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"Perfect resonance and flat SWR will provide greatest Effective Radiated Power".

not so. an antenna exhibiting a radiation resistance of 14 ohms and total loss resistance of 36 ohms will perform poorly when compared to another antenna exibiting a radiation resistance of 36 ohms and total loss resistance of 14 ohms.

it's no mystery here that they both add up to 50 ohms and swr is 1.0:1 for both antennas. even though the total resistance of both antennas is 50 ohms, the radiation efficiency of the first antenna will be only 28% while the radiation efficiency of the second antenna will be 72%. assuming no line loss to keep it simple, the first antenna will radiate 28W. and the second antenna will radiate 72W with 100W input in both cases. the difference in directivity between them is 4.1 dB..

"Low SWR does not tell us anything about how well the antenna is working. (antenna efficiency) Bob got that right.

<blockquote data-quote="freecell" data-source="post: 776100" data-attributes="member: 30">&quot;Perfect resonance and flat SWR will provide greatest Effective Radiated Power&quot;.not so. an antenna exhibiting a radiation resistance of 14 ohms and total loss resistance of 36 ohms will perform poorly when compared to another antenna exibiting a radiation resistance of 36 ohms and total loss resistance of 14 ohms.it&#039;s no mystery here that they both add up to 50 ohms and swr is 1.0:1 for both antennas. even though the total resistance of both antennas is 50 ohms, the radiation efficiency of the first antenna will be only 28% while the radiation efficiency of the second antenna will be 72%. assuming no line loss to keep it simple, the first antenna will radiate 28W. and the second antenna will radiate 72W with 100W input in both cases. the difference in directivity between them is 4.1 dB.. &quot;Low SWR does not tell us anything about how well the antenna is working. (antenna efficiency) Bob got that right.</blockquote>

[QUOTE="freecell, post: 776100, member: 30"] "Perfect resonance and flat SWR will provide greatest Effective Radiated Power". not so. an antenna exhibiting a radiation resistance of 14 ohms and total loss resistance of 36 ohms will perform poorly when compared to another antenna exibiting a radiation resistance of 36 ohms and total loss resistance of 14 ohms. it's no mystery here that they both add up to 50 ohms and swr is 1.0:1 for both antennas. even though the total resistance of both antennas is 50 ohms, the radiation efficiency of the first antenna will be only 28% while the radiation efficiency of the second antenna will be 72%. assuming no line loss to keep it simple, the first antenna will radiate 28W. and the second antenna will radiate 72W with 100W input in both cases. the difference in directivity between them is 4.1 dB.. "Low SWR does not tell us anything about how well the antenna is working. (antenna efficiency) Bob got that right. [/QUOTE]

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