peg@psuecl.bitnet (PAUL E. GANTER) (12/29/89)
Hey! I know the following may sound crazy--I am doubtful myself.
My stepfather was recently talking to a long-haul trucker at a truck
stop. The guy told a tale about blasting radar guns using a very simple
device. Apparently the guy had an ordinary fluorescent tube mounted
in a reflector, with no power applied. He had copper strip wrapped
around the tube with a regular spacing. He placed the device inside
his windshield facing forward, and when hit with a radar gun....
POOF!!
goes the radar gun. Now, granted, this sounds far-fetched, but maybe
the thing acts as a resonator?!? I don't know: I avoid microwave
stuff like the plague.
If anyone has heard a similar tale or wants to comment on the
possibilities, I would be interested. By the way, I have NO
interest in building this thing. I don't drive like a maniac.
The interest is purely academic.
Paulrandom@cbnewse.ATT.COM (Random @ rebmA) (12/30/89)
From article <74719@psuecl.bitnet>, by peg@psuecl.bitnet (PAUL E. GANTER): > Hey! I know the following may sound crazy--I am doubtful myself. > Your inherrent wisdom shines through. > My stepfather was recently talking to a long-haul trucker at a truck > stop. The guy told a tale about blasting radar guns using a very simple > device. Apparently the guy had an ordinary fluorescent tube mounted > in a reflector, with no power applied. He had copper strip wrapped > around the tube with a regular spacing. He placed the device inside > his windshield facing forward, and when hit with a radar gun.... > > POOF!! Since I know only basic theory, I'll be the first to come up with an explaination of how this might work (instead of all the reasons it can't). The 'reflector' was of a material and curvature/size ratio to properly focus a majority of the incomming microwave radiation on the (reasonably intact) fluorescent tube. The fact the the tube is unpowered is not relevant since that would just give us visible spectrum, and we need a microwave spectrum. But the phosphor coating in the tube would be Stimulated to Emit Radiation, and would therefore be a Microwave Amplifier. And we would call this device a . . . MASER, yea, thats the ticket. And I own, no make, no HOLD THE PATENT on it, yea, and I'm working a deal to sell it to. . . to Iran for a mil A BILLION dollars and be a hero like Oliie North who is my role model, no good buddy, no EMPLOYEE, yea. Random :^)
ee5391aa@hydra.unm.edu (Duke McMullan n5gax) (12/30/89)
In article <74719@psuecl.bitnet> peg@psuecl.bitnet (PAUL E. GANTER) writes: >Hey! I know the following may sound crazy--I am doubtful myself. > >My stepfather was recently talking to a long-haul trucker at a truck >stop. The guy told a tale about blasting radar guns using a very simple >device. Apparently the guy had an ordinary fluorescent tube mounted >in a reflector, with no power applied. He had copper strip wrapped >around the tube with a regular spacing. He placed the device inside >his windshield facing forward, and when hit with a radar gun.... > > POOF!! > >goes the radar gun. Now, granted, this sounds far-fetched.... Yea, verily, doth this indeed sound far-fetched. It sounds to me about on par with the gag of getting a toilet to explode by flushing a quart of turpentine. FWIW, a ham I know relates the tale of the time a cop pulled him over, and told him that the cop saw him start talking into his microphone (2 meter mobile rig, with a 75 watt RF power amp as an afterburner...this guy believes that power pays....) just as the cop's radar went ten-toes-up. My friend was puzzled, and had a look at the radar unit -- sure enough, it wasn't working. He shrugged and told the cop the only thing he could think of was that the IF might be close to the 2M band, and something in there had gotten cooked when he keyed his mike. The cop asked, "What's an IF?" After a basic introductory lecture on radio, the cop had a rough idea. He called my friend a couple of weeks later, and related that a note he had rec- eived from the factory when the radar was sent in for repairs confirmed that the IF was cooked, and the factory had no idea how it could have happened, even with a fairly hot transmitter on the IF frequency was going in the area. (The word "he" in this last paragraph refers to the cop. Please pardon the ambiguity.) There was a collective shrugging of shoulders, and nobody really knows why it happened. It had a nice side effect, though. If you listen to the right local repeaters, you can often hear that cop signing with his new call. d "You should never threaten a man you are not going to fight, and if war is your intention, it is best to get on with it." -- F.J. Lovret Duke McMullan n5gax nss13429r phon505-255-4642 ee5391aa@hydra.unm.edu
brian@ucsd.Edu (Brian Kantor) (12/30/89)
A reasonably large magnetron feeding a reasonably large antenna on the front of your car, wired up to a bank of capacitors charged by an inverter from the car battery, might be able to emit a pulse of 10 GHz or 24 GHz of sufficient magnitude to blow the mixer diode in the typical cop radar to glory-be. You'd clearly want to have it trigger off the radar detector mounted next to it, but shielded from it in some way. I've often contemplated building something like this, but since the local flic have only got 7 radar units in a town of over 2 million inhabitants, why bother? A 24GHz autolaunch homing missile with HEAT warhead would be much more effective. Just mount them in disguised trash containers and deploy them on busy streets.... Come to think of it, that's overkill. Just an Estes rocket with smoke cannister is sufficient. After all, you only want to scare them, not put craters in the sidewalk. Yes, I'm kidding. - Brian
peg@psuecl.bitnet (PAUL E. GANTER) (12/30/89)
In article <10657@ucsd.Edu>, brian@ucsd.Edu (Brian Kantor) writes: > > A 24GHz autolaunch homing missile with HEAT warhead would be much more > effective. Just mount them in disguised trash containers and deploy > them on busy streets.... Come to think of it, that's overkill. Just an > Estes rocket with smoke cannister is sufficient. After all, you only > want to scare them, not put craters in the sidewalk. > > Yes, I'm kidding. > - Brian Yee-hah! This is the kind of response I was looking for! Good old American ingenuity comes through. Seriously though, I have heard tales of HAM's jamming (not destroying) radar guns, and people putting magnetrons on their cars (effective birth control?). Anyway, what I wanted to know was how (in theory) the thing might work. Thanks for the entertainment! Paul
sampson@attctc.Dallas.TX.US (Steve Sampson) (12/30/89)
In article <74896@psuecl.bitnet>, peg@psuecl.bitnet (PAUL E. GANTER) writes: > Seriously though, I have heard tales > of HAM's jamming (not destroying) radar guns, and people putting > magnetrons on their cars (effective birth control?). Anyway, what > I wanted to know was how (in theory) the thing might work. > I haven't seen any magnetron jammers yet. Hams don't jam anything other than HF and at least one local repeater :-) However, what your looking for (inexpensively) is an AM jammer. The CW radar is looking for a Doppler Shift between its transmiter and receive target frequency. It uses a simple crystal diode radio. With enough power you can mask all other targets by modulating a carrier with the appropriate Doppler Shift for the microwave band in question. The crystal diode radio will then process only this shift. This works poorly against stationary radars and ineffective against moving radar. AM jamming is the worst selection in any radar technical book. A test by Car and Driver into the effectiveness of this type of jamming, proved that they didn't work. By the way, the next issue of Radio-Electronics claims to have a radar detector tester. Oh no... These will invariably end up on the turnpike and freeways with the mental midgets turning them on at various times to watch your radar detector lights. Masters and Johnson had a name for this, but I forget... Steve, N5OWK
peg@psuecl.bitnet (PAUL E. GANTER) (12/31/89)
In article <10781@attctc.Dallas.TX.US>, sampson@attctc.Dallas.TX.US (Steve Sampson) writes: > > I haven't seen any magnetron jammers yet. Hams don't jam anything other > than HF and at least one local repeater :-) However, what your looking > for (inexpensively) is an AM jammer. The CW radar is looking for a Doppler No, I am not looking for anything! I am not interested in building a radar jammer, I am interested in the theory/truth behind the device I described. > Shift between its transmiter and receive target frequency. It uses a simple > crystal diode radio. With enough power you can mask all other targets by > didn't work. By the way, the next issue of Radio-Electronics claims to have > a radar detector tester. Oh no... These will invariably end up on the > turnpike and freeways with the mental midgets turning them on at various times > to watch your radar detector lights. Masters and Johnson had a name for this, > but I forget... Maybe the cops will use them to scare you into going slower? Cheaper than actual radar guns, I'll bet.
henry@utzoo.uucp (Henry Spencer) (12/31/89)
In article <10781@attctc.Dallas.TX.US> sampson@attctc.Dallas.TX.US (Steve Sampson) writes: >... By the way, the next issue of Radio-Electronics claims to have >a radar detector tester. Oh no... These will invariably end up on the >turnpike and freeways with the mental midgets turning them on at various times >to watch your radar detector lights... With any luck the thing will have a sufficiently short range that this won't work. I think the FCC might object otherwise. When radar detectors first became popular, various police agencies were quite interested in putting permanent microwave emitters at strategic locations, to minimize usefulness of the detectors and generally slow down the traffic. The FCC refused to license such transmitters. -- 1972: Saturn V #15 flight-ready| Henry Spencer at U of Toronto Zoology 1989: birds nesting in engines | uunet!attcan!utzoo!henry henry@zoo.toronto.edu
markz@ssc.UUCP (Mark Zenier) (01/01/90)
In article <1989Dec30.221555.29156@utzoo.uucp>, henry@utzoo.uucp (Henry Spencer) writes: > In article <10781@attctc.Dallas.TX.US> sampson@attctc.Dallas.TX.US (Steve Sampson) writes: > >... By the way, the next issue of Radio-Electronics claims to have > >a radar detector tester. Oh no... These will invariably end up on the > >turnpike and freeways with the mental midgets turning them on at various times > >to watch your radar detector lights... > > With any luck the thing will have a sufficiently short range that this won't > work. I got my copy on friday. A MRF901 oscillator at a claimed 1169.44 Mhz with the 9th harmonic of 10.525 Ghz, Using a PC board tuned circuit. (Yea sure) The claimed range is 12 feet. I'm surprised they didn't publish this in April. > I think the FCC might object otherwise. That never stopped Radio Electronics. The fuss that got raised after their article on a UHF channel transmitter for home video cameras was amusing. markz@ssc.uucp
dclaar@hpcupt1.HP.COM (Doug Claar) (01/03/90)
>a radar detector tester. Oh no... These will invariably end up on the >turnpike and freeways with the mental midgets turning them on at various times >to watch your radar detector lights... > ---------- Well, hm. Mental midgets, huh? I've always thought that it would be great fun to do just that when you see some jerk that thinks he can do 100 mph just because he has a radar detector. I'm just glad to see that the REAL mental giants spend their time figuring out how to foil someone trying to actually enforce the law. Wow, what a concept. Yup, now how about articles on how to foil those annoying ATM machines that have such an unreasonable restriction on using someone else's account? Now that would be time well spent. Doug "Who, me? Sarcastic? Not at all! Why do you ask?" Claar
kenmoore@unix.cis.pitt.edu (Kenneth L Moore) (01/04/90)
In article <74896@psuecl.bitnet> peg@psuecl.bitnet (PAUL E. GANTER) writes: >In article <10657@ucsd.Edu>, brian@ucsd.Edu (Brian Kantor) writes: >Anyway, what >I wanted to know was how (in theory) the thing might work. > >Paul While I was in the military we had a device that would amplify incoming radar waves and beam them back to the receiver. Since the receivers are set up to expect maybe 1 millionth of the transmitted power reflected back, they are very sensitive and the amplified waves would blow out the receiver. Of course, this only worked on very primative radar receivers with no overload protection. I don't know if smokey has overload protection, but it should at least jam the radar. Of course the best bet is to drive under the speed limit. -- I don't yell and I don't tell and I'm gratefull as hell. Benny Hill.
feg@clyde.ATT.COM (Forrest Gehrke,2C-119,7239,ATTBL) (01/05/90)
In article <10657@ucsd.Edu>, brian@ucsd.Edu (Brian Kantor) writes: > A reasonably large magnetron feeding a reasonably large antenna on the > front of your car, wired up to a bank of capacitors charged by an > inverter from the car battery, might be able to emit a pulse of 10 GHz > or 24 GHz of sufficient magnitude to blow the mixer diode in the typical > cop radar to glory-be. You'd clearly want to have it trigger off the > radar detector mounted next to it, but shielded from it in some way. There are a few problems with this: Discharging a bank of capacitors results in only a single pulse of energy whose average may not be particularly high, but whose duration may be too long for most pulsed type maggies. Secondly, that voltage has to quite high (most pulsed type maggies are measured in kv). Thirdly, the heater voltage for the cathode would have to be on continuously and the life of these tubes is not particularly outstanding. Most of the surplus maggies in the X band range are pulsed type and it might be a better idea to actually arrange to pulse them with a train of pulses. The 2J42 would be a good candidate and probably fairly cheap. As for K band, even a surplus maggie might be out of sight for cost. Probably a lot cheaper to buy an Escort fuzzbuster (;-)) I have often thought of going the spoofing ECM route: get hold of a small X band TWT and arrange to retransmit the radar information back to the radar receiver, but having first processed that information to make it look like your are moving 25 mph. That should make an interesting sight to see the jaws drop as you glide by at 90 mph! Forrest Gehrke clyde!feg
crisp@mips.COM (Richard Crisp) (01/05/90)
I do remember seeing an article in "Radio Electronics" circa 1985 to 1987 that described a "false target generator" for police RADAR. This project was the featured article in the issue and was shown on the cover. In essence it would allow you to jam a RADAR gun with a signal that would trick the RADAR gun into saying that you were going a speed of your choice (like 55mph). It was an interesting project as I recall and only had one expensive component, the GUNN diode (the microwave source). -- Just the facts Ma'am
mikemc@mustang.ncr-fc.FtCollins.NCR.com (Mike McManus) (01/05/90)
In article <34143@mips.mips.COM> crisp@mips.COM (Richard Crisp) writes: > I do remember seeing an article in "Radio Electronics" circa 1985 to 1987 that > described a "false target generator" for police RADAR. This project was the > featured article in the issue and was shown on the cover. In essence it would > allow you to jam a RADAR gun with a signal that would trick the RADAR gun into > saying that you were going a speed of your choice (like 55mph). It was an > interesting project as I recall and only had one expensive component, the GUNN > diode (the microwave source). > > -- > Just the facts Ma'am Seems to me that I recall hearing a story about a guy who built himself such a beast (wish I could add details, but it was a 3rd or 4th-hand story). One day he gets pulled over in a school zone for speeding. "Clocked you going 55 in the school zone", says the cop. Well, he started to protest violently (he *KNEW* he was only doing 20!), but then shut up and took the ticket. You see, he realized that he was screwed: he had accidently flipped on his "jammer", set to say he was doing 55... -- Disclaimer: All spelling and/or grammer in this document are guaranteed to be correct; any exseptions is the is wurk uv intter-net deemuns. Mike McManus (mikemc@ncr-fc.FtCollins.ncr.com) NCR Microelectronics 2001 Danfield Ct. mikemc@ncr-fc@ncr-sd.sandiego.ncr.com, or Ft. Collins, Colorado mikemc@ncr-fc@ccncsu.colostate.edu (303) 223-5100 Ext. 360 (they're ugly, but they work!)
crisp@mips.COM (Richard Crisp) (01/05/90)
Along the lines of the discussion of RADAR jamming/blasting, I recall a funny comment an M.E. friend of mine that worked on the F16 project at G.D. once said. He told me how some of his buddies at G.D. were putting RAM on the front of their cars to help elude RADAR traps. I asked "gee why RAMs?". After a bit of discussion, we came to the conclusion that to an M.E. RAM does not mean the same as it does to an E.E. To an M.E. (working on the F16) RAM = Radar Absorbent Material To an E.E. (particularily a digital I.C. designer) RAM = Random Access Memory. I thought it was a bit humorous, I hope you folks do too. -- Just the facts Ma'am
gd@milkfs.itstd.sri.com (Greg DesBrisay) (01/06/90)
>In article <10657@ucsd.Edu>, brian@ucsd.Edu (Brian Kantor) writes: > A reasonably large magnetron feeding a reasonably large antenna on the > front of your car, wired up to a bank of capacitors charged by an > inverter from the car battery, might be able to emit a pulse of 10 GHz > or 24 GHz of sufficient magnitude to blow the mixer diode in the typical > cop radar to glory-be. You'd clearly want to have it trigger off the > radar detector mounted next to it, but shielded from it in some way. Reliable rumor has it that some folks did just what you are suggesting, but instead of the magnetron they used a spark plug! The spark plug was mounted in a tuned cavity which was in turn coupled to a horn antenna. Back in the early days of police radar, they filled the back end of an automobile with capacitors (and in those days there was a lot of room in the back of an automobile), charged up all those capacitors, and then, as they drove by an unsuspecting "target", they discharged the capacitors all at once through the spark gap. They left more than a few radar operators scratching their heads, wondering why their radar unit suddenly failed, but decided to curtail their activity before someone associated the failure of the radar units with the loud shotgun-like bang that happened whenever they threw the switch on their spark gap! Greg