scrap a older superhetrodyne radar detector, you'll find plenty to play with, including a weak gunn diode and a decent detector diode, and yes can motionsense with it, up to about 5 feet, as that diode is set up for only a milliwatt or two. With a good IF you can differntiate male and female hip swing.
Steve Roberts
That is pretty much true. The only time you will have speed traps is when they are responding to a specific complaint and even that is rare. Central Florida has a horrible reputation for speed traps and particularly little shit holes like Waldo that use the speed trap as a major source of revenue. The cops in Lee county are not "speeder maids" . Sometimes the FHP will set up a speed trap on I-75 but that is usually the roving wolf pack, not the regular troop F guys. They usually bring a plane.
Parallax is exactly the same with radar or laser, it is simple trig. The same with calibration. The only reason laser is seen as being more accurate is that you are only shooting at one particular place on one car. There is less chance of getting a return from a non-targeted vehicle.
Florida is so notorious for speed traps that AAA trip maps are marked with the usual locations ;-)
...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC\'s and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
Yup but they are up in Cebntral Florida, particularly along the 301 connector between I75 and I95. That is where Waldo and Starke are. St Pete has a traffic unit and I imagine all of those big cities over on the blue coast do a lot of traffic but it is not that prevelent here in paradise. (Lee and Collier County) The one exception is another little shithole called North Port. They have a sliver of the city limits that crosses I75 and the city cops will sit out there. That is Sarasota County.
I hate the lazy bastards who sit at the bottom of a long hill.
Isn't Louisiana notorious for this sort of thing?
Jim Thompson wrote in news: snipped-for-privacy@4ax.com:
Florida loves speed traps because a percentage of the ticket fine gets transferred to the police agency writing the tix. It's far more profitable than writing other moving violations that require more work on the officer's part.(but make driving FAR safer!)
Central Florida enforces red light running only maybe three times a year,except for blatant incidents that startle the officers.
-- Jim Yanik jyanik at kua.net
Not if you fire it from further away, which is possible with laser.
Shakespeare said "For 'tis the sport to have the engineer Hoist with his own petar" (Hamlet III iv). But that was a long time ago 1604?).
On Thu, 26 Oct 2006 12:30:20 -0400, snipped-for-privacy@aol.com Gave us:
Bullshit. You do not even know what the term refers to.
With the laser, the target pointed at IS the target hit, and the returned light has absofuckinglutely zero error. With the radar, the field-of-view is the target and the returned result is that of the fastest moving element in the field of view. THAT MEANS that the cop can pull you over for a speed that another vehicle was traveling at. With automotive radars, THAT is what the term "parallax error" refers to.
In California, radar is not even used on freeways for this very reason. The only thing that holds up in courts out here is moving clock. They don't even use planes for speed determination. They use planes to spot asshole idiot drivers, and state troopers to nail their asses.
Radar gets used on surface/residential streets in the speed indicator machines. The cops use lasers, and they flag you over if you are there ticket target al la mode.
On Thu, 26 Oct 2006 12:30:20 -0400, snipped-for-privacy@aol.com Gave us:
Nope. It is because the light is coherent.
There is NO chance of getting such a "signal".
Try again.
On Fri, 27 Oct 2006 07:33:05 +1000, Clifford Heath Gave us:
You guys are both on the wrong track. Radar has an FOV. A laser resolver has a single target, and it ONLY ALWAYS has a single target.
Complete crap. Parallax error is error in measured speed due to the radar looking out from the side of the road at an angle. In my city, cops are taught to align the radar to aim 26 degrees from the line of the road, because that's the *parallax* error for which the units are calibrated.
Your points about FOV are perfectly valid - and parallax is unavoidable with radar because it has a wide FOV - but wide FOV != parallax. Parallax error is possible with lasers too, but can be avoided.
See for more details.
Crap again. Coherent light does not have to be collimated, and in fact laser diodes do *not* emit collimated beams, but divergent ones which are *approximately* collimated by a lense. The actual IR beam isn't used for sighting, either. A second visible beam is used for that, which hopefully points at the same target. And even really good lasers have a non-zero divergence, so that when we first used radar reflectors to measure the distance to the moon, the beam that hit the target was already *miles* wide.
Granted that this is not a problem with actual laser guns, but that doesn't hide the fact that your understanding is
*fundamentally flawed*.Plus, who can tell whether someone's using an optical chaff generator. It isn't hard to flash an LED or uncollimated LD of the right wavelength, flash length, and period, to completely baffle the laser gun so it either can't get a reading at all, or gets a wrong one. The receiver in these guns is nowhere near as directional as the transmitter, so this could come from another vehicle.
It still depends on the number of targets on the road. A K band radar will clock just about anything you can see on a long flat road.
Perhaps you should go to fire control school and find out a bit about what these terms mean. Parallax in the fire control problem represents the differennce between line of sight and line of fire so it really doesn't apply here at all but the closest thing to it is the difference between the angle of the beam vs the line of travel. The farther the radar is off the road the more error introduced. Unfortunately for the argument the error is in the favor of the speeder. This is the hypotenuse of a triangle. When the error angle is very low the speed indicated is fairly accurate but as range closes the angle increases and the indicated speed drops. When the angle is
90 degrees the indicaterd speed will be zero. You are shooting at the side of the car.The range of the reflected signal will vary greatly depending on the reflectivity of the target. Some cars don't reflect radar or laser well. They will have a very short effective range. If your state has a front plate or you have exposed headlights that becones a good target. There are cars with low radar or lidar profiles. Lidar can be somewhat jammed with very hot driving lights. It overloads the preamp.. Eventually when you get close they can get a clean target. The various car magazines do test this occasionally and report on different cars and deyection range.
These are the same cops who shot 81 rounds and only hit the suspect 27 times at point blank range. How do you think they can hit a license plate at half a mile and never miss?.
They can miss the intended target and score a direct hit on the wrong one?
And that's assuming that the sighting laser still points in vaguely the same direction as the speed laser...
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