Half a croissant, on a plate, with a sign in front of it saying '50c'
h a l f b a k e r y
You gonna finish that?

idea: add, search, annotate, link, view, overview, recent, by name, random

meta: news, help, about, links, report a problem

account: browse anonymously, or get an account and write.



Mechanical radar Bamboozler

Give radar guns a false low reading
  (+10, -4)
(+10, -4)
  [vote for,

Based on how much y’all loved the fake seatbelt I’m a bit skittish about setting this thing out, but here goes...

What about a mechanical radar bamboozler. I’m not talking a radar scrambler. Wadded up aluminum attached to your wheels will do that. The police will get you for that in some places. As soon as they fail to lock onto you they know something is wrong. I’m talking about a mechanical device that will let the radar gun lock-on, but give a false reading.

An orthogonal inside corner reflects electromagnetic waves back at the source. If one were placed on a car it would give out such a bright reflection as to wash out any other signal. Reflectors like these are used today to help find life rafts. They are part of the emergency kit. A signaling balloon is tethered to the raft and the reflector dangles under the balloon producing a radar cross section the size of a battleship.

First place a device not unlike those used to measure the wind speed on your car. Small one on the bumper should suffice. Then place small reflectors about half way back the arms of the spinner and that should do it. The reverse motion of the spinning “wind gage” will cause the reflectors to be moving away from the radar source when ever the reflecting side is pointed towards the radar gun. You can even choose what percent to take off of your speed reading by where you place the reflector. Close to the hub, almost no change, close to the outside of the rotating arm gives close to 100% reduction.

So, is there a place for us anarchists or not?

Ozone, May 26 2008

Anemometer http://en.wikipedia.org/wiki/Anemometer
[afinehowdoyoudo, May 31 2008]


       True anarchists don't own thermoses. But I give it bun. Ah, but anarchists DO use the word bamboozle.
plynthe, May 26 2008

       Surely this thing would be moving fast enough that it would read as if you were going backwards?
phoenix, May 26 2008

       Not at all [phoenix]. Actually it is just about exactly like your tires. The part of your tire in contact with the road is actually going zero km/h while the top is going at exactly twice your velocity while only the center hub is going your posted speed. On the spindle, if it had perfect efficiency, ran on frictionless bearings, and any other adjustment to run perfectly, the central pivot/spin point would be traveling at your posted velocity while the outer ring would be either traveling at zero velocity, or twice your velocity. Making sure that you have it facing the correct direction so that it subtracts from your velocity rather than adds, placing the reflector at half the radius should give a reading of 50% of your speed. Outer rim, zero speed. Hub, actual speed.
Ozone, May 26 2008

       There was once a time when I could have really used something like this. Now, however, I no longer get my jollies tearing up the road.   

       Now I get my jollies driving two miles slower than the posted speed and really pissing the people off behind me.   

       Pastry to you sir, for finding new and exciting methods of foiling the fuzz, however.
MikeD, May 26 2008

       //a device not unlike those used to measure the wind speed on your car//
Hot wire?
AbsintheWithoutLeave, May 26 2008

       This would be a good idea if it was reversed: Make the reflectors run forwards so that the speed of the vehicle reads impossibly fast. I think the radar guns are designed to read the maximum velocity in the measurement field. If the OP's idea was followed, the radar gun would simply choose the signal from the rest of the vehicle and ignore that of the apparently slower reflector. +
Ling, May 26 2008

       I'll bun it just 'cause I want to see somebody driving along with a windmill whirling away on his hood.
elhigh, May 30 2008

       Don't worry too much about first ideas sucking. Like I say, half a bun is a good idea, two and a half buns are a miracle.   

       While I can see some potential for this to work, I doubt it will function as planned and, I feel the need to correct you on orthagonal inside corners.   

       These devices do give a clearly recognizable radar signature. However, their main benefit is from being located high above the water. With most radar, it is difficult to tell the difference between small waves and the hull of a ship, and rigging rarely shows up at all. A relfector placed on the rigging allows more reliable detection from greater distances, even when the rest of the ship is still hidden below the horizon due to the curvature of the earth.   

       As the back of cars contain a number of flat surfaces, and parabolic mirrors (tail lights, etc.) your orthagonal inside corners may need to be a larger size than assumed.   

       The size of these inside orthagonal corners (which can catch a lot of wind) will not prevent the proper working of your wind-speed measuring thing's (anenometer?) air-catching cups could be a problem.   

       I also suspect that these orthagonal corners may need to be many in number to function, and as they contain flat surfaces, some shielding may be needed to prevent the outsides from also registering a speed, or causing the whole to function exactly the same as tin foil wadded up and placed on the wheels... (Tin foil wads, by the way, also serve as rather effective radar reflectors for ships.)   

       All the same, good luck to you, kind anarchist, for I am always a fan of electricity-free devices intended to foil high-tech contraptions.
ye_river_xiv, May 30 2008

       If radar jamming was this easy then building a stealth fighter would be a snap. Something in the science is wrong here. A police radar detector is not like a radar imaging unit. The mechanism of police radar is the detection of a red shift/blue shift in the signal. The S/N ratio for such a device is very low and all that is measured is the maximum shift. Adding noise of a higher shift would increase the detected speed while adding noise of a lower shift would simply be filtered out.
WcW, May 30 2008

       ...so as Ling mentioned, get it to report an impossibly high speed, and they'll be forced to discard the reading.
Bukkakinator, May 31 2008

       All this talk of jam, and not a single bee.
4whom, May 31 2008

       is the velocity and surface and its reflective area great enough to trigger the gun's sensor? Would a oscillating high signal of low intensity be registered over a stronger stable frequency? Crucially would the device defeat pinpoint systems such as laser and narrow band radar used in most cameras and speed traps.
WcW, May 31 2008

       I disagree with the notion that agressive lawbreaking is anarchistic. Being an anarchist and being a self serving bastard are not the same thing. If you find a way to break the law but leave the law in place for the majority you are a sophist not an anarchist.
WcW, May 31 2008

       + for anything involving bamboozlement
afinehowdoyoudo, May 31 2008

       Imagine stealth to be the cloaking of vector, and not just the cloaking of scalar. Don't you think this may have been implemented if it worked? It is, after all the crux of your idea. Cloaking vector, that is, not that you were there in the first place.   

       Billions have been spent on the dispertion of radar from "orthoganal *outside* corners", or as close as they can get. It seems to have worked well, almost as well as if you were, instead of dispersing the signal, directing the signal straight back to the receiver, which is much easier to do.   

       You alluded to the radar cross section. That little bit of mathematics that averages the signal. As much as "orthoganal *outside* corners" difuse this cross section, your *inside* corners will exacerbate this cross section. This might, initially, result in readings that are too high, but will be mitigated over calibration. Mechanically, the only way to beat radar is to slow down! There are non-mechanical ways to beat it, but we know them already.
4whom, May 31 2008

       Someone has been watching Mythbusters reruns. This is not a new idea.
jhomrighaus, Jun 02 2008

       Out of curiosity, why is this not being concealed in the wheels, where the ratio change in speed to that of the spedometer could more easily be calibrated?
ye_river_xiv, Jun 02 2008

       [jhomrighaus,] Sorry, no Myth Buster reruns on this one. I have been working this idea many years. Long before Myth Busters aired.   

       [WcW] It is not noise that I want to add to the low end, but rather an overpowering signal.   

       To All; It should be easy for me to create a prototype of the device that I have in mind. I also know of a couple of places where the Police have stationary Radar displays. The type designed to let you know they are watching and know how fast you are going. I will see if I can gen up a prototype and see what my speed says as I approach their Radar display. I’ll keep you posted on the progress and results.   

       By the way, since stealth is out of the closet so to speak, I feel free to tell y’all that I was working on stealth before Jimmy Carter let it out of the bag
Ozone, Jun 02 2008

       hey, it occurred to me that your device will ADD to your apparent speed for a radar observer BEHIND your car. Also, your orthogonal reflectors should be reflective to lasers as well as microwaves.
afinehowdoyoudo, Jun 03 2008

       Bun for inovation (+), but I don't think it will work unless you drop the rest of the radar signature down a lot or you enlarge your reflectors to the point of general ridicule. You might do better with a powered system with belts and attached paddles. If you get stopped tell them you are testing the system to lower aerodynamic drag by reducing skin friction.
MisterQED, Jun 03 2008


back: main index

business  computer  culture  fashion  food  halfbakery  home  other  product  public  science  sport  vehicle