h a l f b a k e r yPoint of hors d'oevre
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Why not use the national time signal (so common with "atomic" clocks that set themselves) to power the clock itself. In this digital age of low power intigrated circuitry, and LCD displays, wouldn't there be enough energy in the WWV and/or WWVH time signals to power the very clock using those signals
to calibrate themselves? Or would the power required to drive a pre-amp to receive those signals obviously exceed the amount of power derived from rectifying such a signal?
Halfbakery: Radio Watch
Radio_20Watch
Same idea in a wristwatch. [jutta, Dec 04 2004]
10,000 year clock
http://www.reviewjo.../news/12743310.html
[mrthingy, Dec 04 2004]
[link]
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To answer both questions:
1)No
2)Yes |
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My first instinct is that this hasn't a
chance of working. Then I think that
this isn't a million miles from proposing
a radio powered by the radio signal,
which is exactly what my crystal set
is. |
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[Vernon's] idea linked by [jutta] over there is pretty similar, and has some good links. But I want to encourage [BruceRH90], and Vernon needs no encouragement, so no marks. |
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This idea started me wondering about radio energy again. There is more and more in the news about the need for frequencies for various signals: cell phones, TV, radio etc etc. In densely populated places the radio dial is thick with stations. If a crystal radio can pick up a signal and run off the energy contained in that signal, that represents the energy input by that station alone. What about the sum energy of all broadcast signals? If you could make a crystal radio type device that tapped all at once, maybe you could get some useful work done? |
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At the same time you would drawing energy from the broadcast signal, reducing its ability to do what it was intended to. Remember this energy isn't free, somebody is paying to put it into the air. The more frequencies you harness, the more people you piss off. |
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/the more people you piss off/ Oh dear. What a shame. Poor ClearChannel. |
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[bungston] yeah, poor ambulance service, poor police and fire brigade, poor aircraft, poor mobile phone users......... |
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[bungston]: Antennas only pick up a small portion of the signal that reaches them. Using tuned resonant circuits, it is possible to increase the received signal, but only for the optimized frequency. |
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Imagine that there is a small breeze that blows alternately in two difrections over a swing. If the period of the swing matches the period of oscillation in the air, the swing's oscillations will increase in amplitude until they become significant. If, however, the swing's period does not match the period of the air's oscillations, there will be little or no resonant gain and the swing won't move much at all. |
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On a related note: the science museum in London had a mechanical acoustic amplifier which had a some magnetic beads held by a wire against a rotating surface; one end of the wire was attached to a diaghram, and a coil would attract the beads away from the drum's surface. The idea was that variations in the downward pressure exerted by the beads on the drum would translate into bigger changes of pressure on the wire tugging the diaghram. I have no idea how well this worked, but it might be interesting to apply the principle to something like a crystal radio. |
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As for practicality, though, I think wind-up-generator-powered radios are probably better. Most areas have too many radio stations in too close proximity for crystal sets to work as well as they once did. |
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I had been thinking more about this, and was pleased to find [supercats] explanation here. The question was related to [Belfry's] concern about pissing people off. Imagine I am listening to a radio station. Between me and the radio is a dorm full of nerds, all of whom tune their crystal sets to the frequency I am listening to. Can I notice a difference on my normal radio (with amplified signal). If I am also using a tuned crystal set, can I notice a difference when all of the sets in the dorm tune in? |
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ok people before someone goes off on a rant about how some of you have bats in your belfry I'd like to clear up a misconception here. The radio station always puts out the same signal (for example 50,000watts) No matter how many radios are tuned into it, nothing changes on the transmitter end ok? And all the receivers pick up the same as well no matter how many receivers there are tuned into the station. |
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So you won't be pissing people off k? Well not unless you blast the audio loud enough to shake your neighbor's walls anyway. |
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// I had been thinking more about this, and was pleased to find [supercats] explanation here. The question was related to [Belfry's] concern about pissing people off. Imagine I am listening to a radio station. Between me and the radio is a dorm full of nerds, all of whom tune their crystal sets to the frequency I am listening to. Can I notice a difference on my normal radio (with amplified signal). If I am also using a tuned crystal set, can I notice a difference when all of the sets in the dorm tune in?// |
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I would not expect that any practically-sized receiving antenna would affect the reception of anyone whose distance from the antenna was much larger than the longest dimension of the antenna itself. If all the nerds in a dorm next to yours filled up all available space with antennas, and if the distance between you and their dorm was not large compared to the length over which their aerials were spread, then they might be able to interfere with your reception, but to no greater degree than if they simply set up a grounded metal wall. |
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Between the annos by [ionyou] and [supercat] I think that settles the question of my panfrequency energy collector running up energy costs for a broadcaster or preventing ambulances from hearing their calls. I would just collect energy from all the frequencies that happen by my location. |
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Speaking of EM energy at my location, I wonder if anyone knows of a breakdown of energy delivered to a given area of earth, broken down by wavelength. I imagine almost all is radiant energy in IR/visible/UV spectrum, but maybe there is a lot of energy at other wavelengths too? |
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//Oh dear. What a shame. Poor ClearChannel//Haah. Indeed. |
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I'm still not sure you understand. The energy sent out by the transmitter is already a loss, no matter if you receive it, and use it or not. |
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It's like if you throw a baseball, it doesn't matter if anyone catches it or not. It doesn't matter if it lands on a soft pillow or hits a brick wall. You already put all the energy you ever will for that throw into it when you threw it. You don't "feel" anything after it's caught by the catcher. |
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If the transmitter puts out 100Watts or 50kW, that energy is all that will be sent that instant no matter how many antennas are up receiving it. |
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As for breakdown of energy per wavelength, the higher the frequency, the higher the energy. And as you know frequency and wavelength are inversely proportional. So the smaller the wavelength the higher the energy. |
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You'd be right that most of the energy in any given area is probably in the visible spectrum just from the sheer quantity. |
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You get more energy from a solar cell (yes even in the shade) than from a crystal set radio for example. |
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