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Do antennas radiate photons?
“The antenna, like the eye, is a transformation device converting
electromagnetic photons into circuit currents; but, unlike the eye, the antenna can also convert energy from a circuit into photons radiated into space. In simplest terms an antenna converts photons to currents or vice versa.” Antennas, Second Edition, 1988, by John D. Kraus. Page 19. |
Do antennas radiate photons?
On 7/11/2015 11:33 AM, Wayne wrote:
“The antenna, like the eye, is a transformation device converting electromagnetic photons into circuit currents; but, unlike the eye, the antenna can also convert energy from a circuit into photons radiated into space. In simplest terms an antenna converts photons to currents or vice versa.” Antennas, Second Edition, 1988, by John D. Kraus. Page 19. What about it? Is there some reason why RF photons should not exist? -- Rick |
Do antennas radiate photons?
rickman wrote:
On 7/11/2015 11:33 AM, Wayne wrote: “The antenna, like the eye, is a transformation device converting electromagnetic photons into circuit currents; but, unlike the eye, the antenna can also convert energy from a circuit into photons radiated into space. In simplest terms an antenna converts photons to currents or vice versa.” Antennas, Second Edition, 1988, by John D. Kraus. Page 19. What about it? Is there some reason why RF photons should not exist? There are a lot of people that believe that light is somehow special and the dual nature of all electromagnetic radiation doesn't exist. Most of them base this on the fact that it is impossible with current technology to detect a single photon at frequencies lower than light. -- Jim Pennino |
Do antennas radiate photons?
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Do antennas radiate photons?
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Do antennas radiate photons?
FBMBoomer wrote:
On 7/11/2015 1:04 PM, wrote: rickman wrote: On 7/11/2015 11:33 AM, Wayne wrote: “The antenna, like the eye, is a transformation device converting electromagnetic photons into circuit currents; but, unlike the eye, the antenna can also convert energy from a circuit into photons radiated into space. In simplest terms an antenna converts photons to currents or vice versa.” Antennas, Second Edition, 1988, by John D. Kraus. Page 19. What about it? Is there some reason why RF photons should not exist? There are a lot of people that believe that light is somehow special and the dual nature of all electromagnetic radiation doesn't exist. Most of them base this on the fact that it is impossible with current technology to detect a single photon at frequencies lower than light. Radiating RF at the same wavelength as light will produce an electromagnetic field that is not visible to any eye. Babble; light IS electromagnetic radiation. https://en.wikipedia.org/wiki/Light If you think that photons will be converted to electric current on an antenna, try flashing a light on any antenna and check for results. Babble; antennas for light frequencies have been contructed in labs and guess what, they produce a voltage. Research continues to make them a practical solar energy converter. http://arxiv.org/pdf/1204.0330v1.pdf https://en.wikipedia.org/wiki/Nantenna http://www.nature.com/nphoton/journa....2010.237.html Please report back any findings here. :-) I find you are an ignorant babbler. -- Jim Pennino |
Do antennas radiate photons?
On Sat, 11 Jul 2015 08:33:24 -0700, "Wayne"
wrote: The antenna, like the eye, is a transformation device converting electromagnetic photons into circuit currents; but, unlike the eye, the antenna can also convert energy from a circuit into photons radiated into space. In simplest terms an antenna converts photons to currents or vice versa. Antennas, Second Edition, 1988, by John D. Kraus. Page 19. Yep, antennas radiate photons. Quantum theory treats RF and light as both a wave and a particle. If you put a pressure gauge behind a flat plate in front of your antenna, you would be able to detect the tiny pressure produced by your RF emissions. The problem is that it's very very very small because the energy decreases linearly with the frequency. When calculating orbital mechanics, light pressure is a major consideration. When building interstellar space craft, "light sails" are a common idea. This should explain it: https://www.khanacademy.org/test-prep/mcat/physical-processes/light-and-electromagnetic-radiation-questions/v/photon-energy# Photon (RF or light) pressure have been measured in the laboratory by using two pressure gauges, blocking RF and light from one gauge, and measuring the differential pressure. The differential measurement cancels external influences, such as gravity, wind, earth movement, etc. In Kraus 3rd edition (2002), the term "photons" appears in questions 2-16-1. 2-16-1. Spaceship near moon. A spaceship at lunar distance from the earth transmits 2 GHz waves. If a power of 10 W is radiated isotropically, find (a) the average Poynting vector at the earth, (b) the rms electric field E at the earth and (c) the time it takes for the radio waves to travel from the spaceship to the earth. (Take the earth-moon distance as 380 Mm.) (d) How many photons per unit area per second fall on the earth from the spaceship transmitter? I couldn't paste the answer because the original, in MS Word format, used characters in the formulas that don't translate to ASCII very gracefully. I'll try to trasnscribble and annotate for clarity: (d) Energy_of_Photon = hf = 6.63*10^-34 * 2*10^-24 J where h=6.63*10^-34 Js (Plank's constant) This is the energy of a 2.5 MHz photon. From (a), PV=5.5*^10-18 Js^-1 m^-2 Therefore, number of photons = (5.5*10^-18 / 1.3*^10^-24) = 4.2*10^6 m^-2 s^-1 (or 1/J) -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
Do antennas radiate photons?
On Sun, 12 Jul 2015 19:54:44 -0700, Jeff Liebermann
wrote: Oops. I goofed in typing in several places. The last part should be: (d) Energy_of_Photon = hf = 6.63*10^-34 * 2*10^9 J = 1.3*10^-24 J where h=6.63*10^-34 Js (Plank's constant) This is the energy of a 2.5 MHz photon. From (a), PV=5.5*10-^18 Js^-1 m^-2 Therefore, number of photons = (5.5*10^-18 / 1.3*^10^-24) = 4.2*10^6 m^-2 s^-1 Hmm... I have no idea where the "2.5 MHz" came from or the strange units for the "number of photons". -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
Do antennas radiate photons?
In article , Jeff Liebermann writes:
Photon (RF or light) pressure have been measured in the laboratory by using two pressure gauges, blocking RF and light from one gauge, and measuring the differential pressure. The differential measurement cancels external influences, such as gravity, wind, earth movement, etc. Maxwell's equations - classical field theory - predict light pressure even without photons and quantum theory. Double slit experiments show interference patterns are followed even by single photons allowed to to pass - exactly as if each photon converted to a wave and portions passed through each slit and thus _the photon interfered with itself_. You really have to observe quantum effects before you can register individual photons. And, with e = h nu, nu being frequency, quantum effects at UHF and below are much harder to see because each photon has such low energy. George |
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