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#1
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In message , Szczepan
Bialek writes "The wire antennas used with crystal receivers are monopole antennas The words "almost always, almost every time, almost invariably and almost without exception" are missing. As crystal receivers are normally used at low frequencies (long and medium wave), the obvious antenna to use is an end-fed long wire monopole. This, of course, requires a ground. However, in principle, you could use a (probably large) dipole, provided you modified/designed the circuit of the receiver so that it would take a balanced input (which would probably also be low impedance). I'm pretty sure that some of the early radar receiving systems used essentially a dipole antenna feeding a crystal receiver. -- Ian |
#2
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![]() "Ian Jackson" napisal w wiadomosci ... In message , Szczepan Bialek writes "The wire antennas used with crystal receivers are monopole antennas The words "almost always, almost every time, almost invariably and almost without exception" are missing. As crystal receivers are normally used at low frequencies (long and medium wave), the obvious antenna to use is an end-fed long wire monopole. This, of course, requires a ground. However, in principle, you could use a (probably large) dipole, provided you modified/designed the circuit of the receiver so that it would take a balanced input (which would probably also be low impedance). I'm pretty sure that some of the early radar receiving systems used essentially a dipole antenna feeding a crystal receiver. You are right: "A simple rectenna element consists of a dipole antenna with a diode connected across the dipole elements." And: "A nantenna is a very small rectenna the size of a light wave, fabricated using nanotechnology, which acts as an "antenna" for light," Each rectenna arm (or dipole element) must be shorter then 1/4 WL. But: "Where the electrons come from? S* |
#3
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In message , Szczepan
Bialek writes "Ian Jackson" napisal w wiadomosci ... In message , Szczepan Bialek writes "The wire antennas used with crystal receivers are monopole antennas The words "almost always, almost every time, almost invariably and almost without exception" are missing. As crystal receivers are normally used at low frequencies (long and medium wave), the obvious antenna to use is an end-fed long wire monopole. This, of course, requires a ground. However, in principle, you could use a (probably large) dipole, provided you modified/designed the circuit of the receiver so that it would take a balanced input (which would probably also be low impedance). I'm pretty sure that some of the early radar receiving systems used essentially a dipole antenna feeding a crystal receiver. You are right: "A simple rectenna element consists of a dipole antenna with a diode connected across the dipole elements." And: "A nantenna is a very small rectenna the size of a light wave, fabricated using nanotechnology, which acts as an "antenna" for light," Each rectenna arm (or dipole element) must be shorter then 1/4 WL. But: "Where the electrons come from? S* The product of a deranged mind? -- Ian |
#4
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Szczepan Bialek wrote:
"Ian Jackson" napisal w wiadomosci ... In message , Szczepan Bialek writes "The wire antennas used with crystal receivers are monopole antennas The words "almost always, almost every time, almost invariably and almost without exception" are missing. As crystal receivers are normally used at low frequencies (long and medium wave), the obvious antenna to use is an end-fed long wire monopole. This, of course, requires a ground. However, in principle, you could use a (probably large) dipole, provided you modified/designed the circuit of the receiver so that it would take a balanced input (which would probably also be low impedance). I'm pretty sure that some of the early radar receiving systems used essentially a dipole antenna feeding a crystal receiver. You are right: "A simple rectenna element consists of a dipole antenna with a diode connected across the dipole elements." And: "A nantenna is a very small rectenna the size of a light wave, fabricated using nanotechnology, which acts as an "antenna" for light," Each rectenna arm (or dipole element) must be shorter then 1/4 WL. But: "Where the electrons come from? S* The same as any other antenna; they are always in the conductor and don't "come" from anywhere. The voltage developed at the antenna terminals causes the electrons in the conductors to move. You are an ignorant, babbling, ineducable idiot who knows absolutely NOTHING about how anything works. An antenna is a device that converts the AC electrical energy at it's teminals into electromagnetic energy which radiates from the antenna and also coverts the electromagnetic energy which antenna intercepts into AC electrical energy at it's terminals. How many antennas have you built in your lifetime? Why do you refuse to answer the question? Is it because you have built zero antennas and you are trying to say all the people that have successfully built hundreds that they are all wrong and you don't want to admit you are an ignorant, inducable, idiot? Why can't you obtain and read a university level textbook on anything in any language? Is it because you are too stupid to be able to understand the material? |
#5
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Ian Jackson wrote:
In message , Szczepan Bialek writes "The wire antennas used with crystal receivers are monopole antennas The words "almost always, almost every time, almost invariably and almost without exception" are missing. As crystal receivers are normally used at low frequencies (long and medium wave), the obvious antenna to use is an end-fed long wire monopole. This, of course, requires a ground. However, in principle, you could use a (probably large) dipole, provided you modified/designed the circuit of the receiver so that it would take a balanced input (which would probably also be low impedance). Or you could use a ferrite antenna with a coupling coil wound to match the impedance. Oh, wait, that would be a coil wound around a ferrite bar with no ground connection whatsoever and no place for jumping electrons. Good Lord, could it possibly work with no jumping electrons and no ground? I'm pretty sure that some of the early radar receiving systems used essentially a dipole antenna feeding a crystal receiver. Yes, some early microwave receivers were in essence crystal sets until the components became available to build the stages necessary for a superheterodyne receiver. Most of the simple Gunn diode based door openers are also basically crystal set receivers. Where do electrons jump from in a horn antenna? |
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