The only law enforcement agency in Pennsylvania that is allowed to operate police radar guns is the State Police and only when in stationary mode.

State procurement records over the past 5-years indicate that the following police radar guns are used by both state and local police agencies.

Decatur Genesis K-band
Kustom Signals Falcon HR K-band
Kustom Signals KR10 K-band

The radar gun the officer is holding is a Decatur Genesis K-band.
 


There is a power cord running from the bottom of the gun to a cigarette lighter adapter plug within the car. You cannot see much of it because it is hidden behind the officer's hand.

The multi-part Kustom Signals KR10, shown below, consists of a dash-mounted radar measuring unit with an emitter that gets mounted somehow on the outside of the squad car, or perhaps placed on the dash next to the measuring unit.  There's also a button the officer pushes to turn the radar on and off.  

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Google+ was an Internet-based social network owned and operated by Google. The network was launched on June 28, 2011 in the attempt to challenge other social networks and for a time linked other Google products like Blogger and YouTube. The service, Google's fourth foray into social networking, experienced strong growth in its initial years, although usage statistics varied, depending on how the service was defined. Three Google executives oversaw the service, which underwent substantial changes that led to a redesign in November 2015.

Due to low user engagement and disclosed software design flaws that potentially allowed outside developers access to personal information of its users,^[4] the Google+ developer API was discontinued on March 7, 2019 and Google+ was shut down for business use and consumers on April 2, 2019.

First note that h=6.63x10^-34 joule-sec, then the energy of ONE photon is almost 0 (the actual value at 1 Hz is 6.62606957 × 10^−34 joules, which is the reason a radar signal needs zillions of photons to even get a few photons back to the receiver.

The article is poorly written (for instance n is not defined 

Since the photon energy, E, is equal to hn, where h = Planck's constant = 6.63 X 10^-34 j sec, then

E = h

One thing to note is that it never claims the photon is received at a speed of c+v, unlike Ed's claim. At least they got that right.

It seems to be part of some dumbed down 'science & math for kids or laymen' set.

Consider a single photon from the police radar. The photon must interact with the approaching car for a finite time while it is being reflected. Call this time, t. Let an interaction force, ± f, exist between the photon and the car for the time, t. The force exerted by the photon on the car, +f, acts to remove energy from the car. The force exerted by the car on the photon, -f, acts to add energy to the photon. Therefore, we expect the photon frequency to increase.

When a photon is emitted from a police radar gun, the photon will interact with an atom in the approaching car for a period of time while the photon is being reflected.  Call this "reaction time."  During the reaction time, the photon will exert a force upon the atom.  The force is positive if the car is approaching, and it is negative if the car is moving away from the radar gun.  Therefore we can expect the return photon's oscillation frequency to increase if energy is added to the photon.   

I shouldn’t have been so surprised when things started escalating. I mean, I knew people hated me. It was a real thing. Being recognized by fans is very different from checking out at the corner store and not knowing if the clerk is a Defender thinking about what a dirty traitor you are. I thought that I could only either run away from that or fight it, so I fought it. Fear is an even better fuel than anger. Also, it is even more destructive. Their constant attacks meant I never had to doubt my message. It must be right, because the people who disagreed with me were sooooo awful.

A friend of mine once told me that, no matter how much you proofread, the first time you open the final version of your book, you will find a typo on the very first page you look at. Ugh.

That article describes electromagnetic radiation as being EITHER a wave OR a photon.  It doesn't decide one way or the other.

Why do you think a decision is required?

Because SCIENCE is about how things work.  You are saying we do not KNOW how light works, except that it sometimes acts like a particle and it sometimes acts like a wave.  That is not science, it is an admission of IGNORANCE.

Wrong. It is an acknowledgement that light is neither a true wave nor true particles.  It has properties of both, but is not either one.

First we are not talking about "SCIENCE" but about "Radar Guns". All radars, including radar guns, are electronic devices designed and built by electrical engineers (see https://en.wikipedia.org/wiki/Radar). They have worked quite well and accurate for over 80 years using the good old (and currently still used) classical wave model (Classical Electrodynamics).

Humans, like you or me, are unable to answer questions like "how light works".  The reason is quite simple: we are only capable of processing thoughts, which physicists (like Einstein) use to formulate MODELS which try to approximate the way Nature does whatever it does.

A physical MODEL like Classical Mechanics, Classical Electrodynamics, Special Relativity, General Relativity, Quantum Mechanics, Quantum Electrodynamics, etc. represent achievements of our human intellect, but none of them answer "HOW AND WHY NATURE DOES WHAT IT DOES".

The continuous wave (CW) radar is frequently used for detection and tracking of moving targets. In its simplest form a single sinusoid is transmitted, and the received signals are mixed with the transmitted carrier frequency. The existence of moving targets is determined from the beat note or Doppler frequency shift f_d . 

 

     Our democracy cannot survive its current downward drift into tribalism, extremism, and seething resentment. Today it’s “us versus them” in America. Politics is little more than blood sport. As a result, our willingness to believe the worst about everyone outside our own bubble is growing, and our ability to solve problems and seize opportunities is shrinking.
     We have to do better. We have honest differences. We need vigorous debates. Healthy skepticism is good. It saves us from being too naive or too cynical. But it is impossible to preserve democracy when the well of trust runs completely dry.

Digital radar guns measure speed based on a 12-inch travel distance of target vehicles, compared to 10 to 15 car lengths used by analog guns.

Older, analog radar guns always display the strongest reflected signal. This creates great frustration when you are locked on to an approaching 18-wheeler in a group of oncoming vehicles that includes a speed demon sports car. You see the Mustang going 80 mph, but the radar gun shows 53 mph because it's reading the 18-wheeler.

The best way to understand how radar guns work is to just follow one single photon to the target and back.

I want to emphasize that light comes in this form - particles. It is very important to know that light behaves like particles, especially for those of you who have gone to school, where you were probably told something about light behaving like waves.  I'm telling you the way it does behave - like particles.  

The 'constant speed of light' postulate predicts that two inertial observers – for instance twins in spaceships free-floating in outer space – will each see the other's clock running slower than his own.

Ed, imagine you're in a space ship, in outer space. 
Looking through the front window, you spot an
approaching asteroid.  You aim the radar gun at it:

I)  You are stationary, the asteroid is moving
    toward you at 90 mph.  What does the device read? 
    Will a patrol cop cite you for speeding?

II) The asteroid is stationary, you are moving
   forward at 90 mph.  What does the device read? 
   Will a patrol cop cite you for speeding?

Those situations are FANTASY situations that mathematicians use to argue that all motion is relative.  

Einstein said that the speed of light is always emitted at c and cannot
exceed c.

Your FANTASY situations have my spaceship and the asteroid in empty space with no frames of reference to determine who is moving. In reality, of course, both are moving.  The only question is: who is moving fastest?  That is determined by finding out who is moving closer to the fixed speed of light.  

According to my paper, I should be able to point my radar gun at the wall inside my space ship to determine my speed relative to the speed of light. The gun subtracts my speed v from the speed of light c to show my speed.

Knowing my speed, I can then point the gun at the asteroid and get its
speed relative to the speed of light.  If it is moving at 90 mph, the
gun will read 90 mph, but won't say whether it is positive or negative.

If the asteroid is stationary relative to me, then we are both moving in
the same direction.  If the asteroid is moving relative to me, then the
asteroid is moving at 90 mph in a different direction than I am.

If the asteroid is moving at 200 mph relative to the speed of light,
the gun will show that.  That has no effect on how fast I am moving.

I should probably have spent some time thinking about what I just wrote, but I think it is correct.

"The unsuccessful attempts to discover any motion of the Earth relative to the 'light medium' suggest that the phenomena of electrodynamics, as well as those of mechanics, possess no properties corresponding to an absolute rest ^a9. But rather that the same laws of electrodynamics are valid for all frames of reference for which the equations of mechanics hold good ^b10. We will raise this conjecture to the status of a 'relativity postulate'. And will introduce another, only apparently irreconcilable with the former, namely that light is always propagated in empty space with a definite velocity c, independent of the state of motion of the emitting body. The introduction of a 'luminiferous aether' will thus prove superfluous."¹¹

He later amplified the last bit to:

"Light in vacuo has a definite velocity of propagation, independent of the state of motion of the source or of the observer."¹² (italics ours)

The second principle, on which the special theory of relativity rests, is the "principle of the constant velocity of light in vacuo." This principle asserts that light in vacuo always has a definite velocity of propagation (independent of the state of motion of the observer or of the source of the light).

Einstein's Special Relativity is based on two fundamental assumptions, the so-called 'Einstein postulates'. The 'constant speed of light' postulate predicts that two inertial observers – for instance twins in spaceships free-floating in outer space – will each see the other's clock running slower than his own. The 'relativity' postulate says that both perceptions are equally valid, effectively correct. The logical incoherence of this makes a nonsense of the postulates, and by extension of Special Relativity itself.

The 'constant speed of light' postulate predicts that two inertial observers – for instance twins in spaceships free-floating in outer space – will each see the other's clock running slower than his own.

The radar gun above has a larger button than the Bushnell gun in the image below, plus the image below shows a very clear vertical gap between the left and right sides that does not show up on the above image no matter how much I enlarge it or clarify it.
  

Why police would have a Bushnell Speedster in their car is a mystery.  It cannot be used in court.  They used it in the video to show the speed of the police car, so it was likely pointed at the highway instead of the white car.  Groan.  I really really need to figure how how perform or have someone else perform my radar gun experiment.

May 28, 2019 - When I turned on my computer this morning, my inbox contained an email from a Japanese author who wanted permission to use a couple photographs I took in Misawa, Japan, in 1964 in a book he is translating from English to Japanese.  The book is titled "62 Years on the Hill."  I'd never heard of the book before, but it looks interesting.  Too bad my library doesn't have a copy. 

I gave the guy the permission he asked for.  He evidently found the pictures on my blog page about "Google Street View Time Travel."

Yesterday, I got bogged down on digging through web pages looking for details about specific makes and models of radar guns.  So, to clear my mind, I turned off my computer, sat down in a chair in the living room and listened to the audio book version of Arthur C. Clarke's sci-fi novel "3001: The Final Odyssey."

 'Almost the whole of the technology we take for granted was invented near the very end of our Millennium - the steam engine, electricity, telephones, radio, television, cinema, aviation, electronics. And, during a single lifetime, nuclear energy and space travel - what would the greatest minds of the past have made of these? How long could an Archimedes or a Leonardo have retained his sanity, if suddenly dumped into our world?'

Today, of course, it seems ludicrous that we could have imagined giant space-stations, orbiting Hilton Hotels, and expeditions to Jupiter as early as 2001. It is now difficult to realize that back in the 1960s there were serious plans for permanent Moon bases and Mars landings - by 1990!

Q. Will my radar work while my vehicle is moving?

A. No, the GHD and SCOUT radar guns are a stationary only models, so your vehicle should be parked. You need to hold the radar steady while operating it.

Question: If in a moving vehicle, can the Bushnell Speedster pick up the speed of another moving object?

Answer:  No. However, if you would like to know the speed of the vehicle you are in, point the Speedster at a stationary object, such as the ground.

     After a while, I saw that I was having trouble talking with them whenever I thought I knew more than I really did about their work. I was boxing in the scientists with questions that were based on false assumptions. I took a bold step and stopped reading the scientists’ research papers before I met with them. I would come in armed only with curiosity and my own natural ignorance. I was learning the value of bringing my ignorance to the surface. The scientists could see exactly how much I already understood, and they could start there.
     Ignorance was my ally as long as it was backed up by curiosity. Ignorance without curiosity is not so good, but with curiosity it was the clear water through which I could see the coins at the bottom of the fountain.
     It led to a dynamic relationship. The scientists were glad to see that I really wanted to understand their work, and, just as it does in improv games, it had an effect on them and they themselves became more responsive. They could relate to me as a person.

     For the last twenty years, I’ve been trying to understand why communicating seems so hard—especially when we’re trying to communicate something weighty and complicated. I started with how scientists explain their work to the public: I helped found the Center for Communicating Science at Stony Brook University in New York, and we’ve spread what we learned to universities and medical schools across the country and overseas.
     But as we helped scientists be clear to the rest of us, I realized we were teaching something so fundamental to communication that it affects not just how scientists communicate, but the way all of us relate to one another.

In 2014, he [Alan Alda] was named a fellow of the American Physical Society for his work in helping scientists improve their communication skills. He is a member of the board of the World Science Festival and is a Visiting Professor at Stony Brook University’s Alan Alda Center for Communicating Science.

     Ike Antkare is the name of a fake scientist created by the French researcher Cyril Labbé, who wanted to see if a mere golem like Antkare could make a name for himself on the Internet among real scientists.
     He certainly could. Labbé used a computer program called SCIgen (created by graduate students at MIT) to generate dozens of fake papers using just a few keystrokes. In a short time, the fictional Ike Antkare had so many citations, he became, according to Labbé, “one of the great stars in the scientific firmament.” This happened mainly because the fake papers were picked up by Google Scholar, which is used by other organizations to rate authors on how many times they’ve been cited. After Labbé was finished gaming the system, Google Scholar ranked Ike Antkare number twenty-one on the list of most cited authors. Ike didn’t have as many citations as Sigmund Freud, but he had more than Albert Einstein.
     The golem ruled.
     Labbé went further. He developed a program that could detect whether a paper had been created using SCIgen. He found 120 papers that had been accepted and published by peer-reviewed journals—all created by SCIgen and all fakes.

In an instant, Earth is carved up and reassembled like a huge jigsaw puzzle. Suddenly the planet and every living thing on it no longer exist in a single timeline. Instead, the world becomes a patchwork of eras, from prehistory to 2037, each with its own indigenous inhabitants.

It’s hard for us to imagine today, but no spaces separated the words in early writing. In the books inked by scribes, words ran together without any break across every line on every page, in what’s now referred to as scriptura continua. The lack of word separation reflected language’s origins in speech. When we talk, we don’t insert pauses between each word—long stretches of syllables flow unbroken from our lips. It would never have crossed the minds of the first writers to put blank spaces between words. They were simply transcribing speech, writing what their ears told them to write.

Text messaging now represents one of the most common uses of computers, particularly for the young. By the beginning of 2009, the average American cell phone user was sending or receiving nearly 400 texts a month, more than a fourfold increase from 2006. The average American teen was sending or receiving a mind-boggling 2,272 texts a month. Worldwide, well over two trillion text messages zip between mobile phones every year, far outstripping the number of voice calls.   

On the web page http://vixra.org/abs/1806.0027 the author tell's how he is now trying to learn what he in was in this article trying to teach. See, e.g., the comment with the date "May 6, 2019".

The article quotes "A radar gun in a car traveling down the highway at 60 MPH will measure a tree to have a speed of 60 MPH." and claims that "that answer is in disagreement with fundamental physics". However, the quoted statement is true in the sense that anyone who has a radar gun (the abstract says they are inexpensive) can try and see that that indeed is what happens. If "fundamental physics" says otherwise then "fundamental physics" is wrong. 

I hope you can fax this book to us in your next transmission - we're all anxious to read it.

Radar and laser guns don’t work well through tinted glass, which is why officers typically use them outside the vehicle or with the windows down.

even the police car’s own heater or air conditioner fan can cause enough mechanical interference to cause a radar gun to register a stationary rock at 70 mph or a palm tree at 28 mph.

Mechanical Interference is any moving object, other than the target vehicle, that can produce a false or incorrect radar reading. The most common sources are vibrating or rotating signs near the roadway; fan blades moving inside or outside the patrol car (air conditioner, heater, defroster or engine fan); another moving vehicle that reflects radar waves better than the target vehicle; and multiple targets in the main radar beam causing multiple reflections of nearly equal strength and making the display read, high, low, or completely blank. 

Question: How does the Speedster work?

Answer: Once the trigger is engaged, the Speedster transmits radio frequency energy in the form of waves. The radar transmits 24 billion RF cycles of energy per second at the speed of light, which is 186,000 miles per second. The Speedster measures the difference between transmit and receive signals and relays this information to the DSP to quickly calculate +/- one MPH speed accuracy.  

Question: If in a moving vehicle, can the Bushnell Speedster pick up the speed of another moving object?

Answer:  No. However, if you would like to know the speed of the vehicle you are in, point the Speedster at a stationary object, such as the ground.

Question: What is unique about the Speedster compared to other radar guns?

Answer: The Speedster uses advanced Digital Signal Processing (DSP) software to filter out bad information, providing valid accurate information. In addition, the Speedster is capable of tracking baseball statistics.

Question: What technology does the Speedster consist of?

Answer: The Bushnell Speedster contains a K-Band microwave RF (Radio Frequency) transmitter whose signal gets reflected by the target object. The reflected signal will have a "Doppler Shift" proportional to the target speed. This Doppler frequency shift is detected in the receiver, amplified, filtered, and then digitized in an Analog to Digital Converter (ADC), and passed onto the Digital Signal Processing (DSP) chip. Using complex algorithms, the DSP chip filters out false and low level return signals, to identify and display the speed of the desired target. The speed along with various statistics and averages are then displayed on the LCD display.

Question: Can the Bushnell Speedster track arrow speed?

Answer: No.

Question: Can the Bushnell Speedster track club head speed?

Answer: No.

 In "Small Town" a man creates a perfect scale model of his own town, as a means of escaping his unbearable reality. In "Human Is" the wife of a scientist notices that her husband has returned from a scientific expedition a changed man, but she's not complaining. In "Foster, You're Dead" a father's unwillingness to participate in his country's preparations for a war that never happens, leads to unexpected consequences for his family. In "The Hanging Stranger" a man is unable to convince his fellow townspeople that something terribly wrong is happening to them all. Finally, in "A World of Talent", society's reactions against those who have unusual talents have pushed the situation to the brink of interplanetary war.     

Incidentally, people sometimes mistakenly think that the tuning fork calibration works by putting the fork arms in motion at the calibration speed. It should be obvious that this is not correct, first because the arms of a tuning fork move at a range of speeds, positive and negative, on each cycle, second because the speed of motion differs along the length of the arms, and third because the maximum speed of the arms depends not just on the frequency but on the amplitude, which depends on how the tuning fork is struck. It would generate a specific maximum speed of arm movement only if struck with precisely the right force, and even then it would begin to dampen out immediately, so it would actually produce a continuously varying maximum speed, which would be different at different positions on the arm, and with different orientations. Hence the arms of a tuning fork obviously do not move at a consistent reference speed.

would generate a specific maximum speed of arm movement only if struck with precisely the right force, and even then it would begin to dampen out immediately, so it would actually produce a continuously varying maximum speed

It’s important to note that the tuning fork is not sending a signal of 30 GHz + 4480 Hz, as would be the case for a genuine speed detection for 50 mph. The arm of the tuning fork is never moving at 50 mph (not even close). The tuning fork is only modulating the incident signal (which merely serves as a carrier wave), and this modulation has a frequency of 4480 Hz, which is equal to the beat frequency that would result from a Doppler-shifted signal reflected off an object approaching at 50 mph. In effect, the tuning fork is tricking the radar gun into thinking there is an object approaching at 50 mph, when in fact the tuning fork is just inducing a fluctuation in the antenna and receiver at the frequency of the beat that would be produced by an object approaching at 50 mph.

Hence the arms of a tuning fork obviously do not move at a consistent reference speed. Moreover, to produce a maximum arm speed of 50 mph at the relevant frequency of (say) 4480 Hz would require the arm to swing a distance of 78 mm, whereas a typical tuning fork of this size has a maximum arm displacement of only about 0.02 mm. So, the speed of the arms of a tuning fork is orders of magnitude less than the speed of a moving automobile. For all these reasons, it is obvious that tuning forks do not (and could not) test radar guns by producing a moving surface at the calibration speed. 

The velocity of a wave is proportional to its frequency. Doppler effect shows that both the velocity and the frequency depend on the reference frame. The higher the detected frequency is, the faster the wave travels toward the detector. One example is the radar gun used by the traffic police. The reflected radio wave travels faster than the emitted radio wave. This results in frequency difference between two waves. This difference is used to calculate the velocity of a vehicle.

 

He survived riots, revolutions, civil wars, trigger-happy child soldiers, voodoo priests, jihadists, robbers, corrupt cops, and Cape buffalo. He traveled through every kind of earthquake, cyclone, tsunami, volcanic eruption, snowstorm, and sandstorm that nature threw at him. He ate everything from old camel meat and African field rats to dung beetles and the brain of a live monkey. And he overcame encounters with crocodiles, hippos, anacondas, giant leeches, flying crabs―and several beautiful women who insisted that he stop this nonsense and marry them.

"At 26 square miles, it is the third smallest nation, larger only than Monaco (0.7 square miles) and Vatican City (0.2 square miles). With fewer than 10,000 inhabitants, Nauru is ahead of only Vatican City (population 850), the smallest internationally recognized independent state by both area and inhabitants."      

Incidentally, people sometimes mistakenly think that the tuning fork calibration works by putting the fork arms in motion at the calibration speed. It should be obvious that this is not correct, because the speed of the arms of a tuning fork depends not just on the frequency but on the amplitude, which depends on how hard we strike it.  It would generate a specific speed of arm movement only if struck with precisely the right force, and even then it would begin to dampen out immediately, so it would actually produce a continuously varying maximum speed, making it not useful for calibration. Moreover, to produce an arm speed of 50 mph at the relevant frequency of (say) 4480 Hz would require the arm to swing a distance of 78 mm, whereas a typical tuning fork of this size has a maximum arm displacement of only about 0.02 mm. So, tuning forks do not test radar guns by producing a moving surface at the calibration speed.  Needless to say, they also do not work by means of acoustic sound waves, since the radar receiver isn’t affected by acoustic waves.  It just so happens that the Doppler shift for automobile speeds and radar waves is in the range of audible frequencies.

There are 2 basic qualities of sound:

• Pitch (high & low)
• Volume (loud & soft)

Pitch is related to frequency. Changing the number of vibrations per second changes the pitch. The pitch that a particular tuning fork generates depends on the length of its prongs. Each fork is stamped with the note it produces (e.g. A) and its frequency in Hertz (e.g. 440 Hz). Shorter prongs produce higher pitch (frequency) sounds than longer prongs. Long prongs will bend more readily and therefore tend to vibrate at a lower frequency when struck.

Volume, or loudness, is related to the strength, intensity, pressure, or power of the sound. Bigger/ amplified vibrations result in bigger/louder sounds.

Dijksterhuis’s work also shows that our unconscious thought processes don’t engage with a problem until we’ve clearly and consciously defined the problem. If we don’t have a particular intellectual goal in mind, Dijksterhuis writes, “unconscious thought does not occur.”

1. Can a radar gun send and receive signals at the same time?

2. Can a radar gun measure distances?

As opposed to pulsed radar systems, continuous wave (CW) radar systems emit electromagnetic radiation at all  times. Conventional CW radar cannot measure range [i.e., distance] because there is no basis for the measurement of the time delay. Recall that the basic radar system created pulses and used the time interval between transmission and reception to determine the target's range.  If the energy is transmitted continuously then this will not be possible. 

Lasers use light and we know the speed of light (roughly 186,000 miles per second). When we send a quick pulse of light out, it will travel from the lidar gun, to the target vehicle, and back. If we measure how much time it takes to get a reflection (time of flight), we can calculate how far the light had to travel. Because the laser beam had to make a round trip to the car and back, if we divide that number by two, we’ll get the distance between the lidar gun and the target vehicle. That’s step one.

Now one pulse will give us distance (not speed), but if we shoot a whole series of pulses, we can determine the change in distance over time which will tell us the vehicle’s speed. (Speed is simply a measure of distance divided by time, i.e., feet/second or miles/hour).

Laser guns typically take about 0.3 sec to get a lock on a vehicle and for an example laser gun that fires 200 pulses per second, this means it needs 60 return pulses to get a reading.

As a vehicle moves towards or away from the gun, the distances should all make sense… something like 1000 feet, 999, 998, 997, 996, and so on. It’s only with a smooth set of distances like this that the gun can ensure that it’s locked onto a single target, it has a clean lock, and so on.

There seems to be a widespread misconception (in some venues) that LIDAR speed guns do not use the Doppler effect to measure speed. This may be traced to a popular online source, which gives the following ‘explanation’ for how a LIDAR speed gun measures speed, contrasting it with how a radar gun measures speed:

A normal radar set sends out a radio pulse and waits for the reflection. Then it measures the Doppler shift in the signal and uses the shift to determine the speed.  Laser (or LIDAR, for light detection and ranging) speed guns use a more direct method that relies on the reflection time of light rather than Doppler shift.

This ‘explanation’ actually highlights two misconceptions.  First, it is obviously wrong to suggest that LIDAR speed guns don’t rely on the Doppler effect to determine speeds.