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The ultimate tilted monopole
In the words of the great Basil Fawlty "you'll like this one"!
It appears to be believed, by one or two who frequent this NG, that a tilted monopole provides more gain and somehow 'better' EM radiation than a vertical one. However, we've seen that tilting a vertical monopole distorts its radiation pattern so it is no longer truly omni-directional in the horizontal plane. Then why not create an array of such tilted monopoles, all tilted in different directions, to restore the omni-directional pattern. The result is a discone antenna, or a discage like the one illustrated at http://gvarc.us/GVARCFrames/Titan/Di...ch4life002.jpg. I wonder what the 'new-age theorists' would make of this. Does it require the Coriolis effect to analyse it, or is the old-fashioned version provided by Schellkunoff & Friis(#) still adequate? Chris # Schellkunoff, S.A., and Friis, H.T. Antennas, theory and practice. John Wiley & Sons Inc., New York, 1952. pp 104 to 106. .... and if that isn't enough, how about the Racal Antennas 'Difan' http://www.racalantennas.com/product...45-30mhz.aspx? |
The ultimate tilted monopole
"christofire" wrote in message ... In the words of the great Basil Fawlty "you'll like this one"! It appears to be believed, by one or two who frequent this NG, that a tilted monopole provides more gain and somehow 'better' EM radiation than a vertical one. However, we've seen that tilting a vertical monopole distorts its radiation pattern so it is no longer truly omni-directional in the horizontal plane. Then why not create an array of such tilted monopoles, all tilted in different directions, to restore the omni-directional pattern. The result is a discone antenna, or a discage like the one illustrated at http://gvarc.us/GVARCFrames/Titan/Di...ch4life002.jpg. I wonder what the 'new-age theorists' would make of this. Does it require the Coriolis effect to analyse it, or is the old-fashioned version provided by Schellkunoff & Friis(#) still adequate? Chris # Schellkunoff, S.A., and Friis, H.T. Antennas, theory and practice. John Wiley & Sons Inc., New York, 1952. pp 104 to 106. ... and if that isn't enough, how about the Racal Antennas 'Difan' http://www.racalantennas.com/product...45-30mhz.aspx? It makes one wonder how they "stumbled" onto these designs without a knowledge of equalibrium and coriolis. I can already see Art's reply- how do you know they did not take these into account? My only answer is- because you're the only one that does. Dale W4OP |
The ultimate tilted monopole
"christofire" wrote in message ... In the words of the great Basil Fawlty "you'll like this one"! It appears to be believed, by one or two who frequent this NG, that a tilted monopole provides more gain and somehow 'better' EM radiation than a vertical one. However, we've seen that tilting a vertical monopole distorts its radiation pattern so it is no longer truly omni-directional in the horizontal plane. Then why not create an array of such tilted monopoles, all tilted in different directions, to restore the omni-directional pattern. The result is a discone antenna, or a discage like the one illustrated at http://gvarc.us/GVARCFrames/Titan/Di...ch4life002.jpg. I wonder what the 'new-age theorists' would make of this. Does it require the Coriolis effect to analyse it, or is the old-fashioned version provided by Schellkunoff & Friis(#) still adequate? Also a receive-only HF antenna the Navy mounted on the forward gun mount. I struggled to find a picture of a ship with one showing but no luck. The elements were about five to seven feet long and arranged as the OP describes |
The ultimate tilted monopole
"christofire" wrote in message ... In the words of the great Basil Fawlty "you'll like this one"! It appears to be believed, by one or two who frequent this NG, that a tilted monopole provides more gain and somehow 'better' EM radiation than a vertical one. However, we've seen that tilting a vertical monopole distorts its radiation pattern so it is no longer truly omni-directional in the horizontal plane. Then why not create an array of such tilted monopoles, all tilted in different directions, to restore the omni-directional pattern. The result is a discone antenna, or a discage like the one illustrated at http://gvarc.us/GVARCFrames/Titan/Di...ch4life002.jpg. I wonder what the 'new-age theorists' would make of this. Does it require the Coriolis effect to analyse it, or is the old-fashioned version provided by Schellkunoff & Friis(#) still adequate? Such a design also appears as a self-supporting HF receive antenna the Navy mounted on the forward gun mount. I struggled to find a picture of a ship with one showing but no luck. The elements were about five to seven feet long and arranged as the OP describes. |
The ultimate tilted monopole
"christofire" wrote in message ... In the words of the great Basil Fawlty "you'll like this one"! It appears to be believed, by one or two who frequent this NG, that a tilted monopole provides more gain and somehow 'better' EM radiation than a vertical one. However, we've seen that tilting a vertical monopole distorts its radiation pattern so it is no longer truly omni-directional in the horizontal plane. Then why not create an array of such tilted monopoles, all tilted in different directions, to restore the omni-directional pattern. The result is a discone antenna, or a discage like the one illustrated at http://gvarc.us/GVARCFrames/Titan/Di...ch4life002.jpg. I wonder what the 'new-age theorists' would make of this. Does it require the Coriolis effect to analyse it, or is the old-fashioned version provided by Schellkunoff & Friis(#) still adequate? Such a design also appears as a self-supporting HF receive antenna the Navy mounted on the forward gun mount. I struggled to find a picture of a ship with one showing but no luck. The elements were about five to seven feet long and arranged as the OP describes. |
The ultimate tilted monopole
On Sep 7, 6:44*pm, "christofire" wrote:
It appears to be believed, by one or two who frequent this NG, that a tilted monopole provides more gain and somehow 'better' EM radiation than a vertical one. *However, we've seen that tilting a vertical monopole distorts its radiation pattern so it is no longer truly omni-directional in the horizontal plane. *Then why not create an array of such tilted monopoles, all tilted in different directions, to restore the omni-directional pattern. |
The ultimate tilted monopole
"Sal M. Onella" wrote in message ... "christofire" wrote in message ... In the words of the great Basil Fawlty "you'll like this one"! It appears to be believed, by one or two who frequent this NG, that a tilted monopole provides more gain and somehow 'better' EM radiation than a vertical one. However, we've seen that tilting a vertical monopole distorts its radiation pattern so it is no longer truly omni-directional in the horizontal plane. Then why not create an array of such tilted monopoles, all tilted in different directions, to restore the omni-directional pattern. The result is a discone antenna, or a discage like the one illustrated at http://gvarc.us/GVARCFrames/Titan/Di...ch4life002.jpg. I wonder what the 'new-age theorists' would make of this. Does it require the Coriolis effect to analyse it, or is the old-fashioned version provided by Schellkunoff & Friis(#) still adequate? Such a design also appears as a self-supporting HF receive antenna the Navy mounted on the forward gun mount. I struggled to find a picture of a ship with one showing but no luck. The elements were about five to seven feet long and arranged as the OP describes. USS Missouri http://www.kh6bb.org/photos2.html Chris |
The ultimate tilted monopole
In the case of a single monopole mounted with its base at earth level,
adding tilt to it makes very little difference in its gain at elevation angles up to +60 degrees or so, at any azimuth. It does partially fill the elevation null at the zenith produced by the vertical monopole, as well as to produce a small amount of h-pol radiation over most of the compass. Modeling this in NEC for a 1 MHz, 1/4-wave, straight monopole by moving its top 10 meters out of plumb changed its peak gain by about 0.01 dB compared to the untilted version, at any azimuth. RF |
The ultimate tilted monopole
On Sep 8, 11:00*am, Richard Fry wrote:
In the case of a single monopole mounted with its base at earth level, adding tilt to it makes very little difference in its gain at elevation angles up to +60 degrees or so, at any azimuth. *It does partially fill the elevation null at the zenith produced by the vertical monopole, as well as to produce a small amount of h-pol radiation over most of the compass. Modeling this in NEC for a 1 MHz, 1/4-wave, straight monopole by moving its top 10 meters out of plumb changed its peak gain by about 0.01 dB compared to the untilted version, at any azimuth. RF Gain has never been as issue in tipping the radiator except for some who which to interject it. Pointing's vector shows a radiation patterm that is spherical and in a state of equilibrium It is not the radiation pattern of a donut which all are familiar with. Thus if one wants coverage in all directions one must pursue an array or conductor in equilibrium. The present state of the art only considers gravity as being outside the arbitrary border such that the equal and opposite vecter is exactly that. ie at right angles to the Earth's surface. Now we all know that the radiation pattern of such does not remotely resemble that of Pointings vector! To get to the point of a spherical radiation pattern one must recognize that there is an additional vector outside the boundary that one must consider to obtain equilibrium. So far you have shown progress by tipping the radiator where it started to fill the void at the center of the donut. This alone confirms the idea that another vector has to be considered outside the arbitrary border. Now rotation is an essential property of the Universe as fracture of an arbitrary boundary is created by two forces which are not on a common plane. This is a shear force which also creates torque or spin ,so it stands to reason that the other force in combination with gravity is a force of torque or rotation. If Coriolis is not that vector what other characteristic fits the bill? |
The ultimate tilted monopole
On Sep 8, 12:30*pm, Art Unwin wrote:
So far you have shown progress by tipping the radiator where it started to fill the void at the center of the donut. This alone confirms the idea that another vector has to be considered outside the arbitrary border The change in the elevation pattern shape and gains seen in the "tipped" NEC plot I posted are NOT due to equilibrium, vectors outside boundaries, shear forces, torque, spin etc. The change in the pattern of the tipped vertical dipole are due to changes in the amount and direction of the energy radiated toward the earth by, and near the antenna, and the net field that results by the vector addition of that reflection with the energy radiated in a given direction by the dipole itself. Suggest you use NEC to model a vertical dipole in free space, at several physical rotation angles away from plumb. See if the gain and shape of the radiation pattern changes (they won't, if your model is valid). Also note that the Poynting vector does not take the form of a perfect sphere for any linear antenna -- only for a (non-existent) isotropic radiator. RF |
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