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#1
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A short 160M antenna
"gareth" wrote in message
... "Brian Reay" wrote in message ... His whole grasp of antenna theory is flawed. He was trying to (indirectly) argue the other day via his his interpretation of Maxwell's Equations you could generate an EM wave by waving a magnet about. When corrected, he introduced another variation. Well, Brian, M3OSN, Old Chum, as was pointed out to you, all of your posts these days are personal attacks aimed at one or another. Why do you behave like that? Certainly, as I corrected myself, if you wave a magnet about fast enough, say, 1000,000,000 times per second, you will certainly generate an EM wave and no-one has corrected me on that point because that point is true. I think your arms would start to ache quite quickly. -- ;-) .. 73 de Frank Turner-Smith G3VKI - mine's a pint. .. http://turner-smith.co.uk |
#2
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A short 160M antenna
"FranK Turner-Smith G3VKI" wrote in
: Certainly, as I corrected myself, if you wave a magnet about fast enough, say, 1000,000,000 times per second, you will certainly generate an EM wave and no-one has corrected me on that point because that point is true. I think your arms would start to ache quite quickly. Just a tad... Why would waving a magnet, at ANY speed, do it? I never heard of such. Got to be a stationary conductor involved too, somewhere very nearby. The speed would have far less to do with anything than the matching of kinetic energy into the conductor, and the matching of that to whatever part of that conductor is an antenna. A magnet moving on its own reminds me of the question 'what is the sound of one hand clapping?' |
#3
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A short 160M antenna
Brian Reay wrote in
: Why would waving a magnet, at ANY speed, do it? I never heard of such. Got to be a stationary conductor involved too, somewhere very nearby. The speed would have far less to do with anything than the matching of kinetic energy into the conductor, and the matching of that to whatever part of that conductor is an antenna. Not a moving conductor, a changing electric field. I mentioned stationary conductor, but my example was not rigorous.. He also seems to think that it is frequency which determines if it is an EM wave, why else the comment re fast enough. You can have a ELF radio wave, I know of amateurs with NoVs to operate around 9kHz. Exactly so. That's what I was gettign at, that speed in itself means nothing, it only becomes important when calculations need a frequency. A magnet moving on its own reminds me of the question 'what is the sound of one hand clapping?' An apt comment. |
#4
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A short 160M antenna
On Sat, 08 Nov 2014 06:41:10 -0600, Lostgallifreyan wrote:
An apt comment. And somewhat too deep for this conversation :-) -- M0WYM |
#5
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A short 160M antenna
"Brian Reay" wrote in message
... He isn't the first fool to think he could generate an EM wave breaking Maxwell's laws. You continue to be the one who originates ths abuse that you seek to lay at others' door, and you continue to misunderstand Maxwell. The changing magnetic field cause by rotating a magent at such a speed that it would cease to be a short antennae will create a changing electric field, as described by Maxwell He also seems to think that it is frequency which determines if it is an EM wave, why else the comment re fast enough. Once again you misunderstand, and knowing you, it is a deliberate misunderstanding to give you the chance to be abusive. As to fast enough, see the comment above re no longer bing a short antenna. A magnet moving on its own reminds me of the question 'what is the sound of one hand clapping?' An apt comment. Two ignoramuses do not make for a knowledgeable person. |
#6
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A short 160M antenna
On Sat, 08 Nov 2014 17:46:57 +0000, gareth wrote:
Two ignoramuses do not make for a knowledgeable person. Neither does one really fat ignoramus, so it seems. |
#7
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A short 160M antenna
In rec.radio.amateur.antenna gareth wrote:
"Brian Reay" wrote in message ... He isn't the first fool to think he could generate an EM wave breaking Maxwell's laws. You continue to be the one who originates ths abuse that you seek to lay at others' door, and you continue to misunderstand Maxwell. The changing magnetic field cause by rotating a magent at such a speed that it would cease to be a short antennae will create a changing electric field, as described by Maxwell Babbling nonsense, gas bag, and if you actually understood Maxwell you would know why. He also seems to think that it is frequency which determines if it is an EM wave, why else the comment re fast enough. Once again you misunderstand, and knowing you, it is a deliberate misunderstanding to give you the chance to be abusive. As to fast enough, see the comment above re no longer bing a short antenna. Yet more babbling nonsense, gas bag. A permenant magnet is NOT an antenna of any sort. -- Jim Pennino |
#8
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A short 160M antenna
Jeff wrote in :
On 08/11/2014 17:46, gareth wrote: "Brian Reay" wrote in message ... He isn't the first fool to think he could generate an EM wave breaking Maxwell's laws. You continue to be the one who originates ths abuse that you seek to lay at others' door, and you continue to misunderstand Maxwell. The changing magnetic field cause by rotating a magent at such a speed that it would cease to be a short antennae will create a changing electric field, as described by Maxwell For once have to agree with Gareth, a rotating magnet will cause EM radiation. Jeff *silently munches popcorn, waits for picture to start* |
#9
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A short 160M antenna
Jeff wrote in :
For once have to agree with Gareth, a rotating magnet will cause EM radiation. Ok, maybe so. Is this right...? Suppose a wire is part of a closed circuit, that magnet would certainly induce current. Now, if that wire were NOT closed, but in the form of some antenna, then at an appropriate frequency, in the part of an antenna that normally sees current (at the feedpoint end), you would see a current, thus all the other attributes of an antenna subject to an electromagnetic field would also exist? IF (I'm not stating, just trying to follow a thought based on what you said), IF this is so, then it would mean the EM wave existed with or without the wire, purely because the magnet was spinning. Alternatively, does it just mean that an alternative magnetic field near an antenna feedpoint is as capable of inducing a signal out of the antenna as an electromagnetic wave is? Maybe I should go back to my popcorn. I may not even understand what I see, but I want to watch. |
#10
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A short 160M antenna
Lostgallifreyan wrote in
: IF (I'm not stating, just trying to follow a thought based on what you said), IF this is so, then it would mean the EM wave existed with or without the wire, purely because the magnet was spinning. Ok, scratch that! My own speculation is plain wrong, surely. The earlier point in myearlier post MAY be true, but if so, only because the presence of a nearby antenna feedpoint means that a current carrying wire is actually present. All this, assuming that you can use the current carrying portion of some antenna as if it were a winding in a dynamo, given a magnetic field varying at a rate appropriate for said antenna. Even if this IS possible, it isn't the same as doing an EM wave with no wire at all. That would be magic, no? |
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