This afternoon I'm exploring antenna radiation resistance and efficiency as discussed in the American Radio Relay League's Extra Class Examination Manual Ninth Edition (2011) authored by Ward Silver, N0AX.
Is there a relationship between antenna radiation resistance and Micro dB Theory? What is antenna efficiency and its relationship if any to the same theory?
Silver (2011) stated, supplied energy to one's antenna is dissipated either as a radio wave or as heat in the wire additionally; nearby objects such as fencing; a brick; or shrubbery will absorb the same energy.
Certainly, when considering micro-iteration at one's antenna system, maximizing energy as a radio wave is inherently better than lost heat in the wire.
Two types of resistances are accounted for in one's antenna system, according the author; that is radiated power and the other is heat as a function of loss. Ideally, one wants effective radiated power over that of power lost as heat and Silver described heat resistance (R) as real or ohmic (2011).
The second accounting of (R) is theoretical or assumed resistance, if present; it dissipates the power radiated by one's antenna system (2011). Theoretical or assumed power is referenced as radiation resistance.
Ohmic resistance physically debits one's antenna system as a function of heat. However, theoretical or assumed radiation, is an antenna system construction credit. Silver explained it this way, "It is reasonable to assume that the ohmic (heat) loss in a reasonably located antenna is negligible and that all of the resistance shown by the antenna is radiation resistance" (p 9.5, 2011).
Antenna efficiency is a function of radiation resistance divided by total resistance multiplied by 100% according to Silver (2011). As radiation resistance decreases then ohmic (heat) resistance or antenna loss increases as a function of heat. The following variables, according to the author (2011), should be factored into antenna deployment and construction; location of objects near the antenna with emphasis on earth, and the length and diameter ratio of chosen conductor.
Lastly, I recommend reading further about antenna efficiency, because Silver discussed the effect of height and ground on that of a quarter wavelength vertical antenna system, on page 9-6 of the Amateur Extra Class Examination Manual Ninth Edition (2011).
His discussion further validated that soil permeability and a good ground system are likely to improve quarter wavelength vertical antenna efficiency. Imagine, without even realizing and without factoring in variables, my overall vertical performance may not exceed that of 50% efficiency. Ouch!
In the meantime, Micro dB Theory would then ask me to account for efficiency, as "total" load of the antenna system including transmission line linking antenna with transceiver and radiation resistance. I need to factor variables like nearby objects and height above ground as well.
Perhaps, one micro-iteration to consider is looking at one's conductor that is its length and diameter including nearby objects as potentially changeable?
73 from the shackadelic near the beach.
Image may be NSFW.Is there a relationship between antenna radiation resistance and Micro dB Theory? What is antenna efficiency and its relationship if any to the same theory?
Silver (2011) stated, supplied energy to one's antenna is dissipated either as a radio wave or as heat in the wire additionally; nearby objects such as fencing; a brick; or shrubbery will absorb the same energy.
Certainly, when considering micro-iteration at one's antenna system, maximizing energy as a radio wave is inherently better than lost heat in the wire.
Two types of resistances are accounted for in one's antenna system, according the author; that is radiated power and the other is heat as a function of loss. Ideally, one wants effective radiated power over that of power lost as heat and Silver described heat resistance (R) as real or ohmic (2011).
The second accounting of (R) is theoretical or assumed resistance, if present; it dissipates the power radiated by one's antenna system (2011). Theoretical or assumed power is referenced as radiation resistance.
Ohmic resistance physically debits one's antenna system as a function of heat. However, theoretical or assumed radiation, is an antenna system construction credit. Silver explained it this way, "It is reasonable to assume that the ohmic (heat) loss in a reasonably located antenna is negligible and that all of the resistance shown by the antenna is radiation resistance" (p 9.5, 2011).
Antenna efficiency is a function of radiation resistance divided by total resistance multiplied by 100% according to Silver (2011). As radiation resistance decreases then ohmic (heat) resistance or antenna loss increases as a function of heat. The following variables, according to the author (2011), should be factored into antenna deployment and construction; location of objects near the antenna with emphasis on earth, and the length and diameter ratio of chosen conductor.
Lastly, I recommend reading further about antenna efficiency, because Silver discussed the effect of height and ground on that of a quarter wavelength vertical antenna system, on page 9-6 of the Amateur Extra Class Examination Manual Ninth Edition (2011).
His discussion further validated that soil permeability and a good ground system are likely to improve quarter wavelength vertical antenna efficiency. Imagine, without even realizing and without factoring in variables, my overall vertical performance may not exceed that of 50% efficiency. Ouch!
In the meantime, Micro dB Theory would then ask me to account for efficiency, as "total" load of the antenna system including transmission line linking antenna with transceiver and radiation resistance. I need to factor variables like nearby objects and height above ground as well.
Perhaps, one micro-iteration to consider is looking at one's conductor that is its length and diameter including nearby objects as potentially changeable?
73 from the shackadelic near the beach.
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