71–80 of 163 posts
I was once in a completely empty swimming pool (~25*10 m size) The surface of the pool was completely undisturbed. When I put my head under water I could hear a radio voice. Since I could not rule out the possibility that it was simply audio from nearby speakers that I simply could not hear through the air, I was always wondering whether it would be possible to listen to radio waves in water.
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The bird would be dead. RF power will happily fry tissue if you get close enough to the radiator.
Excuse my ignorance, but wouldn't the bird need to be grounded for the power to jump? Or does that only apply to electrical circuits?
I can’t watch this video without an account. A click on the video leads me to the login page. Is there a mirror?
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The voltage applied to the cable is directly proportional to the audio signal, overlaid on a ~1 MHz carrier. All you need is a mechanism that transforms those voltages into vibrations or pressure waves. Presumably, since it seems to happen only when he's striking an arc, it's related to the local heating of the air in the gap ... But I guess it could be electromagnetically induced vibrations of the cable or the tower…
That was one specific station - the infamous WLW / W8XO - the first and only US station authorized to operate at 500kW of power.[1] To give you an idea of how powerful that is, take a look at their coverage map: http://i.imgur.com/Aigz1Zh.jpg The back story is kind of interesting. It was run by Powel Crosley - a sort of 1930's version of Elon Musk. Advertising revenues from the station were so successful he applied t…
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> What 50 kilowatts of RF power sounds like through a jumper cable And you still got it wrong.
What's wrong with it?
I don't think it's a capitalisation problem; when using 'Watt' as a name, e.g. James Watt, you need to capitalise. But the unit is 'watt', with a lower-case 'w'. The symbol is an uppercase W. Reference: Table 3, in "NIST Special Publication 330: The international System of Units (SI)", Taylor et al (2008).
Nor do I think there's a problem with confusing energy and power, as there currently is in the original title.
So, what's the problem? Jaquesm's "And you still got it wrong" comment is unhelpful because it doesn't identify a specific problem. Maybe he feels that the sound doesn't actually come from the cable. Or maybe the cable isn't carrying 50 kW. I don't know. Maybe there is an obvious problem I'm missing.
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I think "40 W of light" is a great example of why this imprecise, or quite frankly, incorrect usage is troublesome. 40 W of old timey lightbulb light is useful if you want to sit close and read a book in the evening, whereas 40 W of a modern LED bulb light is a great thing to have if you want to fend of a pack of marauding undead.
"40 W of light" in physics terms is quite unambiguous, it means 40 W in radiant flux.
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That was one specific station - the infamous WLW / W8XO - the first and only US station authorized to operate at 500kW of power.[1] To give you an idea of how powerful that is, take a look at their coverage map: http://i.imgur.com/Aigz1Zh.jpg The back story is kind of interesting. It was run by Powel Crosley - a sort of 1930's version of Elon Musk. Advertising revenues from the station were so successful he applied t…
Actually, Solt is not Middle East, but in Central Europe. (I live ~50 km from it.) But yes, it's 2 MW, and at night, it can be heard using conventional receivers as far as Belgium.
Does a tower like this only broadcast one radio station? That's not what I would have naively expected. But if not, why do they pick up that specific one?
http://www.radioworld.com/article/four-am-stations-sharing-o...
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The voltage applied to the cable is directly proportional to the audio signal, overlaid on a ~1 MHz carrier. All you need is a mechanism that transforms those voltages into vibrations or pressure waves. Presumably, since it seems to happen only when he's striking an arc, it's related to the local heating of the air in the gap ... But I guess it could be electromagnetically induced vibrations of the cable or the tower…
I have a friend who lives as close as one can legally live to a 100kW FM transmitter. He received a pair of very cheap speakers when he built a new computer but was unable to use them because if they were plugged in the radio signal would come right out of the speakers. It seemed that the signal path into the speakers was through the input wire (rather than, say, the power cable or the wires between the amplifier and…