Radar Gun Fundamentals

[JoeBloe]

Crap again. Coherent light does not have to be collimated,
and in fact laser diodes do *not* emit collimated beams,

They do once they pass through the optics, you retarded ****. Any
laser bench setup (which these are even at the micro-size level they
are at) has optics.

When such light hits the target, very specific reflection are noted.
The range finders use a serial pulse to determine distance, and do so
quite accurately. The speed determining circuitry in the police
variant of that same range finder is not plagued by ANY error
producing problems. They are dead accurate, and do not need any
calibration on a per use basis as radars do. They get calibrated at
the factory, and periodic verifications of that calibration are made
in service.

Radars require calibration before each shift that intends to use
them. Said calibration is done with an audible tuning fork device.

but divergent ones which are *approximately* collimated by
a lense.

You're an idiot. No one is arguing basic laser optics here,
dumbfuck.

The actual IR beam isn't used for sighting, either.

There is no IR beam. They are aimed optically by the user.

A second visible beam is used for that, which hopefully
points at the same target.

A single beam is used, and it is in the visible spectrum.

And even really good lasers have
a non-zero divergence,

Go teach some elementary school kids your basic crap. You aren't
enlightening anyone here, and we don't need your primer.

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.

That's funny.

The EARLY lasers that were pointed at the moon were indeed miles
wide by the time they got there. Much less so now with the better
lasers that we have for that purpose.

Granted that this is not a problem with actual laser guns,
but that doesn't hide the fact that your understanding is
*fundamentally flawed*.

You're fundamentally full of shit.

Plus, who can tell whether someone's using an optical chaff
generator.

You're an idiot.

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

No, it is nearly impossible, actually.

so it either can't get a
reading at all, or gets a wrong one.

Wrong. They pulse a data stream. They capture the stream on return.
If a "bad" stream is encountered, the test runs again. It doesn't
make a determination with errant data, it runs the routine again,
until it gets verifiable data.

The receiver in these
guns is nowhere near as directional as the transmitter, so
this could come from another vehicle.

You're an idiot. The pulse train sent by the laser in the gun is
the pulse train it detects coming back. It ignores all your "false
fool it" baby bullshit, and any other crap you make up. It has
nothing to do with directionality of the receiver. The field of view
of the receiver is very narrow in fact. Less than one degree.

 

[JoeBloe]

Perhaps you should go to fire control school and find out a bit about
what these terms mean.

Perhaps you should **** off.

Parallax in the fire control problem

This has nothing to do with fire control, you retarded twit.

It has to do with a group of cars, and the human error of a cop
choosing a car that was not the fastest car in the pack.

represents
the differennce between line of sight and line of fire so it really
doesn't apply here at all

Funny that you have even proven yourself to be stupid.

but the closest thing to it is the
difference between the angle of the beam vs the line of travel.

You're an idiot. The difference is negligible and the industry has
done nothing to deal with it since it is negligible. Radar guns are
VERY accurate. The problem is when there are several cars in a pack
of moving cars. The radar only details the top speed in the test
window, it does not determine the culprit. Laser guns ONLY give the
speed of the target vehicle they are applied to.

THAT is the difference.

The
farther the radar is off the road the more error introduced.

Bullshit. They detect perpendicular crossing traffic speed as well
as ANY angle of incidence to the target FOV as well as any directly on
axis targets. Pretty much blows your bullshit, ass zit from sittin'
on it too much made up theory right out of the water.

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.

Again, you're an idiot. The speed of the EM pulse is far faster
than the targets they are capturing reflected data from The
difference is less then a single MPH throughout the spectrum of
variance you piss and moan and make shit up about.

When the angle is
90 degrees the indicaterd speed will be zero.

Total proof that you are a big fucking dope. Radar guns work just
fine on perpendicular crossing traffic.

You are shooting at the
side of the car.

Nope. The gun shoots at a field or window of sensitivity. Any moving
object in that window get pegged multiple times, and its speed is
determined no matter where it resides in the field of sensitivity, nor
what direction it is traveling in said field. With the laser, a
specific car is targeted, and it is that car's speed that gets
reported, period. No matter where the car gets "shot" at or from.

The range of the reflected signal will vary greatly depending on the
reflectivity of the target.

Also a non issue. Radar guns can work effectively out past a half
mile range, and none are used at those lengths so you are again lost.

Some cars don't reflect radar or laser
well.

You're a total dweeb. You went through your entire life making crap
up.

Just so you know... you have been doing a poor job of it.

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.

You're an idiot. Radars work. Lasers work. One is 100% accurate,
the other is 100% accurate but doesn't define the target in multiple,
group element settings. That is its only flaw.

There are cars with low radar or lidar profiles.

I have a bridge in Brooklyn I can sell you.

Lidar can be somewhat
jammed with very hot driving lights. It overloads the preamp..

Dude, you have been reading too much bullshit, and then you make up
your own to add.

Eventually when you get close they can get a clean target.

When do you get the autoclave?

The various car magazines do test this occasionally and report on
different cars and deyection range.

Dude. You're full of shit, and you need help spelling.

 

[JoeBloe]

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?.

You're an idiot. One thing, they don't half to hit a license plate,
nor do they have to do so at a half mile range.

Also, a laser is a constant beam and can be accurately aimed over
several miles. There are planes over Iraq right now that can track
and lase 100 targets at one time from several tens of miles away.

Give it up, dumbass.

 

[JoeBloe]

They can miss the intended target and score a direct hit on the wrong
one?

No. You're an idiot. "Score a direct hit" is proof of that.

They are optically "scope" aimed, and then the test (trigger) is
actuated. The aimed at target is the only target struck, and the test
doesn't produce a readout if the test didn't proceed correctly.

 

[JoeBloe]

You can with radar - they were notorious for that.

Wrong, you retarded twenty blank lines after every post twit!

The radars NEVER had targets. They ALWAYS had a FOV (field of view)
or FOS Field of Sensitivity. Lasers are the only devices that have
ever had specific targets.

That means that BY DESIGN, they only report the fastest element
moving in said field during said test run. "Test" means "use".

What they were notorious for is the stupid cop picking the wrong
target (moving element) as the culprit for the speed reading garnered
from the gun's use..

 

[JoeBloe]

Does the radar automatically correct for the angle?

Yes. However, at the speeds cars travel, the error generated is
less than a single MPH. If the targets were mach speed jets, the
error would be more than negligible. With this scenario, it is 100%
negligible.

 

[JoeBloe]

JoeBloe is ignorant ;-)

What I should be ignoring is retarded posts like this one that makes
claims, yet provides zero backing for them.

Tell us, oh guru of RF emissions, what error is introduced in a test
result of 60 MPH with a car moving at 60 MPH.

At one degree angle of incidence:

At ten degrees:

At 45 degrees:

At 90 degrees:

The pulse goes out at the speed of light (nearly) and is actually a
serial train of pulses. Several pulse trains are sent during a single
test, and the doppler electronics inside the gun perform the
deterministic result.

So tell us, asshole... What amount of error can we expect to see
for sub 100 MPH cars?

What amount of error would we expect to see for mach speed jets
passing into the field of sensitivity for the device?

Can't answer those questions? Then **** off, asshole.

 

[JoeBloe]

A guy with a good radar
detector can easily "frame" an innocent driver by slowing down at the
right time and making the guy going the legal speed look like the bad
guy.

You're an idiot.

The cop is supposed to observe the driving habit of the suspect as
well.

 

[JoeBloe]

It can only measure
direct closure (or its opposite) between the gun and the target.

Absolutely false.

 

[JoeBloe]

And a laser can still get the wrong
vehicle, it depends on how good the aim of the user is...

Absolutely false!

A laser has only one target, and that target is optically selected
by the cop. There are no errant target selections with the laser gun.
And getting it right is quite easy, and they do not shift targets
during the sampling. Aiming a laser is easier than pointing your
fucking finger.

 

[JoeBloe]

Ignorance isn't a vice, it simply means "I do not know".

Said "Bobo the Chump" Instead of providing any information about
the actual topic.

When one who is ignorant refuses to learn, then it becomes stupidity.

Which is clearly your case.

Unfortunately, Society has been in conflict with Nature here - stupidity
in Nature is a terminal disorder, but then Society started protecting the
stupid from the consequences of their own stupidity, and they've been
breeding like flies ever since.

That only due to the fact that we are nice, and that is the only
reason fly like retarded fucks like you are still around.

And voting.

Not in Florida.

Why do you post under so many different monikers, you retarded ****?

Instead of peanut gallery commentary, you should try actually
posting something about the actual topic of the threads you invade,
you retarded ****.

 

[JoeBloe]

You are taking his word alone no matter what. The gun does not take a
picture or anything. It is only his word about what it read and which
car he was pointing at. They don't let you get out of your car and go
look at the radar.

Actually, that is the very thing that cops in many states do.

The one time I was cited for speed by radar, I was shown the reading
on the gun.

 

[JoeBloe]

The pulse train has a header in each test frame. All falsely
generated light pulse trains are ignored.

The problem is "so what" the fcc does not regulate IR transmissions.

No, but the FAA does. Try pointing your simple laser pointer at the
county sheriff's helicopter next time it passes over, and see what you
get charged with.

Also, it is not called a transmission. With light, it is referred
to as radiation, or a radiant emission.

 

[Jim Yanik]

The problem is "so what" the fcc does not regulate IR transmissions.

But many state laws do.
Even if just called "interfering with police enforcement".

 

[Jim Yanik]

[email protected] wrote in

You are taking his word alone no matter what. The gun does not take a
picture or anything. It is only his word about what it read and which
car he was pointing at. They don't let you get out of your car and go
look at the radar.

Then one has to ask why the speed measurement guns do not print out a
receipt/ticket for evidence?? It's not difficult to do these days.
They could even include a .jpg of the target vehicle,with the data at the
bottom,like a date/time stamp.

 

[Spehro Pefhany]

[email protected] wrote in


Then one has to ask why the speed measurement guns do not print out a
receipt/ticket for evidence?? It's not difficult to do these days.
They could even include a .jpg of the target vehicle,with the data at the
bottom,like a date/time stamp.

Probably because few speeding tickets are successfully challenged in
court, but it would be an excellent idea.


Best regards,
Spehro Pefhany

 

[Rich Grise, Plainclothes Hippie]

You've got to read the classics more Rich. I believe a petard is either a
type of morter/cannon or similar to a satchel charge. (gee, maybe I should
read the classics more myself and find out)

Boy hippie to girl hippie: "Ever been picked up by the fuzz?"
"No, but I bet it really hurts."

Anybody else find it tiresome explaining jokes to the dull?

Thansk,
Rich

 

[Richard Henry]

Yes. However, at the speeds cars travel, the error generated is
less than a single MPH. If the targets were mach speed jets, the
error would be more than negligible. With this scenario, it is 100%
negligible.

My question was rhetorical, and your answer shows you don't know what
you are talking about.

 

[[email protected]]

Perhaps you should **** off.


This has nothing to do with fire control, you retarded twit.

All of this pulsed doppler radar technology stems from the radars
designed to shoot down airplanes (in WWII) and the process is called
"fire control'
The rest of your profane rant only demonstrates how little you know

To say you can get an accurate doppler shift from a target that is
shot from the side is an example. All radar can do is indicate rate of
closure or departure. When it is at 90 degrees from the direction of
travel that rate is exactly ZERO. It will then increase as the cosine
of range and speed as the angle decreases

 

[jasen]

I once heard -- what's probably an urban legend -- that in some state the
penalties for speeding were tabulated, e.g., 0-4MPH, $xx, 5-10MPH, $yy, etc.,
but that it stopped at something like 50MPH over so technically it you went,
e.g., 120MPH you weren't breaking any laws.



Of course, in reality, even if that part could be shown in court, you'd still
be ticketed for reckless driving!

if your laywer could sucessfully argue that the speed you were doing was safe
you could escape that one without paying. (such happened in Australia)


Bye.
Jasen