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#1
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terry wrote:
.... Looking now at the numbers, you know that the effective power density of the Sun at the surface is 700 watts per square meter. Your skin represents say 1.5 sq meters, so you are getting a total power of say 1 kilowatt. ..... That 700 watts per sq. metre is an interesting number? Bright sun at midday at the equator perhaps? But I doubt that here at around 48 degrees north and with our climate we get anything close to that? Also now wondering how efficient a solar panel is at converting that 700 watts into electric power (for say home use). Which may be why some 'solar' collectors are both photo-voltaic and heat collecting. The scientific name for this measure is Solar Irradiance. If you hold up a square frame 1 meter on a side, perpendicular to the Sun's direction, in space near Earth's orbital distance, about 1400 watts passes the frame - and twice as far from the Sun, that frame only frames a quarter of that amount (of course!) That number 700 W/m^2 takes into account the absorption of power by stuff in the atmosphere, more at slant angles of course. This URL can show the kind of Solar power you can expect at various geographical coordinates. http://re.jrc.ec.europa.eu/pvgis/apps/radday.php You'll see a peak value around noon - and this can be more than 700 W/m^2 at that 48N latitude. Brian W |
#2
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Hey OM
If I look at the node of a source of 20mW and connect 10 wires to that node with equal loads, I will have 2mW going down each wire. No matter how I try and add them up I can't get more than 20 mW. Now I take a 20 mW isotropic emitter, now your'e saying I feed a dish with that 20mW emitter through a feed horn and now all of a sudden I have gain, I have more than 20 mW? Because the dish and feed horn are able to add the particles and waves, where as with 10 wires I cannot add the waves and particles? The only difference in both these are the shape of the dish and the medium used to convey the wave, particles. And you can add the waves particles until you run out of dish. 73 OM de n8zu On Oct 18, 8:40 pm, brian whatcott wrote: terry wrote: ... Looking now at the numbers, you know that the effective power density of the Sun at the surface is 700 watts per square meter. Your skin represents say 1.5 sq meters, so you are getting a total power of say 1 kilowatt. .... That 700 watts per sq. metre is an interesting number? Bright sun at midday at the equator perhaps? But I doubt that here at around 48 degrees north and with our climate we get anything close to that? Also now wondering how efficient a solar panel is at converting that 700 watts into electric power (for say home use). Which may be why some 'solar' collectors are both photo-voltaic and heat collecting. The scientific name for this measure is Solar Irradiance. If you hold up a square frame 1 meter on a side, perpendicular to the Sun's direction, in space near Earth's orbital distance, about 1400 watts passes the frame - and twice as far from the Sun, that frame only frames a quarter of that amount (of course!) That number 700 W/m^2 takes into account the absorption of power by stuff in the atmosphere, more at slant angles of course. This URL can show the kind of Solar power you can expect at various geographical coordinates.http://re.jrc.ec.europa.eu/pvgis/apps/radday.php You'll see a peak value around noon - and this can be more than 700 W/m^2 at that 48N latitude. Brian W |
#3
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raypsi wrote:
Hey OM If I look at the node of a source of 20mW and connect 10 wires to that node with equal loads, I will have 2mW going down each wire. No matter how I try and add them up I can't get more than 20 mW. Now I take a 20 mW isotropic emitter, now your'e saying I feed a dish with that 20mW emitter through a feed horn and now all of a sudden I have gain, I have more than 20 mW? Because the dish and feed horn are able to add the particles and waves, where as with 10 wires I cannot add the waves and particles? The only difference in both these are the shape of the dish and the medium used to convey the wave, particles. And you can add the waves particles until you run out of dish. 73 OM de n8zu Actually your example tends to prove the point that you're questioning. 10 points of 2mw DO add up to 20 mw. The difference with an isotropic radiator is that there are an infinite number of points each at say 20mw. Add 'em up by focusing those points into a single path. If you can rationalize a 20mw transmitter feeding one direction down a feedline or waveguide and still getting 20mw EIRP in ALL directions with an isotropic radiator then it should make sense. -Bill |
#4
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raypsi wrote:
Hey OM If I look at the node of a source of 20mW and connect 10 wires to that node with equal loads, I will have 2mW going down each wire. No matter how I try and add them up I can't get more than 20 mW. Correct. Now I take a 20 mW isotropic emitter, now you're saying I feed a dish with that 20mW emitter through a feed horn and now all of a sudden I have gain, I have more than 20 mW? Not exactly, I am saying you have a gain in power DENSITY i.e watts per sq meter. In a desired direction only, naturally. Like when you use a magnifying glass to collect the Sun's power into a small spot. 73 OM de n8zu |
#5
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Hey OM:
I tell you what. I took just 1 particle wave and shoot the particle wave into a 60db dish. At the focus I got 1,000,000 partivle waves. I mean that is 60 db right? So where did the other 999,999 particles come from? Energy density from focusing just one particle? The two slot experiment buttresses the above. Take 2 parallel slots shoot just one particle wave into just one slot and 2 particle waves come out the other side. 73 OM de n8zu |
#6
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Take a small light bulb, it shines light in many directions.
Place this at the focal point of a mirrored parabolic dish and the light is predominantly directed in one direction. In the direction that the dish is pointing, and at a distance, measure the received light using a light meter. Remove the dish, and at the same distance, measure the received light using a light meter from the naked bulb. One measurement will be higher than the other. Why do you think this might be ? On Oct 24, 5:24*am, raypsi wrote: Hey OM: I tell you what. I took just 1 particle wave and shoot the particle wave into a 60db dish. At the focus I got 1,000,000 partivle waves. I mean that is 60 db right? So where did the other 999,999 particles come from? Energy density from focusing just one particle? The two slot experiment buttresses the above. Take 2 parallel slots shoot just one particle wave into just one slot and 2 particle waves come out the other side. 73 OM de n8zu |
#7
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Nice concrete example, Mark.
The same conclusion holds if the bulb is so dim, that it only emits one photon at intervals. Brian W MarkAren wrote: Take a small light bulb, it shines light in many directions. Place this at the focal point of a mirrored parabolic dish and the light is predominantly directed in one direction. In the direction that the dish is pointing, and at a distance, measure the received light using a light meter. Remove the dish, and at the same distance, measure the received light using a light meter from the naked bulb. One measurement will be higher than the other. Why do you think this might be ? On Oct 24, 5:24 am, raypsi wrote: Hey OM: I tell you what. I took just 1 particle wave and shoot the particle wave into a 60db dish. At the focus I got 1,000,000 partivle waves. I mean that is 60 db right? So where did the other 999,999 particles come from? Energy density from focusing just one particle? The two slot experiment buttresses the above. Take 2 parallel slots shoot just one particle wave into just one slot and 2 particle waves come out the other side. 73 OM de n8zu |
#8
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raypsi wrote:
Hey OM: I tell you what. I took just 1 particle wave [ per sq meter] and shoot the particle wave into a 60db dish. At the focus I got 1,000,000 particle waves [ per sq meter]. I mean that is 60 db right? Yes. So where did the other 999,999 particles come from? Energy density from focusing just one particle? NOW, you're getting it! No more particles, but more particle density, when the flux is directed tightly... The two slot experiment buttresses the above. Take 2 parallel slots shoot just one particle wave into just one slot and 2 particle waves come out the other side. 73 OM de n8zu Actually no. But you probably realized that. Or did you? I am not pursuing this much further, because you are starting to respond like a person who wants to drag out an argument. Listen to me when I say: "I can be wrong. I often am." Can you say that too, with some sincerity? :-) Brian W :-) |
#9
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![]() Hey OM By golly ole timer you hit the nail on the head. I don't pay no stinking taxes, in the W-4 form I put "EXEMPT" where it asks for number of deductions, and when I file my 1040 it says at the end of the form REFUND DUE, in four figures, for the last several years. Now that is legit, but it sure is WRONG, at least that is what everyone tells me. Your trouble is you pay taxes, where as I don't. Now that is energy density. 73 OM de n8zu On Oct 23, 8:25 pm, brian whatcott wrote: raypsi wrote: Hey OM: I tell you what. I took just 1 particle wave [ per sq meter] and shoot the particle wave into a 60db dish. At the focus I got 1,000,000 particle waves [ per sq meter]. I mean that is 60 db right? Yes. So where did the other 999,999 particles come from? Energy density from focusing just one particle? NOW, you're getting it! No more particles, but more particle density, when the flux is directed tightly... The two slot experiment buttresses the above. Take 2 parallel slots shoot just one particle wave into just one slot and 2 particle waves come out the other side. 73 OM de n8zu Actually no. But you probably realized that. Or did you? I am not pursuing this much further, because you are starting to respond like a person who wants to drag out an argument. Listen to me when I say: "I can be wrong. I often am." Can you say that too, with some sincerity? :-) Brian W :-) |
#10
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raypsi wrote:
Hey OM By golly ole timer you hit the nail on the head. I don't pay no stinking taxes, in the W-4 form I put "EXEMPT" where it asks for number of deductions, and when I file my 1040 it says at the end of the form REFUND DUE, in four figures, for the last several years. Now that is legit, but it sure is WRONG, at least that is what everyone tells me. Your trouble is you pay taxes, where as I don't. Now that is energy density. 73 OM de n8zu Ah, now I see the real 'problem' ![]() -Bill |
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