Thread: Yagi efficiency
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Old December 4th 06, 12:23 AM posted to rec.radio.amateur.antenna
art art is offline
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First recorded activity by RadioBanter: Sep 2006
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Default Yagi efficiency

More current is not necessarily used for reradiation .
You also have circulating current because of inherrant
inductance and capacitance since we are dealing with a series
circuit. You can add resistance to the circuit when you are at
some distance from resonance which is similar to forming band
pass shapes but the bottom line is that at resonance or near
resonance pure resistance rules To get closer to what is really
happening is to go back to 455 khz when used in radio
circuits to revive the memory
Art


Cecil Moore wrote:
art wrote:
Cecil Moore wrote:
Actually Art, adding reactance reduces the current in
the element thus *decreasing* losses below what a resonant
passive element would have. Pure reactance is lossless.


This current that you are referring to, I used P =I squared R
which leads to lower power. Where did I go wrong


Lower power results in lowering the loss due to heat.
That leaves more power available to be radiated by
the antenna system but not necessarily radiated by
this single element that we are discussing. I suspect
two driven elements are theoretically capable of
better performance than a two element Yagi given
equal total power input into the elements.
--
73, Cecil http://www.w5dxp.com