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Antenna physical size
wrote in message ... 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. you might as well plonk him, he is either a persistent troll or totally convinced that only he has the proper view of the world. in either case you are fighting a losing battle. |
Antenna physical size
On Apr 4, 7:02 pm, "Dave" wrote:
wrote in message ... 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. you might as well plonk him, he is either a persistent troll or totally convinced that only he has the proper view of the world. in either case you are fighting a losing battle. |
Antenna physical size
On Apr 4, 7:02 pm, "Dave" wrote: You are thinking wrong. you might as well plonk him, he is either a persistent troll or totally convinced that only he has the proper view of the world. in either case you are fighting a losing battle. Two perfect examples of a closed mind, but not to worry enlightenment will be along shortly. Derek |
Antenna physical size
wrote in message ... On Apr 4, 7:02 pm, "Dave" wrote: You are thinking wrong. you might as well plonk him, he is either a persistent troll or totally convinced that only he has the proper view of the world. in either case you are fighting a losing battle. Two perfect examples of a closed mind, but not to worry enlightenment will be along shortly. Derek please do enlighten us, art has failed miserably in that. i would love to find out his antenna works as good as a full size half wave dipole and only had to be tilted and turned on a tiny rotor... sure would be easier to maintain than my current aluminum farm. |
Antenna physical size
On Apr 4, 8:08 am, wrote:
On Apr 4, 7:02 pm, "Dave" wrote: You are thinking wrong. you might as well plonk him, he is either a persistent troll or totally convinced that only he has the proper view of the world. in either case you are fighting a losing battle. Two perfect examples of a closed mind, but not to worry enlightenment will be along shortly. Derek I thought I would share with you my readings on the 160 M band They are in order as follows Freq, resistance, reactance swr 1.8 105 0 2.1 1.81 105 0 2.0 1.82 105 0 2.0 1.83 105 0 2.0 1.84 102 0 2.0 1.85 98 0 1.9 1.86 92 0 1.8 1.87 88 6 1.7 1.88 83 7 1.7 1.89 84 8 1.7 1.9 81 12 1.6 1.91 78 13 1.6 1.92 75 12 1.5 1.93 72 13 1.5 1.94 68 11 1.4 1.95 67 10 1.4 1.96 66 10 1.3 1.97 64 9 1.3 1.98 62 9 1.3 1.99 62 9 1.3 2.0 62 7 1.2 The above figures are obtained by ensuring no external inductance and capacitances were introduced to the intrinsic radiation circuit during assembly. As one would expect, the above figures would represent the features through out the frequency range Impedance values mainly resistance will change according to the point of jumper connection of wire supplied. This allows for lossless matching to the drive circuit regardles of its impedance value. Those you are familiar with antennas will see that the above figures in no way represent those of a dummy load 'The above figures show an excellent match to 75 ohm cable. Thge figures were taken with a mfj 259b which is designed for 50 ohm cables. TGIF Art Unwin |
Antenna physical size
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Antenna physical size
On Apr 4, 3:24 pm, Michael Coslo wrote:
wrote: On Apr 4, 7:02 pm, "Dave" wrote: You are thinking wrong. you might as well plonk him, he is either a persistent troll or totally convinced that only he has the proper view of the world. in either case you are fighting a losing battle. Two perfect examples of a closed mind, but not to worry enlightenment will be along shortly. And always will be, just like modern washday miracles and Dishwashers that don't leave spots on glasses. ;^) An open mind does not mean suspension of all disbelief.... - 73 de Mike N3LI - Mike, you asked for a lot of details about the antenna such that I thought you were going to make one. What happened I expected you to come forward with confirmation in a lot of areas! I thought you were a doer not a talking head. Art |
Antenna physical size
On Apr 4, 9:22 am, Art Unwin wrote:
Two perfect examples of a closed mind, but not to worry enlightenment will be along shortly. Derek I already own a flashlight. Several in fact. I thought I would share with you my readings on the 160 M band They are in order as follows Freq, resistance, reactance swr 1.8 105 0 2.1 1.81 105 0 2.0 1.82 105 0 2.0 1.83 105 0 2.0 1.84 102 0 2.0 1.85 98 0 1.9 1.86 92 0 1.8 1.87 88 6 1.7 1.88 83 7 1.7 1.89 84 8 1.7 1.9 81 12 1.6 1.91 78 13 1.6 1.92 75 12 1.5 1.93 72 13 1.5 1.94 68 11 1.4 1.95 67 10 1.4 1.96 66 10 1.3 1.97 64 9 1.3 1.98 62 9 1.3 1.99 62 9 1.3 2.0 62 7 1.2 Those you are familiar with antennas will see that the above figures in no way represent those of a dummy load I've seen light bulbs act the same way when rf was fed to them. How many people do you know that use a light bulb as an antenna? I used one as a dummy load when I was a novice. It was enlightening, I have to admit that... :/ |
Antenna physical size
On Apr 4, 4:01 pm, wrote:
On Apr 4, 9:22 am, Art Unwin wrote: Two perfect examples of a closed mind, but not to worry enlightenment will be along shortly. Derek I already own a flashlight. Several in fact. I thought I would share with you my readings on the 160 M band They are in order as follows Freq, resistance, reactance swr 1.8 105 0 2.1 1.81 105 0 2.0 1.82 105 0 2.0 1.83 105 0 2.0 1.84 102 0 2.0 1.85 98 0 1.9 1.86 92 0 1.8 1.87 88 6 1.7 1.88 83 7 1.7 1.89 84 8 1.7 1.9 81 12 1.6 1.91 78 13 1.6 1.92 75 12 1.5 1.93 72 13 1.5 1.94 68 11 1.4 1.95 67 10 1.4 1.96 66 10 1.3 1.97 64 9 1.3 1.98 62 9 1.3 1.99 62 9 1.3 2.0 62 7 1.2 Those you are familiar with antennas will see that the above figures in no way represent those of a dummy load I've seen light bulbs act the same way when rf was fed to them. How many people do you know that use a light bulb as an antenna? I used one as a dummy load when I was a novice. It was enlightening, I have to admit that... :/ While listening to Europe coming in with 5/9 signasl, I thought that everybody should be using "dummy loads" Art |
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