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Antenna physical size
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Antenna physical size
On Apr 1, 5:15 pm, wrote:
On Apr 1, 12:32 pm, Art Unwin wrote: On Apr 1, 12:57 pm, wrote: On Apr 1, 9:18 am, Art Unwin wrote: When the air breaks down around an antenna it is because the antenna is not in a state of equilibrium. When a dipole is replaced by a quad ala a series circuit is replaced by a tank circuit it clearly shows that the latter is more efficient.This was firmly proven in Quito.Maximum radiation efficiency requires equilibrium. Period Art If you don't quit spewing all this blatant horse crap, I will be going into talking head mode again. BTW, I'm younger than you are. So your claims of age affecting vulnerability to the effects of constant bafflegab and horse caca will tested at great lengths in such an endeavor. The change of the fabled antenna at HCJB had nothing to do with efficiency. Period. You my friend are a good example of what a redneck thinks. In the past you have bragged about your lack of schooling spouting about the times you didn't go to school. Now you have a license to operate a radio where you can excercise your freedom of speech at will. Unfortunately, as soon as you start vibrating you vocal cords you instantly reveal who and what you are. This is of immense inportance to the rest of us when considering whether to use our precious time to your utterings. Go ahead and be a talking head but you will find that your audio lacks propagation in the subject of antennas Have a happy day and be nice to those around you. You will never know when that last day of yours comes around despite your youthful age. Art Unwin Prior Art... I have never "bragged" about not going to school. I was expelled from school. Which means I really didn't have a whole lot of choice in the matter past that stage. But in the general scheme of things this means little, as most schools don't teach antenna theory unless it's a specific college course. You have never heard my vocal cords vibrate, as you have never talked to me. I doubt if you have even heard me on the air. Being you are so highly educated, why is your spelling so bad? Seems to me you went to school, but either slept through it, or had other things to think about. In any case, you are the last horses ass that should be braying about my education. I educate myself, and have plenty of books laying around. It's funny, I am self educated and oft speak about antennas, but few people have any problems with what I write about. If they do, it's usually some fairly minor detail. You on the other hand, claim to be well educated, but almost everything you spout is challenged as bafflegab, pure untruth, or just plain horse crap. What is wrong with this picture? Prior Art, you make me feel gifted, being I seem to be ahead of you as far as antenna theory, and I didn't take *any* scholarly courses for it. I think you should learn to write and spell a little better if you are going to whine about other peoples lack of education. Your "Queens English" is a mess. What is your excuse for this problem? I absolutely hated English when in school, yet I seem to be doing a bit better writing it than you, even with my sub par education. At least I have an excuse though. Again, you make me feel downright gifted to be on par with such a highly educated man such as yourself. :/ MK Pray tell me then why I am incorrect. You can salvage the answer from your own mind or even from a book. If you are going to decry my explanation you must have the reason at your finger tips. You heard mention of the Tesla coil earlier as a posters sample with respect to a particular point. What the poster did not state was that a Tesla coil is NOT in a state of equilibrium even tho it may be resonant! Why else would energy break out from a circuit in the form of a spark if there was more freedom to travel else where?l Same goes for the old spark plug system, it is not in equilibrium. So go ahead supply an educated reason as to why the sparks emminated from the dipole in Quito and why the closed circuit of a quad pushed the particular problem away. On the other hand give an educated answer to the direction of the three vectors involved in radiation that Harrison cannot give. You say you have books then go a head with respect to these two questions that nobody on this group has been able to resolve. With all the books you say you have then I would agree with you that even a high school drop out can knock hell out of me with respect to antennas. Have a happy day and smile Art. Ps. When younger I passed the Oxford and Cambridge entrance test on English but old age has taken its toll. |
Antenna physical size
"Richard Clark" wrote in message ... On Mon, 31 Mar 2008 23:47:00 +0100, "Mike Kaliski" wrote: Hi Richard, I have a pair of computer speakers sitting on my desk that completely out perform the so called ultimate hi-fi floor mounted tower system speakers I bought 35 years ago for the equivalent of several thousand dollars in today's money. Hi Mike, I have a set of 30 year old Pioneers that still kick ass. The Pioneer amp feeding any other set drives them into distortion where the Pioneer speakers still have more range to go. Never needed to push the amp above 4 to be heard outside. OK, so much for the merits of qualitative reports, otherwise known as testimonials. Proves nothing. The old speakers still work just fine but the audio experts have learned how to squeeze that performance out of a speaker that old audio theory predicted couldn't possibly work. Magnetics got better, and theory stayed the same. Performance followed the theory's prediction of new magnetics is all. This isn't a mystery is it? Care to name your speakers' model and manufacturer, or did you form the cone and wind the voice coils around a selected magnet by hand? 73's Richard Clark, KB7QHC Hi Richard, Never one to refuse a challenge. The old speakers were a pair of Celestion Ditton 15XR's with 30 watt per channel rating and a flat sound response output from around 20Hz to 20kHz, 104db at 1 yard driven with 1 watt. The XR stood for extended range indicating that the speaker design had been modified and upgraded from the original Ditton 15 specifications. The new speakers I mentioned are a pair of Creative T20's. 14 watts per channel from a built in amp and very nice to listen to. They don't really compare with the Celestions for the smooth mellow sound that only seems to come with wooden cabinets, but for the price they are excellent. Good point about the magnets though. The super high powered magnets, ultra rigid, lightweight fibre glass cones and developments in ported cabinet design have all contributed to the superb performance of the T20's. Apparently they have been out for a while now, but it was only when I was wandering about in a PC World store that I heard a pair up and running. I was stopped in my tracks by the sound coming out of these tiny devices and spent a good couple of minutes looking for the subwoofer unit that I felt sure was hidden away somewhere. There wasn't a subwoofer and after that, I just knew I had to buy a pair. I have no connection with Creative and in fact I am a bit annoyed with the company's attitude to (not) providing proper sound card drivers for Windows Vista. Anyway, just go and check out the web reviews. Sorry everyone else, but this bit hasn't really got anything at all to do with antennas. Cheers Mike |
Antenna physical size
"Mike Kaliski" wrote in
: Apparently they have been out for a while now, but it was only when I was wandering about in a PC World store that I heard a pair up and running. I was stopped in my tracks by the sound coming out of these tiny devices and spent a good couple of minutes looking for the subwoofer unit that I felt sure was hidden away somewhere. There wasn't a subwoofer and after that, I just knew I had to buy a pair. I have no connection with Creative and in fact I am a bit annoyed with the company's attitude to (not) providing proper sound card drivers for Windows Vista. Wait for Windows 8. It can't be worse! Anyway, just go and check out the web reviews. Sorry everyone else, but this bit hasn't really got anything at all to do with antennas. What must be really wonderful is how these speaker manufacturers have not only managed to change resonant points, but managed to get these very small systems to move the massive amounts of air needed with the small speaker systems involved! Oops, sorry, I got sarcastic.. While it is true that we can get better sound from smaller speaker systems than we have been able to in the past, we have to keep in mind that those advances are available for the full size systems too. IOW, all things being equal..... No new physics are needed. |
Antenna physical size
On Apr 2, 1:41 pm, Art Unwin wrote:
Pray tell me then why I am incorrect. You can salvage the answer from your own mind or even from a book. When the air breaks down around an antenna it is because the antenna is not in a state of equilibrium. Define equilibrium as it pertains to an antenna. Until you do, it's fairly hard to comment on the first statement. If you have corona discharge from an antenna, it's usually due to sharp points when using wire or a whip with a pointed tip. Thats why they stick round balls on whips, flagpoles, etc.. When a dipole is replaced by a quad ala a series circuit is replaced by a tank circuit it clearly shows that the latter is more efficient. What clearly shows this? This is the statement which drew my comment. The efficiency of a 1/2 WL dipole and a 1 WL loop are so close as to be almost unmeasurable in the real world. But you can take this even farther. Almost *any* size dipole or loop will radiate most all of what is fed to it. A 1/10 WL whip radiates almost all of the power applied to it, same as a 1/4 WL, 1/2 WL, or whatever you want to try. This not not conjecture. This is pretty much written in stone after many years of testing. Why you continue to ignore this simple fact boggles my mind. So your statement is so far from reality I would be amiss in my "talking head" duties if I did not comment. Don't take my word for it. Ask anyone you can think of that has a clue. They will tell you the same thing. What it going to spoil your "full size performance from a dinky radiator" picnic is not the radiator and it's abilities to be an efficient radiator. It's going to be actually feeding the power to such a small radiator and not turning a large amount of RF to heat in the process. No cheating letting the feed line be the antenna.. Look at "small" HF transmitting loops. Do you see any using 22 gauge wire? I doubt it. They will be using the fattest or widest strip of material they can get their hands on. There are other issues involved also in feeding such an antenna. Never do these small loops equal the performance of a full size antenna. They radiate enough to maybe let you operate, and thats about it. This was firmly proven in Quito.Maximum radiation efficiency requires equilibrium. Period Again, the change to quad loops at HCJB was to avoid the sharp points of the dipoles, yagi's, or whatever they were using. In the high alitudes of Quito, HV breakdown at the tips was a serious problem. The change had absolutely nothing to do with antenna efficiency. Not to mention that the whole idea of a loop being more efficient than a dipole is totally wrong. And I don't see how equilibrium has anything to do with it, whatever you might mean by that silly "E" word. Anything else you are curious about? BTW, no grabbing of books were needed to form this response. Art |
Antenna physical size
On Apr 2, 10:37 pm, wrote:
On Apr 2, 1:41 pm, Art Unwin wrote: Pray tell me then why I am incorrect. You can salvage the answer from your own mind or even from a book. When the air breaks down around an antenna it is because the antenna is not in a state of equilibrium. Define equilibrium as it pertains to an antenna. Until you do, it's fairly hard to comment on the first statement. I don't think I can do that for you, it would take to long. If you have corona discharge from an antenna, it's usually due to sharp points when using wire or a whip with a pointed tip. Thats why they stick round balls on whips, flagpoles, etc.. When you have a discharge it is a loss of energy When a dipole is replaced by a quad ala a series circuit is replaced by a tank circuit it clearly shows that the latter is more efficient. What clearly shows this? Well there is no discharge. This is becaquse that there is a route of a lesser impedance available This is the statement which drew my comment. The efficiency of a 1/2 WL dipole and a 1 WL loop are so close as to be almost unmeasurable in the real world. Almost doesn't count when measuring efficiency and in the real world many CAN tell the difference But you can take this even farther. Almost *any* size dipole or loop will radiate most all of what is fed to it. Again you are admitting to lower efficiency when you use the word "most" A 1/10 WL whip radiates almost all of the power applied to it, same as a 1/4 WL, 1/2 WL, or whatever you want to try. This not not conjecture. This is pretty much written in stone after many years of testing. Again you use the word "most" which is admitting less efficiency Why you continue to ignore this simple fact boggles my mind. So your statement is so far from reality I would be amiss in my "talking head" duties if I did not comment. Don't take my word for it. Ask anyone you can think of that has a clue. They will tell you the same thing. What it going to spoil your "full size performance from a dinky radiator" picnic is not the radiator and it's abilities to be an efficient radiator. It's going to be actually feeding the power to such a small radiator and not turning a large amount of RF to heat in the process. No cheating letting the feed line be the antenna.. I think you are missing the point here. My antenna has a full wave length of wire not a fraction there of. So the radiator has the same inductance and capacitance that one would expect from a full wave antenna spread out in a straight line where the wire surface is exposed to the atmosphere, so there is no reason for the energy to circumvent the wire circuit as it must do for a fractional wavelength. Look at "small" HF transmitting loops. Do you see any using 22 gauge wire? I doubt it. They will be using the fattest or widest strip of material they can get their hands on. What you are seeing as representing a loop antenna is a fractional wave length Often it comes with a HV variable capacitor for tuning. The loop that I made was a plastic loop with a full wave length of wire wound upon it. No high voltage capacitor needed as it coveres the whole band. As far as 22 gauge wire being used this is because there is no mechanical stresses imposed on it as would be for a stretched out radiator. So the main consideration is to supply enough skin depth since the diameter itself is not a factor in terms of fusing.current There are other issues involved also in feeding such an antenna. Never do these small loops equal the performance of a full size antenna. They radiate enough to maybe let you operate, and thats about it. If the scource impedance is one that you can match efficiently then you have at hand a efficient radiator of a wavelength where the normal loop you are refering to uses a metal loop as the radiator which is much shorter than a wavelength of wire wound on a plastic loop. The loop is now a small full wave radiator not a small fractional small wave antenna This was firmly proven in Quito.Maximum radiation efficiency requires equilibrium. Period Again, the change to quad loops at HCJB was to avoid the sharp points of the dipoles, yagi's, or whatever they were using. In the high alitudes of Quito, HV breakdown at the tips was a serious problem. The change had absolutely nothing to do with antenna efficiency. If the impedance is to high on the antenna compared to discharging through air to the transmitter ground then that is a very inefficient antenna Not to mention that the whole idea of a loop being more efficient than a dipole is totally wrong. The energy travels easily along the wire circuit without encountering a high impedance that it is forced to take a circuitous route thru ground to the transmitter ground. When the energy is passing thru ground it becomes a loss. And I don't see how equilibrium has anything to do with it, whatever you might mean by that silly "E" word. If a circuit is not balanced and a fractional wave length long it is not in equilibrium!. The energy supplied to the radiator will always encounter a energy wasting impedance in the wire itself if is not at least a wavelength long, and of the right material (diamagnetic) otherwise the energy will seek a route outside the wired circuit which can only lead to losses. Think of it this way, a fractional wave length radiator cannot avoid the energy taking a route thru ground and the ground is a loss. Hopefully you now see antennas in a different light. I do urge you to look up the tank circuit since it is quite an interesting circuit with its phase changes and effective resistances apparently changing without being diverted from the circuit wire confines. Another place where the books are in error is their association with the iron filing magnet experiment at HS which forms a magnetic field very different from that formed from aluminum, copper and other diamagnetic materials. When you pass a time varying current thru copper the magnetic field turns at right angles to the radiator axis and in fact compliments the electrical field vector ( they are not at right angles) Now you can see what lifts or ejects the static particles resting on the surface because they are repelled instead of bing magnetically atracted ( Static: nearly devoid of energy and of small mass) .. So the EH antennas which supposedly combines the EH fields just didn't understand that with a radiator the combination of vectors is already a given! I think you also are making a mistake that many books make when referring to small antennas instead of referring to ELECTRICALLY small antennas Anything else you are curious about? BTW, no grabbing of books were needed to form this response. Art Best regards, no offence intended Art Unwin ......KB9MZ..(uk) |
Antenna physical size
On Thu, 3 Apr 2008 02:33:20 +0100, "Mike Kaliski"
wrote: Hi Richard, Never one to refuse a challenge. The old speakers were a pair of Celestion Ditton 15XR's with 30 watt per channel rating and a flat sound response output from around 20Hz to 20kHz, 104db at 1 yard driven with 1 watt. The XR stood for extended range indicating that the speaker design had been modified and upgraded from the original Ditton 15 specifications. Hi Mike, Pretty impressive. My own Pioneers fall 10dB below that. The new speakers I mentioned are a pair of Creative T20's. 14 watts per channel from a built in amp and very nice to listen to. Good to have a recommendation there too. They don't really compare with the Celestions for the smooth mellow sound that only seems to come with wooden cabinets, but for the price they are excellent. Good point about the magnets though. The super high powered magnets, ultra rigid, lightweight fibre glass cones and developments in ported cabinet design have all contributed to the superb performance of the T20's. Apparently they have been out for a while now, but it was only when I was wandering about in a PC World store that I heard a pair up and running. I was stopped in my tracks by the sound coming out of these tiny devices and spent a good couple of minutes looking for the subwoofer unit that I felt sure was hidden away somewhere. There wasn't a subwoofer and after that, I just knew I had to buy a pair. I would have to agree. I have no connection with Creative and in fact I am a bit annoyed with the company's attitude to (not) providing proper sound card drivers for Windows Vista. Maybe with service pack 4. Anyway, just go and check out the web reviews. I will. Sorry everyone else, but this bit hasn't really got anything at all to do with antennas. But it does show how performance correlates to numbers to theory to practice - something dreadfully missing in Art's contributions, if you can call throwing claims against the wall to see what sticks as a contribution. 73's Richard Clark, KB7QHC |
Antenna physical size
Richard Clark wrote:
But it does show how performance correlates to numbers to theory to practice - something dreadfully missing in Art's contributions, if you can call throwing claims against the wall to see what sticks as a contribution. Or one's underwear... - 73 de Mike N3LI - |
Antenna physical size
On Apr 2, 11:12 pm, Art Unwin wrote:
On Apr 2, 10:37 pm, wrote: On Apr 2, 1:41 pm, Art Unwin wrote: Pray tell me then why I am incorrect. You can salvage the answer from your own mind or even from a book. When the air breaks down around an antenna it is because the antenna is not in a state of equilibrium. Define equilibrium as it pertains to an antenna. Until you do, it's fairly hard to comment on the first statement. I don't think I can do that for you, it would take to long. It hasn't stopped you from writing a novel on other issues.. If you have corona discharge from an antenna, it's usually due to sharp points when using wire or a whip with a pointed tip. Thats why they stick round balls on whips, flagpoles, etc.. When you have a discharge it is a loss of energy Not antenna efficiency though. It's more akin to running a dipole with poor end insulators.. When a dipole is replaced by a quad ala a series circuit is replaced by a tank circuit it clearly shows that the latter is more efficient. What clearly shows this? Well there is no discharge. This is becaquse that there is a route of a lesser impedance available Has nothing to do with antenna efficiency. This is the statement which drew my comment. The efficiency of a 1/2 WL dipole and a 1 WL loop are so close as to be almost unmeasurable in the real world. Almost doesn't count when measuring efficiency and in the real world many CAN tell the difference But you can take this even farther. Almost *any* size dipole or loop will radiate most all of what is fed to it. Again you are admitting to lower efficiency when you use the word "most" The only reason I use "most" is because no real world antenna will radiate 100% of the power applied to it. A 1/10 WL whip radiates almost all of the power applied to it, same as a 1/4 WL, 1/2 WL, or whatever you want to try. This not not conjecture. This is pretty much written in stone after many years of testing. Again you use the word "most" which is admitting less efficiency No, it's admitting that no real antenna will radiate 100% of the power fed to it. Has nothing to do with a comparison of the various types. Why you continue to ignore this simple fact boggles my mind. So your statement is so far from reality I would be amiss in my "talking head" duties if I did not comment. Don't take my word for it. Ask anyone you can think of that has a clue. They will tell you the same thing. What it going to spoil your "full size performance from a dinky radiator" picnic is not the radiator and it's abilities to be an efficient radiator. It's going to be actually feeding the power to such a small radiator and not turning a large amount of RF to heat in the process. No cheating letting the feed line be the antenna.. I think you are missing the point here. My antenna has a full wave length of wire not a fraction there of. So? From it's claimed performance, it's working as a great dummy load. You say it requires no matching to coax, and covers the whole 160m band.. This simple description tells me your antenna is a poor radiator of RF. It shows all the qualities of a air cooled dummy load. A truly efficient antenna of such a small size would require matching to the feedline, would be quite high Q, and the bandwidth would be very narrow. So narrow as to possibly restrict the audio quality of the average 2.5- 3 kc transmitter width .. :( You can actually hear the restriction on the air. I've noticed this many times when people try very small high Q antennas on that band.. This is reciprical, and will be noticed on receive also if you A/B between a full size antenna vs the small version. So the radiator has the same inductance and capacitance that one would expect from a full wave antenna spread out in a straight line You wish... where the wire surface is exposed to the atmosphere, so there is no reason for the energy to circumvent the wire circuit as it must do for a fractional wavelength. Oh, like it does with a 1/2 wave dipole... :/ Look at "small" HF transmitting loops. Do you see any using 22 gauge wire? I doubt it. They will be using the fattest or widest strip of material they can get their hands on. What you are seeing as representing a loop antenna is a fractional wave length Often it comes with a HV variable capacitor for tuning. The loop that I made was a plastic loop with a full wave length of wire wound upon it. No high voltage capacitor needed as it coveres the whole band. Didn't work very well as a radiator of RF did it... Good dummy load though I bet... As far as 22 gauge wire being used this is because there is no mechanical stresses imposed on it as would be for a stretched out radiator. So the main consideration is to supply enough skin depth since the diameter itself is not a factor in terms of fusing.current I didn't know you were trying to construct a fuse box... There are other issues involved also in feeding such an antenna. Never do these small loops equal the performance of a full size antenna. They radiate enough to maybe let you operate, and thats about it. If the scource impedance is one that you can match efficiently then you have at hand a efficient radiator Like a dummy load? of a wavelength where the normal loop you are refering to uses a metal loop as the radiator which is much shorter than a wavelength of wire wound on a plastic loop. The loop is now a small full wave radiator not a small fractional small wave antenna No, it's a small antenna, coil loaded with many feet of 22 gauge wire. In fact, the antenna is pretty much all coil. Not too much different than a wound loopstick used for MW. Their virtues as efficient radiators of RF are about nil.. :( This was firmly proven in Quito.Maximum radiation efficiency requires equilibrium. Period Again, the change to quad loops at HCJB was to avoid the sharp points of the dipoles, yagi's, or whatever they were using. In the high alitudes of Quito, HV breakdown at the tips was a serious problem. The change had absolutely nothing to do with antenna efficiency. If the impedance is to high on the antenna compared to discharging through air to the transmitter ground then that is a very inefficient antenna No. It has nothing to do with antenna efficiency. Antenna efficiency is reciprical from receive to transmit. It's like me taking a nearly fully efficient dipole and running it through a bunch of wet tree branches with poor insulators, and then running high power. An antenna that is truly inefficient will be inefficient on both transmit and receive. Obviously in the case of the dipole, this is not the case. When receiving only, I bet it works just fine. Not to mention that the whole idea of a loop being more efficient than a dipole is totally wrong. The energy travels easily along the wire circuit without encountering a high impedance that it is forced to take a circuitous route thru ground to the transmitter ground. When the energy is passing thru ground it becomes a loss. Where does ground enter the picture? And I don't see how equilibrium has anything to do with it, whatever you might mean by that silly "E" word. If a circuit is not balanced and a fractional wave length long it is not in equilibrium!. But you won't define the E word, so this means little to me... The energy supplied to the radiator will always encounter a energy wasting impedance in the wire itself if is not at least a wavelength long, and of the right material (diamagnetic) Wire resistance does not go away if you use larger lengths of wire vs shorter when using an equal wire gauge. otherwise the energy will seek a route outside the wired circuit which can only lead to losses. Think of it this way, a fractional wave length radiator cannot avoid the energy taking a route thru ground and the ground is a loss. What about the 1/2 wave dipole? Hopefully you now see antennas in a different light. Nope.. Why would I? I do urge you to look up the tank circuit since it is quite an interesting circuit with its phase changes and effective resistances apparently changing without being diverted from the circuit wire confines. I've already read about tank circuits.. Another place where the books are in error is their association with the iron filing magnet experiment at HS which forms a magnetic field very different from that formed from aluminum, copper and other diamagnetic materials. When you pass a time varying current thru copper the magnetic field turns at right angles to the radiator axis and in fact compliments the electrical field vector ( they are not at right angles) Now you can see what lifts or ejects the static particles resting on the surface because they are repelled instead of bing magnetically atracted ( Static: nearly devoid of energy and of small mass) RF is never static.. . So the EH antennas which supposedly combines the EH fields just didn't understand that with a radiator the combination of vectors is already a given! Which means what? I think you also are making a mistake that many books make when referring to small antennas instead of referring to ELECTRICALLY small antennas You are thinking wrong. |
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