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#1
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On Aug 31, 6:53*am, Richard Fry wrote:
On Aug 30, 9:23*pm, Art Unwin wrote: Exactly because it takes a WL or multiple there of to attain equilibrium Art -- how, then, do you account for the fact that a 1/4-wave monopole and r-f ground system used by many AM broadcast stations produces radiated fields that have been measured to be within a few percent of the maximum possible for the applied power? If "equilibrium" takes a WL or multiple thereof, why are such fractional wavelength radiators so efficient? RF One time response Most hams are aware there are two basic resistances or impedances involved in any antenna. The d.c. wire resistance is a constant whether it is above ground or not. Radiation resistance only occur when radiation is allowed to take place which usually is considered above ground. When the circuit cannot radiate such as in a ground plain or similar then the circuit does not encounter radiation resistance thus the only resistance encountered is the dc resistance which means it draws less power from the source. Thus for a half wave with ground plain it will draw 1/2 the power from the source that a full wave will. So when talking about efficiency per unit of energy supplied the only difference between the two is the wire resistance that is not accompanied by radiation which is extremely small. So overall efficiency changes of a radiator is so small it really is of zero significance. What is important is the ability of an antenna to radiate maximum strength where you want and the ground plain applies a limitation which many can live with. The importance of efficiency is that one is accounting for all forces that impact it where you enter a different mathematical areana which opens up clues to the formation of radiation and possibly other scenarios that can be of benefit in other areas. A case in point. If one has a vertical then the radiation pattern is donut shaped ie it has a hole that is devoid of radiation which is not so good for military servalance. This is because the radiator is oriented opposite to the gravitational force only. If one wants to account for ALL forces involved then one must include with gravity the Corriolis force without which NOTHING can be stable on Earth. One must include it when considering the Earths forces within a arbitrary boundary to achieve equilibrium. Thus to be in equilibrium a radiator must be tipped to include the Coreolis force which then allows for a spherical radiation pattern ala Poynting's vector where the forces within the boundary equals ( and opposite) that outside the boundary and is in a state of equilibrium Thus when a radiator is tipped it now fills up the hole in the donut to obtain radiation that is equal in all directions( equilibrium) which is what a military installation would prefer as possible observation is 100 %. Thus starting with a single radiator that is in equilibrium you are starting from a different point to a planar mode when proceeding with array designs which then becomes educational with respect to possible occurances that are not available to systems outside that of the equilibrium. NUFF SAID |
#2
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Art Unwin wrote:
Thus to be in equilibrium a radiator must be tipped to include the Coreolis force which then allows for a spherical radiation pattern ala Poynting's vector where the forces within the boundary equals ( and opposite) that outside the boundary and is in a state of equilibrium Thus when a radiator is tipped it now fills up the hole in the donut to obtain radiation that is equal in all directions( equilibrium) which is what a military installation would prefer as possible observation is 100 % ____________ Then by your theory does the radiation launched by a vertical, 1/2- wave, center-fed dipole have a different pattern shape when that dipole is tipped away from the vertical plane? I'm referring to the radiation pattern of the dipole itself, not including any reflections. RF |
#3
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![]() "Art Unwin" wrote in message ... snip a bunch of bafflegab... but now a real GEM! he was mumbling about vertical antenna and the hole in the doughnut when they were vertical... Thus when a radiator is tipped it now fills up the hole in the donut to obtain radiation that is equal in all directions( equilibrium) which is what a military installation would prefer as possible observation is 100 %. so now he has FINALLY defined his concept of "equilibrium"... read it forever as isotropic! so his perfect antenna in equilibrium is isotropic or has a gain of zero... to let him sum it up in his own words: NUFF SAID more than enough i would say! |
#4
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On Aug 31, 7:00*pm, "Dave" wrote:
"Art Unwin" wrote in message ... snip a bunch of bafflegab... *but now a real GEM! *he was mumbling about vertical antenna and the hole in the doughnut when they were vertical... Thus when a radiator is tipped it now fills up the hole in the donut to obtain radiation that is equal in all directions( equilibrium) which is what a military installation would prefer as possible observation is 100 %. so now he has FINALLY defined his concept of "equilibrium"... read it forever as isotropic! *so his perfect antenna in equilibrium is isotropic or has a gain of zero... to let him sum it up in his own words: NUFF SAID more than enough i would say! Not bad David. I suppose that can be seen as more modern than equilibrium used centuries ago. Actually isotropic is presently used more by cosmopologists when refering to matter transformations and thus include the latent energy transfer Very good, Now you are on the same road as I (I think) at least until the next insult. ( grin) |
#5
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This is because the radiator is
oriented opposite to the gravitational force only. If one wants to account for ALL forces involved then one must include with gravity the Gravity has no measurable effect on electromagnetic radiation. Thus to be in equilibrium a radiator must be tipped to include the Coreolis force The coriolis force does not effect electromagnetic radiation. which then allows for a spherical radiation pattern ala Poynting's vector where the forces within the boundary equals ( and opposite) that outside the boundary and is in a state of equilibrium How is the Poynting vector related to boundary conditions. What boundary are you talking about? |
#6
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Frank wrote:
This is because the radiator is oriented opposite to the gravitational force only. If one wants to account for ALL forces involved then one must include with gravity the Gravity has no measurable effect on electromagnetic radiation. Actually it does, but it takes something like the gravity of a star to become noticable. -- Jim Pennino Remove .spam.sux to reply. |
#7
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![]() wrote in message ... Frank wrote: This is because the radiator is oriented opposite to the gravitational force only. If one wants to account for ALL forces involved then one must include with gravity the Gravity has no measurable effect on electromagnetic radiation. Actually it does, but it takes something like the gravity of a star to become noticable. True, as in the Einstein experiment with a star close to the eclipsed solar disk. |
#8
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Art Unwin wrote:
boundary to achieve equilibrium. Thus to be in equilibrium a radiator must be tipped to include the Coreolis force which then allows for a spherical radiation pattern ala Poynting's vector where the forces within the boundary equals ( and opposite) that outside the boundary and is in a state of equilibrium Thus when a radiator is tipped it now fills up the hole in the donut to obtain radiation that is equal in all directions( equilibrium) which is what a military installation Ok, so this would mean that at every north or south latitude the angle would be different, and at the equator would be zero, since there's no coriolis effect there. Please give a table that shows the tip angle versus latitude. (Bet you won't because it's secret) And at the north or south pole it's not definable so antennas can't work there.. Why haven't you mentioned these facts before? Bet you haven't because you didn't think of it, but you'll claim otherwise or just not respond. tom K0TAR |
#9
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tom wrote:
Ok, so this would mean that at every north or south latitude the angle would be different, and at the equator would be zero, since there's no coriolis effect there. Please give a table that shows the tip angle versus latitude. (Bet you won't because it's secret) And at the north or south pole it's not definable so antennas can't work there.. I already mentioned that in which case the rifling on a gun would need to be in a different direction depending on the hemisphere, and no rifling would be used at the equator. No answer. Bullets do not use spin to utilize the Coriolis effect, they use spin as gyroscopic stabilization. |
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