw a cop pull out from the BACK.... They are getting smarter. I was going 65 (the speed limit, well... :-) but one guy passed my going, minimum, 80MPH. Sure enough, the cop was in an unmarked car and overtook me and pulled the guy over. Another thing. My detector would beep ONCE every few seconds. To not give themeselves away, the cops use a radar "burst". By the way, there is a simple way they can check if you have a radar detector. They will get behind you and time you. If they see you hit the brakes, you're DEAD. (Some states require them to do that 2 times... or so I hear) Solution. If you have cruise control, and you are going say 75, and the cop is clocking you the FIRST time :-), hit the "set" on the cruise control. It will (should) drop your speed by about 2 MPH. You should do that a few times (practice it :-) and WHOLA! no brakes required! (I never said the above...) <--Jim Kimble, jkimble@bally.bally.com <Consultant: Have kernel, will travel uunet!bally!jkimble <"ALPO is 99 cents a can. That's over SEVEN dog dollars!!" Take care and drive safely. By the way, if you drink and drive, you will never remember what to press, so don't drink... as if you need another reason..... -- _______________________________________________________________________________ "The Force will be with you, always." It _is_ with me and has been for 10 years Filip Gieszczykiewicz "A man without a dream is like a fish without water." FMGST@PITTVMS or fmgst@unix.cis.pitt.edu "My ideas. ALL MINE!!"
commgrp@silver.ucs.indiana.edu (BACS Data Communications Group) (08/02/90)
bbesler@vela.acs.oakland.edu (Brent Besler) writes: >The insurance Gestapo wanting to ban radar detectors is nothing new. >... >The radar detector detector picks up the 11.5 Ghz reference signal >most detectors put out. MAYBE the new Solo, which is pretty low >powered and uses a GaAs FET rather than a Gunn diode may not be >detectable by it. Anybody on sci.electronics who would know the >answer please share it with us. The Gunn diode is a simple/inexpensive but inefficient (about 2%) way to produce microwaves. That's the main reason why most radar detectors require so much power that it is impractical to operate them from internal batteries. (Although the physics are different, you can think of a Gunn diode as a LED which emits microwaves instead of light, except that it must be inside a resonant cavity to do so, and the cavity determines the microwave frequency.) The new generation of radar detectors (e.g. Solo) with FET local oscillators require less DC power, however, the local oscillator RF level is probably the same as in older types, and probably has equivalent leakage. -- Frank Reid reid@ucs.indiana.edu "Aha! The alien Zorg battle cruiser's BMW disguise is flawed by a suspicious lump on the dash. Set nuclear nerd neutralizer to medium- well!"
cgordon@vpnet.chi.il.us (Gordon Hlavenka) (08/03/90)
>... How do these detectors of radar detectors work?
In order to get the best sensitivity out of a radio receiver (which is what
a radar detector is) a technique called heterodyning is used. An oscillator
is run at a frequency which differs from the desired receive frequency by
some known amount. The oscillator output is mixed with the antenna signal,
and several products are produced, one of them at the difference frequency.
Why is this done? Because then the rest of the amplification can be done at
the intermediate frequency, which will always be the same. (Tuning is
accomplished by changing the _oscillator_ frequency.) The narrow-band
amplification of the IF circuit (IF stands for Intrinsic Framis; the
circuit is named for its inventor, Framis McGillicudy, WAK01) is more
efficient.
However this Local Oscillator also radiates some of its energy. So if you
know the IF frequency of the receiver, and the selected receive frequency,
you can calculate the LO frequency and look for it.
The FCC has used this (rumor has it) to look for TV sets tuned to pay-tv
stations. Theoretically, their counts of how many receivers were tuned to
channel 44 (ON-TV in Chicago) could be compared with subscriber counts to
determine the level of pirating going on.
The military uses this technique to look for particular receivers on other
ships/aircraft/etc. By building an RF "signature" of the contact, it can be
pretty accurately identified.
Of course, the police are probably using heterodyne receivers to look for
radar detectors. So you could (conceivably) build a radar detector detector
detector. (And the cops would have to build a ...)
In Illinois, most police cars carry a Motorola receiver locked to the ISPERN
frequency. (A statewide emergency network.) I have toyed with the idea of
building an ISPERN detector; it would detect police _cars_, not the radar.
----------------------------------------------------------
Gordon S. Hlavenka cgordon@vpnet.chi.il.us
Disclaimer: Any resemblence between Framis McGillicudy and
a ficticious character is pure.downin@dtoa1.dt.navy.mil (Downin) (08/07/90)
On the subject of radar detectors, is there some relatively inexpensive and fairly easy way to build a radar gun jammer that could opperate through your stereo or cb antenna? Dave Downin
vail@tegra.COM (Johnathan Vail) (08/07/90)
In article <26b8be39-32e.2sci.electronics-1@vpnet.chi.il.us> cgordon@vpnet.chi.il.us (Gordon Hlavenka) writes: In Illinois, most police cars carry a Motorola receiver locked to the ISPERN frequency. (A statewide emergency network.) I have toyed with the idea of building an ISPERN detector; it would detect police _cars_, not the radar. ---------------------------------------------------------- Gordon S. Hlavenka cgordon@vpnet.chi.il.us Is this in anyway similar to the "CHiPs" detectors being sold? The description was vague, something about being able to detect the cars because of the mobile repeater in the car. The repeater is used to allow a respectable range out of the walkys. I infer that the detector works by either detecting the LO or by kerchuncking the mobile repeater. Since a cop described the use of the detector as being very illegal the kerchunking approach seems more likely. Of course, under the evil ECPA of '86 maybe the LOs of police radios are illegal to recieve... Anybody know anything real? "The crux of the biscuit, is the apostrophe" -- This is the dog talking... _____ | | Johnathan Vail | n1dxg@tegra.com |Tegra| (508) 663-7435 | N1DXG@448.625-(WorldNet) ----- jv@n1dxg.ampr.org {...sun!sunne ..uunet}!tegra!vail
brian@ucsd.Edu (Brian Kantor) (08/07/90)
In article <2860@nems.dt.navy.mil> downin@dtoa1.dt.navy.mil (Dave Downin) writes: >On the subject of radar detectors, is there some relatively inexpensive >and fairly easy way to build a radar gun jammer that could opperate >through your stereo or cb antenna? No. If you want to use your CB whip to beat le flic senseless, that'd work. I assume you aren't interested in methods involving direct physical assault. But if you want electronic methods, no, radar jammers of the kind that would simply prevent speeding from being detected are sophisticated enough that you probably couldn't build it, and it wouldn't use your stereo or CB whip anyway - you'd need a horn or dish pointed at the cop's radar gun, and that's not likely to be inconspicuous. The big rotating propeller on the front of the car doesn't work either, despite popular myth. If you want to avoid getting tagged by radar, drive a mostly plastic car with the radiator and firewall slanted downward. That reduces the radar aperture of your vehicle (i.e., how well it shows up on radar) and makes it likely the cop will get a reading off someone else. If you're alone on the road, you're nicked, cobber. Flames about driving faster than someone else's concept of the rate of progression at which you magically turn from safe driver to homicidal maniac will be noted, logged, and ignored. - Brian
tuv@pmafire.UUCP (Mark Tovey) (08/07/90)
In article <2860@nems.dt.navy.mil> downin@dtoa1.dt.navy.mil (Dave Downin) writes: >On the subject of radar detectors, is there some relatively inexpensive >and fairly easy way to build a radar gun jammer that could opperate >through your stereo or cb antenna? > >Dave Downin I have seen plans for building such a thing, however it can't work through the stereo or CB. It requires a fairly expensive microwave diode and a small horn for transmission. It was designed to be used in conjunction with a detector. If the detector was triggered by a rader transmission, it would trigger the jammer automatically. One other thing, I believe that such a device is illegal. You wouldn't be able to hide it very effectively either. As soon as the police officer's rader unit went wild, he would know that he had been zapped and would start looking for the culprit.
chrispi@microsoft.UUCP (Chris Pirih) (08/08/90)
In rec/autos "commgrp@silver.ucs.indiana.edu" might have said: ;Subject: Detecting Radar Detectors ; ;These devices have been used in Canada for several years. They are ;for real, and apparently very effective. I guess what we need now is a radar detector detector detector. (Or did you already say that?) --- chris
alex.szkabarnicki@f910.n250.z1.fidonet.org (alex szkabarnicki) (08/10/90)
vv said => Of course, under the evil ECPA of '86 maybe the LOs vv said => of police radios are vv said => illegal to recieve... vv said => Anybody know anything real? Well I (thought) a radar detector IS a radio receiver. Since it is a radio receiver, why should there be a restriction on a receiver? Is this not an infringement on our FREEDOM OF SPEECH. I used to sell them and collect the sales tax on them and send it in. Then they ban them, at least they (gov't) should have returned the sales tax back to the purchasers. Transmitters need a license, since the radar is a transmitter, are they licensed? Alex Szkabarnicki COUNTRY BOARD - Bradford - Newmarket --- * Origin: (1:250/910)
jessea@dynasys.UUCP (Jesse W. Asher) (08/12/90)
In article <1990Aug07.150400.3929@pmafire.UUCP>, tuv@pmafire.UUCP (Mark Tovey) wrote the following: >In article <2860@nems.dt.navy.mil> downin@dtoa1.dt.navy.mil (Dave Downin) writes: >>On the subject of radar detectors, is there some relatively inexpensive >>and fairly easy way to build a radar gun jammer that could opperate >>through your stereo or cb antenna? > > I have seen plans for building such a thing, however it can't work >through the stereo or CB. It requires a fairly expensive microwave diode >and a small horn for transmission. It was designed to be used in >conjunction with a detector. If the detector was triggered by a rader >transmission, it would trigger the jammer automatically. This is called AECM - Active Electronic Counter Measures -in military terms. > One other thing, I believe that such a device is illegal. You >wouldn't be able to hide it very effectively either. As soon as the police >officer's rader unit went wild, he would know that he had been zapped and >would start looking for the culprit. It is indeed illegal. You must have a license from the FCC in order to transmit and you are not going to get one. I have thought of building one, myself, but I've considered it a waste of time since they would eventually catch you. I don't think the officers would realize what was happening the first couple of times. But the word would get out and they would set a trap of some sort to catch that dastardly soul that would pull such a hideous crime. One other note here. The way radars work is that waves are bounced off of cars and the frequency is changed depending on how fast the car is going. The radar measures the shift and approxiamates how fast the car was going according to how much of a shift occurred. Conceivably, you could build a AECM unit that would detect the incoming frequency and broadcast back some other frequency to fool the detector. Of course, you would still have the bounced frequency mixed in, so I'm not sure how well it would work.
cgordon@vpnet.chi.il.us (Gordon Hlavenka) (08/13/90)
>One other note here. The way radars work is that waves are bounced off of >cars and the frequency is changed depending on how fast the car is going. >The radar measures the shift and approxiamates how fast the car was going >according to how much of a shift occurred. Conceivably, you could build >a AECM unit that would detect the incoming frequency and broadcast back >some other frequency to fool the detector. Of course, you would still have >the bounced frequency mixed in, so I'm not sure how well it would work. This is called a "gate stealer." A- The military is already using it. B- Civilian versions have been advertised as well. The civilian versions which I saw advertised (a couple years ago, no I don't have the address) called themselves "calibrators" for radar repair shop use, and the largest print in the ad was the warning that this equipment "will interfere with police radar units, causing erroneous low readings." If the output power of the gate stealer is sufficient, the actual return will be completely masked. By calibrating to your vehicle's speed, it is possible to set the unit to produce any desired reading on the radar gun. The problem with this is that most cops can "eyeball" your speed within 5 mph anyway, and if the gun doesn't agree they'll probably pull you over for something else. (There's _always_ something!) ---------------------------------------------------------- Gordon S. Hlavenka cgordon@vpnet.chi.il.us Disclaimer: He's lying
richard@pegasus.com (Richard Foulk) (08/14/90)
>> I have seen plans for building such a thing, however it can't work >>through the stereo or CB. It requires a fairly expensive microwave diode >>and a small horn for transmission. It was designed to be used in >>conjunction with a detector. If the detector was triggered by a rader >>transmission, it would trigger the jammer automatically. > >This is called AECM - Active Electronic Counter Measures -in military terms. > I suspect an APCM would be more effective. And just as practical. (Anti Police Car Missile.) -- Richard Foulk richard@pegasus.com
henry@zoo.toronto.edu (Henry Spencer) (08/14/90)
In article <26c63bee-32e.10sci.electronics-1@vpnet.chi.il.us> cgordon@vpnet.chi.il.us (Gordon Hlavenka) writes: >The problem with this is that most cops can "eyeball" your speed within 5 >mph anyway, and if the gun doesn't agree they'll probably pull you over for >something else. (There's _always_ something!) And as a practical note, if you get caught interfering with police radar, you are in deep doo-doo -- probably criminal charges ("interfering with a police officer in the course of his duties"), not just a speeding ticket. -- It is not possible to both understand | Henry Spencer at U of Toronto Zoology and appreciate Intel CPUs. -D.Wolfskill| henry@zoo.toronto.edu utzoo!henry
svoboda@motcid.UUCP (David Svoboda) (08/14/90)
From article <26c63bee-32e.10sci.electronics-1@vpnet.chi.il.us>, by cgordon@vpnet.chi.il.us (Gordon Hlavenka): > > If the output power of the gate stealer is sufficient, the actual return > will be completely masked. By calibrating to your vehicle's speed, it is > possible to set the unit to produce any desired reading on the radar gun. I'm probably WAY out of my league here, as I've never worked with doppler radar before, but... As I understand, doppler radar sends a frequency which is reflected from the target which is moving towards or away from the gun. The gun receives the doppler shifted reflection amplifies it, and mixes it with the original transmitted frequency to obtain a beat frequency which is proportional to the relative speed of the target. Now, it seems possible that if you fed the receiver the appropriate BEAT frequency at a high enough level, then the amplification and mixing process would produce predominantly the beat frequency that you fed it, thereby giving a false reading, with no need of vehicle speed calibration. I seem to remember a construction article in Radio Electronics several years ago on a "Personal Auto-triggering Radar Calibrator", which did just this, and even sensed the current being drawn through your radar detector to automatically trigger. Of course, who would want to have to actually turn it on MANUALLY to calibrate their home radar units? :-) :-) Dave Svoboda, Motorola CID, RTSG, Arlington Heights, IL uucp => {uunet|mcdchg|gatech|att}!motcid!svoboda internet => motcid!svoboda@chg.mcd.mot.com A little boggling is good for the mind.
vekurpan@tekred.CNA.TEK.COM (Vincent E Kurpan) (08/15/90)
QUESTION: Why would anyone intelligent enough to build a radar jammer want to risk several felony charges and at least one federal offense to get out of a $35 traffic ticket. Anyone with the skills to build this has a high probability of seeking work with defense companies and if convicted of a felony you would not be able to get the security clearance. Also you could be interfering with aircraft or other military services (wouldn't that go over big ?). In short you could very easily end up in Leavenworth. It's fun to talk about but I hope no one is foolish enough to actually try it. I usually just try to go the posted speed limit. Just my philosophy :)
daveb@eng.umd.edu (David Bengtson) (08/15/90)
Basically, building a radar jammer is not all that complicated. I realize that RF/Microwave stuff seems like black magic sometimes, but it's really not all that complicated. As previously mentioned, Radio electronics has published several articals about jammers over the year, generally in the guise of a radar calibrator, with kits available, for educational purposes only. Besides, speeding tickets have gone up a bit, my father in law got one about 4 months age to 75 in a 55 zone, and the fine was $140 Dave Bengtson No longer a student !!!!!
vail@tegra.COM (Johnathan Vail) (08/15/90)
In article <26c63bee-32e.10sci.electronics-1@vpnet.chi.il.us> cgordon@vpnet.chi.il.us (Gordon Hlavenka) writes: >One other note here. The way radars work is that waves are bounced off of >cars and the frequency is changed depending on how fast the car is going. >The radar measures the shift and approxiamates how fast the car was going >according to how much of a shift occurred. Conceivably, you could build >a AECM unit that would detect the incoming frequency and broadcast back >some other frequency to fool the detector. Of course, you would still have >the bounced frequency mixed in, so I'm not sure how well it would work. This is called a "gate stealer." A- The military is already using it. B- Civilian versions have been advertised as well. The civilian versions which I saw advertised (a couple years ago, no I don't have the address) called themselves "calibrators" for radar repair shop use, and the largest print in the ad was the warning that this equipment "will interfere with police radar units, causing erroneous low readings." I think that this kind of device works by transmitting CW (continious wave) pulses at a certain rate to spoof the counters that actually measure the speed in the radar unit. Although I understand that this works to some extent, it should be easy to design around it and I have heard that some of the newer units will detect when they are being jammed. And even if they work for some cases, they will be farther off against moving radar. The first first poster is talking about sending back a shifted signal. This could work but is quite a bit harder to do. Since the IF of some units is in the middle of the 2M ham band, it might be possible to spoof the detector at this frequency. Anyway, given the extreme naughtiness of jammers and the very small advantage of them I believe the best defence is awareness and a good detector. Still, it's fun to speculate about. "Do policemen dream? ..Yes when they're fast asleep. And when policemen dream? ..It proves they're fast asleep" -- Robyn Hitchcock _____ | | Johnathan Vail | n1dxg@tegra.com |Tegra| (508) 663-7435 | N1DXG@448.625-(WorldNet) ----- jv@n1dxg.ampr.org {...sun!sunne ..uunet}!tegra!vail
vas@cbnewsi.att.com (vassilios.d.vassiliadis) (08/15/90)
In article <6141@tekred.CNA.TEK.COM> vekurpan@tekred.CNA.TEK.COM (Vincent E Kurpan) writes: >QUESTION: > >Why would anyone intelligent enough to build a radar jammer want >to risk several felony charges and at least one federal offense to >get out of a $35 traffic ticket. Anyone with the skills to build ^^^^^^^^^^^^^^^^^^!!!!!! >this has a high probability of seeking work with defense companies >and if convicted of a felony you would not be able to get the >.... [more stuff about military jobs and driving within the limit deleted] Well, I don't know about IL or wherever you are from, but out here in NJ a speeding ticket will cost you at least double the price you quoted, plus a surcharge of $150 (at least) in insurance and DMV fees for the next 3 years -if you're caught speeding 15MPH or more above the speed limit (any doubt that most speeding tickets are given to people driving faster than that? ) I'm not saying that I'd advise someone to build a radar-jammer, but you can't say that there is no real reason for someone -maybe someone already caught a few times...- to toy with the idea. Especially when so many roads have speed limits so low that a cyclist could get caught speeding :-)) obviously for no other reason but to get some poor souls to help the policeman to fill his quota for the day/week/month/year.... Vas (caught doing 40 on a 25MPH limit road, where you could easily AND SAFELY do 55!!! -and many people do, anyway! ) .-----------------------------------------------------------------. | Vassilios D. Vassiliadis | ^ ^ | They say: "Money Talks", | | att!homxa!vas4 | o | o | but all mine says is: | | AT&T Bell Labs, | _^_ | "GOODBYE!!!" | | New Jersey, USA | /===\ |*******************VAS*****| |-----------------------------------------------------------------| | Everything you read is my terminal's opinion; it has | | nothing to do with me or my company :-|..................... | `-----------------------------------------------------------------'
depolo@eniac.seas.upenn.edu (Jeff DePolo) (08/16/90)
In article <229@dynasys.UUCP> jessea@dynasys.UUCP () writes: >This is called AECM - Active Electronic Counter Measures -in military terms. >It is indeed illegal. You must have a license from the FCC in order to >transmit and you are not going to get one. I have thought of building one, >myself, but I've considered it a waste of time since they would eventually >catch you. I don't think the officers would realize what was happening >the first couple of times. But the word would get out and they would set >a trap of some sort to catch that dastardly soul that would pull such a >hideous crime. >One other note here. The way radars work is that waves are bounced off of >cars and the frequency is changed depending on how fast the car is going. >The radar measures the shift and approxiamates how fast the car was going >according to how much of a shift occurred. Conceivably, you could build >a AECM unit that would detect the incoming frequency and broadcast back >some other frequency to fool the detector. Of course, you would still have >the bounced frequency mixed in, so I'm not sure how well it would work. The way I see it, you would have to 1. Receive and count the incoming signal 2. Subtract the shift in the received signal caused by your velocity 3. Subtract the #2 shift again to compensate for the shift when transmitting your new signal 4. Add the approprite shift to correspond to 55 MPH 5. Retransmit at this new frqeuency That would be the most effective way. However, it would cost way too much and require quite a bit of hardware. The easy way is to take a CW carrier on approximately the same frequency as the radar gun is transmitting on and AM it at a frequency corresponding to the frequency you want the radar gun to hear. This AMed carrier, when mixed in the radar gun, will yield an AF signal which the radar gun will interpret as a Doppler shift. This should work on the "true" Doppler radar guns that use AF frequency counters to determine speed, but probably would not work on PLL radar guns, which are quite plentiful because they cost less. Anyone else have any ideas on this? --- Jeff -- -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- Jeff DePolo N3HBZ Twisted Pair: (215) 386-7199 depolo@eniac.seas.upenn.edu RF: 146.685- 442.70+ 144.455s (Philadelphia)
ins_atge@jhunix.HCF.JHU.EDU (Thomas G Edwards) (08/16/90)
In article <90081322451269@masnet.uucp> alex.szkabarnicki@f910.n250.z1.fidonet.org (alex szkabarnicki) writes: >vv said => Of course, under the evil ECPA of '86 maybe the LOs >vv said => of police radios are >vv said => illegal to recieve... >vv said => Anybody know anything real? > Well I (thought) a radar detector IS a radio receiver. Since it is a radio >receiver, why should there be a restriction on a receiver? Is this not an >infringement on our FREEDOM OF SPEECH. I think there should not be, but many others do, but it isn't an infringement on FREEDOM OF SPEECH, but it is more a matter of Right of Privacy, a less well specified right which many people believe they have (I think we should, be it in the Constitution or not). The question is that does the government have the right to make a law which can only be enforced by comming into your house and checking up on your receievers when just listening typically does not effect anyone. Also, how can the government limit measurement of RF energy which you are being exposed to? This must be balanced with the need for private communications (a serious economic issue). Personally, I think the ECPA is not good, and that those who use the "public" airwaves must encrypt confidential communications. However, are Police breaking the ECPA law by listening for Radar Detector Local Oscillators??????????? (Or do law-enforcement types not need to follow it?) -Tom
bbesler@vela.acs.oakland.edu (Brent Besler) (08/16/90)
Radar Detectors are legal in most places and if a cop catches you with the worst that will happen is a ticket for the full violation. Hidden small(Solo for example) or remote detectors may help that problem also.
chris@xrtll.uucp (Chris Baisly) (08/16/90)
In article <6141@tekred.CNA.TEK.COM> vekurpan@tekred.CNA.TEK.COM (Vincent E Kurpan) writes: >QUESTION: > >Why would anyone intelligent enough to build a radar jammer want >to risk several felony charges and at least one federal offense to >get out of a $35 traffic ticket. Anyone with the skills to build Well, because, at least in Canada, a $35 speeding ticket is more like $200. And that is only the start, because you will get a 'line' (a printed report) on your driving record, which will without a doubt raise your insurance rates. The fine itself is fairly inconsequential, it's the other ramifications.
v118hj3d@ubvmsd.cc.buffalo.edu (Anthony M Petro) (08/16/90)
In article <ADAM.90Aug16094229@chaos.cs.brandeis.edu>, adam@chaos.cs.brandeis.edu (The invertebrate punster, so slug me.) writes... >In article <26c63bee-32e.10sci.electronics-1@vpnet.chi.il.us> cgordon@vpnet.chi.il.us (Gordon Hlavenka) writes: > > >One other note here. The way radars work is that waves are bounced off of > >cars and the frequency is changed depending on how fast the car is going. > >The radar measures the shift and approxiamates how fast the car was going > >according to how much of a shift occurred. Conceivably, you could build > >a AECM unit that would detect the incoming frequency and broadcast back > >some other frequency to fool the detector. Of course, you would still have > >the bounced frequency mixed in, so I'm not sure how well it would work. > >The police are "road testing" a new type of speed reader. They are >visible light based. > >Driver's Drawbacks To Date. > o Impossible to detect electronically. > o Dificult to spot. > o Imopssilbe to jam. > >Police Drawbacks To Date. > o Matte Black cars don't show up. > >Question on radar. Has anyone designed the stealth buick yet? >adam@chaos.cs.brandeis.edu on the light-based thread: rumor has it that NYS troopers have been using a laser-based system with some high-performance sport-type car (not the usual heavy souped-up cop sedan) to snag folks on the NYS Thruway. traditionally, though, everyone on that road drives like a bat out of hell. of course, if this it true, it would be quite undetectable by conventional method. however, according to the rumor mill, they only use' em at night on holidays (heavy traffic). no flames, please, if in fact my rumor sources are completely out of touch. tony anthony m. petro "beethoven" i can say what i want; i'm just an undergrad V118HJ3D@UBVMSD.BITNET "soon the gypsy queen in a glaze of Vaseline petro@sun.acsu.buffalo.edu will perform on guillotine; what a scene, ..!uunet!acsu.buffalo.edu!petro what a scene..."
depolo@eniac.seas.upenn.edu (Jeff DePolo) (08/16/90)
>The police are "road testing" a new type of speed reader. They are >visible light based. > >Driver's Drawbacks To Date. > o Impossible to detect electronically. > o Dificult to spot. > o Imopssilbe to jam. > >Police Drawbacks To Date. > o Matte Black cars don't show up. The other disadvantage is that the current model can only be used from a stationary location due to the narrow (something like 6' diameter at 1000') beam produced, making aiming critical. Also, there is no "ground scatter" like there is with a conventional radar gun, so determining crusier speed in a moving situation would be impossible. --- Jeff -- -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- Jeff DePolo N3HBZ Twisted Pair: (215) 386-7199 depolo@eniac.seas.upenn.edu RF: 146.685- 442.70+ 144.455s (Philadelphia) University of Pennsylvania Carrier Pigeon: 420 S. 42nd St. Phila PA 19104
adam@chaos.cs.brandeis.edu (The invertebrate punster, so slug me.) (08/16/90)
In article <26c63bee-32e.10sci.electronics-1@vpnet.chi.il.us> cgordon@vpnet.chi.il.us (Gordon Hlavenka) writes: >One other note here. The way radars work is that waves are bounced off of >cars and the frequency is changed depending on how fast the car is going. >The radar measures the shift and approxiamates how fast the car was going >according to how much of a shift occurred. Conceivably, you could build >a AECM unit that would detect the incoming frequency and broadcast back >some other frequency to fool the detector. Of course, you would still have >the bounced frequency mixed in, so I'm not sure how well it would work. The police are "road testing" a new type of speed reader. They are visible light based. Driver's Drawbacks To Date. o Impossible to detect electronically. o Dificult to spot. o Imopssilbe to jam. Police Drawbacks To Date. o Matte Black cars don't show up. Question on radar. Has anyone designed the stealth buick yet? adam@chaos.cs.brandeis.edu --
jws@thumper.mlb.semi.harris.com (James W. Swonger) (08/17/90)
Once the LIDAR specs are known, couldn't the things be spoofed by, say, a forward aimed laser diode with a medium beam divergence pulsed at the right frequency? This plus an IR detector might give enough warning time while the LIDAR is trying to figure it out.
peter.saulesleja@f630.n250.z1.fidonet.org (peter saulesleja) (08/17/90)
> > Why would anyone intelligent enough to build a radar jammer > want > to risk several felony charges and at least one federal > offense to > get out of a $35 traffic ticket. Anyone with the skills > to build > this has a high probability of seeking work with defense In Ontario, 30 Kilometers per hour over the limit costs you $116, and 4 points off of your license (you have 15, lose them all, and you'll be taking the bus for a loooong time....) -=Peter Saulesleja=- Still, it's not a good idea. --- Opus-CBCS 1.13 * Origin: Nowhere(833-2814) "I hate origin lines!" (1:250/630.0)
bbesler@vela.acs.oakland.edu (Brent Besler) (08/18/90)
I think the device being refered to is that made by International Measurement and Control in Littleton, Colorado. The only practical way to use it in moving mode would be to wire it into a caibrated speedometer to determine the police cars speed. Aleo since the device needs to be aimed through a rifle like sight, a cop would need to be driving while another operates the device. I also believe it works in the near infared frequency range, so it isn't visible.
jp@frog.UUCP (John Pimentel) (08/29/90)
In article <1990Aug15.230142.25956@xrtll.uucp> chris@xrtll.uucp (Chris Baisley) writes: >In article <6141@tekred.CNA.TEK.COM> vekurpan@tekred.CNA.TEK.COM (Vincent E Kurpan) writes: >>QUESTION: >> >>Why would anyone intelligent enough to build a radar jammer want >>to risk several felony charges and at least one federal offense to >>get out of a $35 traffic ticket. Anyone with the skills to build > >Well, because, at least in Canada, a $35 speeding ticket is more >like $200. And that is only the start, because you will get a >'line' (a printed report) on your driving record, which will without >a doubt raise your insurance rates. The fine itself is fairly >inconsequential, it's the other ramifications. While in Massachusetts, a $35 speeding ticket was actually $50 at all speeds until it went up to $50 for the first ten miles and $10 for each mile thereafter. The charge hit the driving record where it stayed for three years until "you" were good for one year then it dropped off [on the anniversary all charges would drop one point, when everything was ZERO, then the lot would drop]. Now, it remains on for seven years with a increase of 7.5% (?) of compulsory and collision insurance [and some others] for each point above 15 pts [15 being middle -- 9 the lowest 35 the highest (Guess where the state wants you :( -- range]. Good drivers were given a credit of 3 pts for every year they were good to the maximum of 6 pts. Bad drivers were assessed. Some good drivers who received "Good Driver Credits" last year were charged this year when the window was blown open. Traffic == 2 pts Minor Accident == 3 pts Major " == 4 pts [also I think DUI falls here] One point off for every year that "you're" good. That's why any idea to get around the "highway robbery" is a good idea. Legality is for the courts to decide. -- ------------------------------------------------------- John Pimentel ...!{decvax!mit-eddie!harvard}!frog!jp Disclaimer: The opinion presented, is just that; I take full responsiblity for those parts I've entered. -------------------------------------------------------