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Radar generator to impersonate police radar
February 20, 2013 11:40 AM   Subscribe

I would like to have an inexpensive unit in my car that puts out a radar signal. I don’t want to spend a lot because I don’t want to measure the speed of anything. I just want other drivers on the highway with radar detectors to think there is police radar in the area, so that they slow down. I don’t know much about this, and I am afraid that a cheap radar gun puts out a signal in one direction only and won’t activate radar detectors all around me. Also, if there is a less expensive way to generate the appropriate radar-like radio waves, that would be better. Does anyone know of a method of fooling people with radar detectors so that they slow down?
posted by sitecoach to Travel & Transportation (28 answers total)
 
Transmitting anything in the police radar bands could be construed as jamming, and would be something that the police and FCC don't have much of a sense of humour about.
posted by scruss at 11:45 AM on February 20, 2013 [22 favorites]


I have seen such a product in the past, it mounted on your dash, then you'd press a button and "be entertained watching everyone around you suddenly slow down as their radar detectors trigger."

But a quick google failed me, so it may no longer be available if it ran afoul of any FCC regulations.
posted by jpeacock at 11:48 AM on February 20, 2013


If this is a consistent problem on one particular road or in one particular area, you might consider calling the police non-emergency number and reporting it.
posted by box at 11:51 AM on February 20, 2013 [4 favorites]


This sort of thing assumes that enough drivers use radar detectors that emitting a radar signal would slow down a significant number of cars around you. Is radar detector adoption significant enough in your area that such a device would really have a substantial impact?
posted by smoq at 11:52 AM on February 20, 2013 [2 favorites]


This is going to create much, much more of a problem than it solves, both for you and for others. You are not the police; do not impersonate them. If you can't handle highway driving, take the bus.
posted by Inspector.Gadget at 11:54 AM on February 20, 2013 [16 favorites]


This Agilent product, will generate pulses in the correct frequency range to (sorta) simulate police radar. Besides being more expensive than a car I'm not sure it will actually make a fake radar signal. You'd have to learn quite a bit about extremely technical and probably proprietary details like PRF and Chirp as well as carefully reading the spec of the sig gen to see if it will in fact generate that wave shape. Good luck....
posted by Confess, Fletch at 12:00 PM on February 20, 2013


There are lots of sports radar guns on Amazon. Not sure if they trigger detectors, though.
That said, using them on the road to mimic police radar will probably result in bad things happening.
posted by Thorzdad at 12:02 PM on February 20, 2013 [2 favorites]


This is illegal. Google "radar jammers" for the background. You cannot broadcast unlicensed radio frequencies.
posted by hwyengr at 12:04 PM on February 20, 2013 [4 favorites]


Older radar detectors used to be set off by the motion detectors that trigger the automatic doors in front of supermarkets and suchlike. You could hack something out of that, but I'd be highly willing to bet that you'd be violating aforementioned FCC rules if you went a whole lot further. You might have more luck fooling drivers by purchasing and driving a Lumina or Crown Vic with a couple of extra antennas on the trunk.
posted by jquinby at 12:05 PM on February 20, 2013 [1 favorite]


Seconding smoq. Who has a radar detector anymore?
posted by JoeZydeco at 12:06 PM on February 20, 2013 [1 favorite]


Add to the above issues that most police use LIDAR (Light Detection And Ranging) rather than Radar, and that's what most detectors are looking for now, even if you got a system working, you're probably not going to have much effect.
posted by Morydd at 12:07 PM on February 20, 2013 [1 favorite]


You might want to consider that having people around you unpredictably slamming on their brakes all the time would not be a good thing for you.
posted by empath at 12:19 PM on February 20, 2013 [2 favorites]


I am afraid that a cheap radar gun puts out a signal in one direction only and won’t activate radar detectors all around me

To clarify, you want people in front of you; people behind you; people passing you; people you're passing; and people going the opposite direction on the highway; all to slow down?
posted by ftm at 12:23 PM on February 20, 2013 [1 favorite]


Add to the above issues that most police use LIDAR (Light Detection And Ranging) rather than Radar, and that's what most detectors are looking for now, even if you got a system working, you're probably not going to have much effect.

I don't think this is true; my understanding is that most modern radar detectors still look for K and X band transmissions, though some drivers ignore them. If you transmit on Ka, you will likely get reactions. It may still be a bad idea for reasons discussed above.

Some suggestions came up when the same question was asked here.
posted by craven_morhead at 12:24 PM on February 20, 2013


Thirding smoq. A radar detector? How very 1980s.
posted by Rash at 12:39 PM on February 20, 2013


If this is this over a certain area or roadway and during a certain time period of the day or week, maybe you could contact a non-emergency police number and explain your concern. This way, you don't have to break any FCC regulations or spend any money on a questionable device.
posted by Giggilituffin at 12:42 PM on February 20, 2013


Very few people have radar detectors. It is a Very Bad Idea to impersonate the police.

Your time and money would be better spent on highway driving lessons.
posted by ewiar at 12:46 PM on February 20, 2013


Oh, jquinby is totally on the dot about looking like a cop- having a neutral colored, clean Crown Vic/Lumina or possibly a Charger/New Taurus with antennae will have more of effect on traffic than emitting a radar signal.

Those who use radar/laser detectors to avoid being detected for speeding are more likely to slow down for a speed camera, Ka or Laser signal, rather than slowing down for the K or X signals that cruddy, leaky radar detectors emit, as well as automatic doors, and other devices. So sure, if you were knowledgeable enough about radar signals and electronics, you could acquire or make a device to convince speeders to slow down, but then you'd be breaking US law.

It never hurts to brush up on defensive driving basics. No such thing as too much situational awareness, either. Best of luck.
posted by Giggilituffin at 12:54 PM on February 20, 2013 [1 favorite]


> Does anyone know of a method of fooling people with radar detectors so that they slow down?

If your goal is a safer driving experience for yourself (and others), this may not have the desired effect. Drivers don't necessarily just gently slow down when they think they're within range of a highway cop -- they drive more unpredictably and are highly distracted. They slam on their breaks, they change lanes, they crane their necks peering around to see if a cop is stationed on the side of the road, they squint at all the cars around them on the road trying to glimpse whether one of them might be an unmarked patrol car...
posted by desuetude at 12:57 PM on February 20, 2013 [2 favorites]


Oh, jquinby is totally on the dot about looking like a cop- having a neutral colored, clean Crown Vic/Lumina or possibly a Charger/New Taurus with antennae will have more of effect on traffic than emitting a radar signal.

As desuetude has just noted, this is not necessarily a desirable outcome. You look to increase the predictability of driving behavior to improve safety; anything that startles or annoys others is a Bad Thing.
posted by Inspector.Gadget at 12:59 PM on February 20, 2013


Are radar detectors themselves even legal in your area? If not, why would impersonating a police radar signal make any difference in other people's driving?

And yeah, sending out a signal designed to impersonate the police..... bad idea.
posted by easily confused at 1:42 PM on February 20, 2013


Regarding the Agilent signal generator mentioned by Confess, Fletch above -- that was a product I worked on :).

You are going to need an antenna and an amplifier and probably a bunch of other stuff in order to get that signal to the level it will trigger a radar detector.

Plus, as others have mentioned, it is probably an illegal transmission.

Plus, you might interfere with legitimate police radar used by someone who might actually give those people a ticket.

It is an interesting idea though :)
posted by elmay at 1:45 PM on February 20, 2013


A sport radar may work, depending on the frequency range.
posted by FauxScot at 2:03 PM on February 20, 2013


Lobby your jurisdiction for speed cameras.

In areas where speed cameras are consistently used near me, everyone slows down reliably.

This may not make you popular, but it could be a great sell for a jurisdiction looking to raise cash if they can also point to citizen requests.

(This post does neither endorses nor condemns speed camera use.)
posted by mercredi at 2:35 PM on February 20, 2013


Many of the sport radars will work for this. You can also modify some microwave motion detectors with a new oscillator (tangential discussion here and here) to get the desired effect if you are handy (though this is probably an offence for operating an unlicensed radio transmitter). It's a bit of a stretch for the cops to claim you are impersonating a police officer by merely measuring the speed of passing cars (though if anyone has an example of this I love to hear about it). It may however be explicitly illegal in your jurisdiction to operate a radar from a moving vehicle though so you might want to check with a lawyer. Also many of the anti-cell use laws actually prohibit using any electronic device and you might get tripped up by that. Finally your radar will trigger radar detector detectors which will cause a hassle for you if radar detectors are illegal in your area.

As someone who uses a radar detector off and on I can tell you that your plan won't fool anyone but the most gullible of detector users. Users of radar detectors are looking for intermittent pulsed signals. A continuous radar signal like you propose to broadcast looks nothing like a cop using radar to speed check cars.

JoeZydeco: "Who has a radar detector anymore?"

Lots of people. Enough so that cops in some areas still work their detector detectors.
posted by Mitheral at 6:55 PM on February 20, 2013


Pretend you're a cop. You know that radar is a tool in your arsenal, but not the only tool. You can still ticket people on eyeballs alone, with or without your radar gun.

A car is approaching. Looks like it's going fast. You raise your radar gun.

The gun, which has worked perfectly all day, suddenly stops working. As the car goes past you, you notice something funny on its dashboard. You quickly radar another car. Suddenly, your gun works again.

Whaddya think? Gonna pull this guy over for a looksee, or what?
posted by Cool Papa Bell at 7:14 PM on February 20, 2013


You need a Ka band radar gun. Here is a used one on ebay for $400, best deal I could find.

http://www.ebay.com/itm/Kustom-Signals-Eagle-KA-Band-Police-Radar-Gun-with-2-Antennas-Remote-Control-/140910988494?pt=LH_DefaultDomain_0&hash=item20cef30cce

Designed for car mount, front and rear antennas. My guess is if you lit this up you'd see a bunch of brake lights.

The x and k-band sports guns are unlikely to be be very effective, most people disable or ignore these bands on their detectors, otherwise you get too many false alarms.
posted by cosmac at 11:48 AM on February 21, 2013


Go for the good stuff and pick up a Stalker 2x:

The most advanced and easiest to use Police Traffic Radar just got better.
The Stalker 2X is actually two independent radar units operating on a single, 5-window, multi-color display


http://www.stalkerradar.com/law_2X.shtml

This should be able to cover both lanes as well as in front and behind you.
posted by coolxcool=rad at 10:47 AM on February 22, 2013


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