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BJ radionut posted:

"The Isotropic antenna technically only exists in a vacuum."

the isotropic radiator radiator doesn't exist, it's based on a theoretical construct.

isotropic (source) radiator

the point of origin for the purely omnidirectional radiation of electromagnetic energy located at the absolute center of a sphere which radiates energy of equal intensity at all points of the inner surface (effective area) of the sphere. the isotropic radiator exists only in theory since construction is impossible but it is useful as a reference by which to gauge the directivity of electromagnetic radiators.

the directivity of the isotropic radiator is 0 dB. and the power multiplier ratio is 1.

from this reference point it is clear that any effort to concentrate or focus the energy produced by the radiator (for example, the addition of a parabolic reflector) in an effort to increase the intensity of the radiation to any fractional area of the internal surface of the sphere will distract from the intensity of the radiation in the direction of large portions of the sphere's internal surface and will produce an increase in directivity in the favored direction relative to the placement of the reflector element with respect to the radiator.

https://www.worldwidedx.com/threads/best-low-cost-intro-beam.261866/page-3#post-764374

<blockquote data-quote="freecell" data-source="post: 765777" data-attributes="member: 30">BJ radionut posted:&quot;The Isotropic antenna technically only exists in a vacuum.&quot;the isotropic radiator radiator doesn&#039;t exist, it&#039;s based on a theoretical construct.isotropic (source) radiatorthe point of origin for the purely omnidirectional radiation of electromagnetic energy located at the absolute center of a sphere which radiates energy of equal intensity at all points of the inner surface (effective area) of the sphere. the isotropic radiator exists only in theory since construction is impossible but it is useful as a reference by which to gauge the directivity of electromagnetic radiators.the directivity of the isotropic radiator is 0 dB. and the power multiplier ratio is 1.from this reference point it is clear that any effort to concentrate or focus the energy produced by the radiator (for example, the addition of a parabolic reflector) in an effort to increase the intensity of the radiation to any fractional area of the internal surface of the sphere will distract from the intensity of the radiation in the direction of large portions of the sphere&#039;s internal surface and will produce an increase in directivity in the favored direction relative to the placement of the reflector element with respect to the radiator.<a href="https://www.worldwidedx.com/threads/best-low-cost-intro-beam.261866/page-3#post-764374" target="_blank">https://www.worldwidedx.com/threads/best-low-cost-intro-beam.261866/page-3#post-764374</a></blockquote>

[QUOTE="freecell, post: 765777, member: 30"] BJ radionut posted: "The Isotropic antenna technically only exists in a vacuum." the isotropic radiator radiator doesn't exist, it's based on a theoretical construct. isotropic (source) radiator the point of origin for the purely omnidirectional radiation of electromagnetic energy located at the absolute center of a sphere which radiates energy of equal intensity at all points of the inner surface (effective area) of the sphere. the isotropic radiator exists only in theory since construction is impossible but it is useful as a reference by which to gauge the directivity of electromagnetic radiators. the directivity of the isotropic radiator is 0 dB. and the power multiplier ratio is 1. from this reference point it is clear that any effort to concentrate or focus the energy produced by the radiator (for example, the addition of a parabolic reflector) in an effort to increase the intensity of the radiation to any fractional area of the internal surface of the sphere will distract from the intensity of the radiation in the direction of large portions of the sphere's internal surface and will produce an increase in directivity in the favored direction relative to the placement of the reflector element with respect to the radiator. [URL]https://www.worldwidedx.com/threads/best-low-cost-intro-beam.261866/page-3#post-764374[/URL] [/QUOTE]

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