Jerry Martes wrote:
Hi Denny

The fact is, I probably get "ruffled" too easily, probably because I'm
insecure. I'm not the sharpest antenna designer around.
My way of antenna design relies mainly on actual, measured data, so I am a
little short on convincing theoretical data. But, my approach to
determining relative efficiency would be based on measured data.
If *I* had made any statement on the efficiency of *any* antenna, you can
be sure I would include some measured data. Measuring Yagi antenna loss is
probably too mundane for Art. He already knows things that would require me
months of testing to 'check up on'.
If I wanted to know the "I squared R loss" efficiency of one antenna
compared to another antenna, I'd need to conduct time consuming experiments.

Jerry






"Denny" wrote in message
s.com...
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




Jerry:

I didn't really disagree with you, ALL antennas are 100% efficient
radiators (dummy loads are excellent too!), only a real fool would argue
that one!

But this is california, I don't need the infrared radiations all that
much; never had trouble with ice sickles on the 'tenna. grin.

Warmest regards,
JS