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In article ,
says... In article t, Active8 wrote: In article , says... http://www.aftenposten.no/english/lo...ticleID=609108 I've always assumed that the performance of ferrite-rod antennas in transmitting applications was limited by core saturation. Wonder if there's anything to this "invention"? -- jm ------------------------------------------------------ http://www.qsl.net/ke5fx Note: My E-mail address has been altered to avoid spam ------------------------------------------------------ not much info there, but i've read articles about russian experiments on small antennae and something about a capacitive antenna. somewhere in the jumble, i came across a theory/claim supposedly originated by Nikolai Tesla. the theory being that applying a large voltage - low freq. ac, dc... i don't remember - to a short antenna would set up an electrically large antenna by virtue of the electric field. say you applied 1000V to a 1m whip. that's 1000V/m. or it's 1V/m over a length of 1000m effective antenna length. that's the theory... key word "theory". You're misusing the word "theory." You mean hypothesis. I know, I know, I'm nitpicking. But I once was chewed out by a physicist at MIT for misusing the word when I was temping there. Ouch. Al PS: theory - a proven fact which explains an aspect of nature; i.e., the Theory of Relativity. hypotheses - A tentative explanation that accounts for a set of facts and must be proven by further experimentation. yup, it may be nitpicking, but yer right. that was explained on day 1 of 7th grade science. mike |
In article ,
says... In article t, Active8 wrote: In article , says... http://www.aftenposten.no/english/lo...ticleID=609108 I've always assumed that the performance of ferrite-rod antennas in transmitting applications was limited by core saturation. Wonder if there's anything to this "invention"? -- jm ------------------------------------------------------ http://www.qsl.net/ke5fx Note: My E-mail address has been altered to avoid spam ------------------------------------------------------ not much info there, but i've read articles about russian experiments on small antennae and something about a capacitive antenna. somewhere in the jumble, i came across a theory/claim supposedly originated by Nikolai Tesla. the theory being that applying a large voltage - low freq. ac, dc... i don't remember - to a short antenna would set up an electrically large antenna by virtue of the electric field. say you applied 1000V to a 1m whip. that's 1000V/m. or it's 1V/m over a length of 1000m effective antenna length. that's the theory... key word "theory". You're misusing the word "theory." You mean hypothesis. I know, I know, I'm nitpicking. But I once was chewed out by a physicist at MIT for misusing the word when I was temping there. Ouch. Al PS: theory - a proven fact which explains an aspect of nature; i.e., the Theory of Relativity. hypotheses - A tentative explanation that accounts for a set of facts and must be proven by further experimentation. yup, it may be nitpicking, but yer right. that was explained on day 1 of 7th grade science. mike |
On Wed, 17 Sep 2003 05:10:40 GMT, Active8
wrote: In article , says... http://www.aftenposten.no/english/lo...ticleID=609108 Hmmm... sounds bogus to me. somewhere in the jumble, i came across a theory/claim supposedly originated by Nikolai Tesla. the theory being that applying a large voltage - low freq. ac, dc... i don't remember - to a short antenna would set up an electrically large antenna by virtue of the electric field. say you applied 1000V to a 1m whip. that's 1000V/m. or it's 1V/m over a length of 1000m effective antenna length. that's the theory... key word "theory". An antenna has radiation resistance. If you deliver power into Rr, it, well, radiates it. As an antenna gets smaller, its radiation resistance increases, so to dump X watts into space using a smaller antenna, you need to drive it from a higher voltage. P = E^2/Rr. One gadget used to increase the voltage is an "antenna tuner", just a resonant matching network. There are practical limits on how much power you can force into a small antenna: skin effect heating, ionization, matching network Q, stuff like that. Nothing mysterious here. John brs, mike |
On Wed, 17 Sep 2003 05:10:40 GMT, Active8
wrote: In article , says... http://www.aftenposten.no/english/lo...ticleID=609108 Hmmm... sounds bogus to me. somewhere in the jumble, i came across a theory/claim supposedly originated by Nikolai Tesla. the theory being that applying a large voltage - low freq. ac, dc... i don't remember - to a short antenna would set up an electrically large antenna by virtue of the electric field. say you applied 1000V to a 1m whip. that's 1000V/m. or it's 1V/m over a length of 1000m effective antenna length. that's the theory... key word "theory". An antenna has radiation resistance. If you deliver power into Rr, it, well, radiates it. As an antenna gets smaller, its radiation resistance increases, so to dump X watts into space using a smaller antenna, you need to drive it from a higher voltage. P = E^2/Rr. One gadget used to increase the voltage is an "antenna tuner", just a resonant matching network. There are practical limits on how much power you can force into a small antenna: skin effect heating, ionization, matching network Q, stuff like that. Nothing mysterious here. John brs, mike |
"John Miles" wrote http://www.aftenposten.no/english/lo...ticleID=609108 I've always assumed that the performance of ferrite-rod antennas in transmitting applications was limited by core saturation. Wonder if there's anything to this "invention"? I especically like the statement: "Our tiny antenna can be placed in the car or cast in metal, and is at least as good" Great, an antenna working even if cast in metal.... Arie. |
"John Miles" wrote http://www.aftenposten.no/english/lo...ticleID=609108 I've always assumed that the performance of ferrite-rod antennas in transmitting applications was limited by core saturation. Wonder if there's anything to this "invention"? I especically like the statement: "Our tiny antenna can be placed in the car or cast in metal, and is at least as good" Great, an antenna working even if cast in metal.... Arie. |
I especically like the statement: "Our tiny antenna can be placed in the car or cast in metal, and is at least as good" Great, an antenna working even if cast in metal.... Time will tell. It's likely we'll not find out the exact details (if it lives upto ad-bumk that is) but what else can it but a coil wound round a lump of ferrite ? I don;t personally see why a ferrite can be used for transmitting - but then I'd need filling in as to what the technical reasons are for this supposed reasoning is. Clive |
I especically like the statement: "Our tiny antenna can be placed in the car or cast in metal, and is at least as good" Great, an antenna working even if cast in metal.... Time will tell. It's likely we'll not find out the exact details (if it lives upto ad-bumk that is) but what else can it but a coil wound round a lump of ferrite ? I don;t personally see why a ferrite can be used for transmitting - but then I'd need filling in as to what the technical reasons are for this supposed reasoning is. Clive |
read 'can' as 'can't' sorry. |
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