Thread: Yagi efficiency
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Old December 4th 06, 12:50 PM posted to rec.radio.amateur.antenna
Denny Denny is offline
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First recorded activity by RadioBanter: Jul 2006
Posts: 326
Default Yagi efficiency

Jerry, if I came across a bit loud I apologize.. I usually skim down
the latest chatter and then just post to the group off the bottom
message, often having no direct bearing on the particular post it spins
off from... Also, I skim a number of groups and topics and I run a
business so I can miss a post that puts a different spin on things...
If I ruffled your feathers it was not intentional...
Let me comment that I absolutely agree with you that claiming a Yagi is
inefficient from the perspective of I2R losses shows a lack of basic
knowledge... Having said that, let me also note that closing the
spacing, i.e. tighter than the classical Yagi-Uda array, and putting
the beam into Supergain territory has consequences... Moxon has a non
mathematical discussion of the supergain antennas with a graph of
spacing v/s gain v/s impedence, and I Krauss mentioned that he designed
his flat top array stimulated from a paper by Brown (I think it was)
where he discussed arrays that have more than additive gain by tight
spacing... Anyway I digress; the point of all this mumble is that these
supergain "Yagi" arrays can have quite high I2R losses... But the
commercial Yagi-Uda today is not in that class...

Anyway, Cheers ... denny / k8do