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#11
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Do antennas radiate photons?
"Jeff Liebermann" wrote in message ... Yep, antennas radiate photons. +1 There is not any proof that RF behaves differently than light. Things are already quite complicated without it :-) |
#12
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Do antennas radiate photons?
On Mon, 13 Jul 2015 13:45:43 +0200, "bilou" wrote:
"Jeff Liebermann" wrote in message .. . Yep, antennas radiate photons. +1 There is not any proof that RF behaves differently than light. Things are already quite complicated without it :-) One of my not so great ideas was to devise a contraption that would let me "see" RF. It certainly would make troubleshooting RF devices much easier. Essentially, it would be a human eye analog implimented with RF components. According to theory, if it works for light, it should also work for RF. At the time, I was working at about 1GHz. Light is about 400 THz. So, all I need is an eyeball that's 400,000 times larger than the human eye. I'll give myself a -1 for the idea. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#13
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Do antennas radiate photons?
"Jeff Liebermann" wrote in message ... On Mon, 13 Jul 2015 13:45:43 +0200, "bilou" wrote: "Jeff Liebermann" wrote in message . .. Yep, antennas radiate photons. +1 There is not any proof that RF behaves differently than light. Things are already quite complicated without it :-) One of my not so great ideas was to devise a contraption that would let me "see" RF. It certainly would make troubleshooting RF devices much easier. Essentially, it would be a human eye analog implimented with RF components. According to theory, if it works for light, it should also work for RF. At the time, I was working at about 1GHz. Light is about 400 THz. So, all I need is an eyeball that's 400,000 times larger than the human eye. I'll give myself a -1 for the idea. Wouldn't such a gadget be awesome for adjusting antennas! |
#15
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Do antennas radiate photons?
FBMBoomer wrote:
On 7/12/2015 7:31 PM, wrote: 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. Of course they produce a voltage. They do not produce light. You just said "try flashing a light on any antenna and check for results", idiot. Obviously shining a light on an antenna designed for MHz frequencies will not produce an electric current, but shining a light on an antenna designed for THz frequencies will. 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. Yet still, you have not tried your flashlight on any type of antenna to produce a signal. Try harder. I don't have the lab required to build a THz antennn, idiot. Again, for those who understand physics here, a very short wavelength electrical signal sent to an a tuned antenna at the frequency of say red light will produce zero light. It will produce electromagnetic radiation. They are not the same. Shining electromagnetic radiation on an antenna of the appropriate frequency does not produce electromagenetic radiation, it produces an electrical current, idiot. If you are so sure, just prove us all wrong and win the Nobel Prize in physics. I already gave you three links on the subject, idiot. -- Jim Pennino |
#16
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Do antennas radiate photons?
FBMBoomer wrote:
snip Again, for those who understand physics here, a very short wavelength electrical signal sent to an a tuned antenna at the frequency of say red light will produce zero light. It will produce electromagnetic radiation. They are not the same. If you can prove they are different then you will be the one in line for a Noblel prize. If you are so sure, just prove us all wrong and win the Nobel Prize in physics. At least one Nobel prize has already been awarded for parts of that proof. (AMI, how many of you are there?) -- Roger Hayter |
#17
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Do antennas radiate photons?
"Jeff Liebermann" wrote in message ... One of my not so great ideas was to devise a contraption that would let me "see" RF. It certainly would make troubleshooting RF devices much easier. Essentially, it would be a human eye analog implimented with RF components. According to theory, if it works for light, it should also work for RF. At the time, I was working at about 1GHz. Light is about 400 THz. So, all I need is an eyeball that's 400,000 times larger than the human eye. I'll give myself a -1 for the idea. Yes it is a question of scale. There is the trick to use a fluorescent light bulb close to an aerial. Energy saving lamps can be quite small . Puting the glass part of one in a microwave oven can be instructive. Don't forget the cup of water. :-) |
#18
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Do antennas radiate photons?
On Mon, 13 Jul 2015 08:33:34 -0700, "Wayne"
wrote: "Jeff Liebermann" wrote in message .. . On Mon, 13 Jul 2015 13:45:43 +0200, "bilou" wrote: "Jeff Liebermann" wrote in message ... Yep, antennas radiate photons. +1 There is not any proof that RF behaves differently than light. Things are already quite complicated without it :-) One of my not so great ideas was to devise a contraption that would let me "see" RF. It certainly would make troubleshooting RF devices much easier. Essentially, it would be a human eye analog implimented with RF components. According to theory, if it works for light, it should also work for RF. At the time, I was working at about 1GHz. Light is about 400 THz. So, all I need is an eyeball that's 400,000 times larger than the human eye. I'll give myself a -1 for the idea. Wouldn't such a gadget be awesome for adjusting antennas! Yep. I later realized that it would be marginal for RF circuits because I could only see the components and traces that radiate RF. If the circuit was any good, it wouldn't radiate anything. I also burned some time trying to make an RF equivalent to a liquid crystal sheet. http://www.edmundoptics.com/testing-targets/calibration-standards/temperature-sensitive-liquid-crystal-sheets/1642/ Before thermal imagers became relatively inexpensive, I would place a sheet over the power amplifier or whatever, and be able to see the hot spots. I was also somewhat successful at creating a blurry thermal image, using a small germanium lens and one of these sheets. However, the ideal would be to have a liquid crystal sheet that was sensitive to RF instead of heat. I couldn't find anything that detected low frequency RF directly, but did get some interesting effects by screen printing carbon squares on the thermal sensitive liquid crystal sheets. The carbon would get slightly warm from the RF, and cause the color to change. You can also use thermal crayons to get a similar color change with temperatu http://www.tiptemp.com/Products/Color-Changing-Thermal-Paint-Crayons/TLCSEN464-245-Color-Change-Crayon-Kit Long ago, in High Skool, the instructor waved a neon lamp (NE-2) over a transmission line, so that we could see standing waves. I thought that was cool, but would be even better if a had a row of neon lamps so that I didn't need to move the lamp. So, I built one with about 100 NE-2 lamps. Not only could I see the standing waves, but I could also tune the load for minimum SWR. Today, I could probably built something similar out of the LED strip lighting on rolls: http://www.amazon.com/Triangle-Bulbs-T93007-Waterproof-Flexible/dp/B005EHHLD8 However, it would take more power to light up than the NE-2. At 4.8 watts/meter of LED strip, a 20 meter half wave dipole would require 48 watts to fully light at 10 meter long strip. There are admittedly many things wrong with the aforementioned ideas. None of them will work because of obvious (and not-so-obvious) reasons. That's not the point. One has to start somewhere, and started at "close, but not quite" is as good a place as any. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#19
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Do antennas radiate photons?
In article , Jeff Liebermann writes:
let me "see" RF. It certainly would make troubleshooting RF devices much easier. Essentially, it would be a human eye analog implimented with RF components. According to theory, if it works for light, it should also work for RF. At the time, I was working at about 1GHz. Light is about 400 THz. So, all I need is an eyeball that's 400,000 times larger than the human eye. I'll give myself a -1 for the idea. A word: synthetic aperture. Remember the dish arrays in the Jodie Foster movie Contact? You still need the same scale factor - many times the wavelength - but most of a dish array can be air. So with the eyeball analogy, I would first reduce to the size of the pupil - the aperture - and that is perhaps 5 mm. Times 400K gives 2000m for the same theoretical resolution. Of course, for a 2D image you would need an array of antennas spread over a disk of that radius. Or just calculate directly. I think the angular resolution of an array or a telescope in radians is something like 0.22 * wavelength / aperture . Multiply by about 60 to get degrees. So for 1 Ghz (.3m) it's 0.22 * .3m / 2000m, or 33 x 10^-6 radians. About 7 seconds of arc. George |
#20
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Do antennas radiate photons?
In article , I wrote:
A word: synthetic aperture. Drone array, anyone? [...] Or just calculate directly. I think the angular resolution of an array or a telescope in radians is something like 0.22 * wavelength / aperture . Oops. That's 1.22 . Still, I don't think it's too bad considering how long ago I learned about synthetic aperture arrays in 2nd year physics. George |
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