What “is” a radio signal-?

Discussion in 'Science and Technology' started by watchingfromafar, Aug 25, 2018.

  1. DOTR
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    DOTR Gold Member

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    Sorry but a photon has no mass.
     
  2. toobfreak
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    toobfreak Gold Member

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    Put simply, "radio" waves are the lowest bottom portion of the electromagnetic spectrum originally postulated by Maxwell in the 19th century as "Hertzian" waves. They are commonly generated by many astronomical bodies in space and are convenient to us here because their wavelengths lend themselves to easy (low energy) generation that can be bounced off the ionosphere around the earth, they can penetrate the atmosphere from space for communication, they couple to the Earth in a way so as to enable them to go around bends and over hills, and at low enough frequencies can even penetrate the ocean to allow communication with subs far out to sea and deep under water, which makes them very practical and useful to us.

    Like all EM phenomena, they are merely a radiating wavefront of alternating electric potential. As the electric field crosses a conductor, its magnetic component induces a current to flow in it which is analogous to the originating signal, hence "wireless" communication.

    "Radio" then is merely the simple process of using the radio wave as a higher frequency "carrier" of "intelligence" (signal), by simply modulating the carrier with an audio (AM/FM) or television/video, etc., signal. Received by a circuit tuned to resonate (be sensitive to) the desired frequency, it is then a fairly simple process to strip the intelligence off the carrier via a "detector" circuit, then down convert and amplify it to usable (audible or visible) levels. Voila. Radio communication. You are now an expert.

    BTW, Nikola Tesla and not Marconi, was the original inventor of radio communication.
     
  3. watchingfromafar
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    watchingfromafar Silver Member

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    Ok, after further research I find your statement correct.

    What is the mass of a photon?
    This question falls into two parts:
    Does the photon have mass? After all, it has energy and energy is equivalent to mass.
    Photons are traditionally said to be massless.
    This is a figure In classical electromagnetic theory, light turns out to have energy E and momentum p, and these happen to be related by E = pc. Quantum mechanics introduces the idea that light can be viewed as a collection of "particles": photons. Even though these photons cannot be brought to rest, and so the idea of rest mass doesn't really apply to them, we can certainly bring these "particles" of light into the fold of equation (1) by just considering them to have no rest mass. That way, equation (1) gives the correct expression for light, E = pc, and no harm has been done. Equation (1) is now able to be applied to particles of matterand "particles" of light. It can now be used as a fully general equation, and that makes it very useful.

    Is there any experimental evidence that the photon has zero rest mass?
    Alternative theories of the photon include a term that behaves like a mass, and this gives rise to the very advanced idea of a "massive photon". If the rest mass of the photon were non-zero, the theory of quantum electrodynamics would be "in trouble" primarily through loss of gauge invariance, which would make it non-renormalisable; also, charge conservation would no longer be absolutely guaranteed, as it is if photons have zero rest mass. But regardless of what any theory might predict, it is still necessary to check this prediction by doing an experiment.

    It is almost certainly impossible to do any experiment that would establish the photon rest mass to be exactly zero. The best we can hope to do is place limits on it. A non-zero rest mass would introduce a small damping factor in the inverse square Coulomb law of electrostatic forces. That means the electrostatic force would be weaker over very large distances.
    What is the mass of a photon?

    Ok, this still does not tell me "what" a radio wave "IS"
     
  4. toobfreak
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    toobfreak Gold Member

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    We are quickly getting far astray of laymen terms, but the "photon" is merely the force carrier as a unit of "quanta" with a particular charge, spin, and energy state which conveys the charged lepton component (no strong interaction) that combined with certain quarks (strong interaction), combine to form 1st generational Hadrons (ordinary matter). At high enough energies, the photon conveys the electromagnetic wavelengths of visible light (and beyond). At low enough energies, it conveys the electric field of a radio wave.
     
  5. watchingfromafar
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    watchingfromafar Silver Member

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    I think I found my own answer.
    Electromagnetic radiation is transmitted in waves or particles at different wavelengths and frequencies. This broad range of wavelengths is known as the electromagnetic (EM) spectrum. The spectrum is generally divided into seven regions in order of decreasing wavelength and increasing energy and frequency. The common designations are radio waves, microwaves, infrared (IR), visible light, ultraviolet (UV), X-rays and gamma-rays.

    Radio waves have the longest wavelengths in the EM spectrum, according to NASA, ranging from about 1 millimeter (0.04 inches) to more than 100 kilometers (62 miles). They also have the lowest frequencies, from about 3,000 cycles per second or 3 kilohertz (kHz) up to about 300 billion hertz, or 300 gigahertz (GHz).


    What Are Radio Waves?

    A radio wave consists of "particles" that have no measurable mass. Hence, they exists only in the trail they leave behind.

    Or so it seems
     
  6. toobfreak
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    toobfreak Gold Member

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    Why?

    You're a jackass. This whole thread is a rib, right?
     
  7. watchingfromafar
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    watchingfromafar Silver Member

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    Ok, now I am even more lost than before.

    What is an atom?

    An atom a fundamental piece of matter. (Matter is anything that can be touched physically.) Everything in the universe (except energy) is made of matter, and, so, everything in the universe is made of atoms.
    An atom itself is made up of three tiny kinds of particles called subatomic particles: protons, neutrons, and electrons. The protons and the neutrons make up the center of the atom called the nucleus and the electrons fly around above the nucleus in a small cloud. The electrons carry a negative charge and the protons carry a positive charge. In a normal (neutral) atom the number of protons and the number of electrons are equal. Often, but not always, the number of neutrons is the same, too.

    What is an atom?
     
  8. watchingfromafar
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    watchingfromafar Silver Member

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    I did not state the post, I just posted what others have said.

    In your own words; You're a jackass.
     
  9. Crepitus
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    Crepitus Gold Member

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    It does have mass. It's made up of photons. Also they are electrically neutral.
     
  10. Checkerboard Strangler
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    Checkerboard Strangler BANNED

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    "We are the Joy Boys of radio, we chase electrons to and fro."

    That's radio, electrons vibrating at a frequency high enough that they are able to "radiate" off of a tuned antenna element and cause neighboring electrons to vibrate along with them at a certain voltage. (RF energy) (the RF equivalent of a tuning fork)

    Tuned antenna elements in proximity will resonate and the resulting current is detected in a tuned tank circuit, which is the RF equivalent of a tuning fork or tuned wine goblet.

    TANK CIRCUIT

    That's vastly oversimplified of course.
     
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