On Tue, 05 Dec 2006 03:55:50 GMT, "Jerry Martes"
wrote:

I have been trying to understand how it can be
determined that Yagiis are inefficient.

Hi Jerry,

That, in fact, is quite very simple.

Allow that every living person on this planet (arbitrarily assign that
number to be 6 Billion) has a receiver that is receiving you with arm
chair copy (arbitrarily assign that to be 10dB over S-9) to your
signal (arbitrarily assign that to be 100W) applied to your antenna
(arbitrarily assumed to be a Yagi).

What is the Yagi efficiency?

S-9 is 50µV into 50 Ohms and through various mental gymnastics we can
pin that down to being 50 picoWatts - but wait! There's 10dB more!
call it ½ nanoWatt....

Aggregate that over the entire Earth's total population eagerly
awaiting the news of your power efficiency. 3W total absorption. 3%
efficient.

Now, try something simple like raising that efficiency one notch, and
still hitting ALL 6 Billion people.

Hint, the Yagi couldn't satisfy this in the first place because of a
property called directivity, so a design that is "more efficient" is
even more mythical ;-)

I dare say no one here can prove to be 0.001% efficient in these
terms. [Must be validated through QSL cards.]

Efficiency: Can't live with it; Can't live without it!

73's
Richard Clark, KB7QHC

"Richard Clark" wrote in message
...
On Tue, 05 Dec 2006 03:55:50 GMT, "Jerry Martes"
wrote:

I have been trying to understand how it can be
determined that Yagiis are inefficient.

Hi Jerry,

That, in fact, is quite very simple.

Allow that every living person on this planet (arbitrarily assign that
number to be 6 Billion) has a receiver that is receiving you with arm
chair copy (arbitrarily assign that to be 10dB over S-9) to your
signal (arbitrarily assign that to be 100W) applied to your antenna
(arbitrarily assumed to be a Yagi).

What is the Yagi efficiency?

S-9 is 50µV into 50 Ohms and through various mental gymnastics we can
pin that down to being 50 picoWatts - but wait! There's 10dB more!
call it ½ nanoWatt....

Aggregate that over the entire Earth's total population eagerly
awaiting the news of your power efficiency. 3W total absorption. 3%
efficient.

Now, try something simple like raising that efficiency one notch, and
still hitting ALL 6 Billion people.

Hint, the Yagi couldn't satisfy this in the first place because of a
property called directivity, so a design that is "more efficient" is
even more mythical ;-)

I dare say no one here can prove to be 0.001% efficient in these
terms. [Must be validated through QSL cards.]

Efficiency: Can't live with it; Can't live without it!

73's
Richard Clark, KB7QHC

Hi Richard

All kidding aside, I have actually learned things thru this thread. I had
previously considered Efficiency to be a term applied to I squared R losses.
Sure, I know about Aperture Efficiency, but I never knew about Beam
Efficiency till someone presented a reference to a site mentioning it.

But, if that previous thread referred to a Yagi as being inefficient due
to its I squared R losses, I want to see the data supporting that claim.

Incidentally, Pico Blvd doesnt go thru Watts

Wow, this thread has gone way past my minute understanding of charges
and fields.. I'm always amazed everytime a refrigerator magnet
sticks... Where is Dick Feinman when I need him to explain all
this...
As far as I can tell Art, you intend to load up a balloon until it
bursts... That's gotta be hard on the amp when it goes...

denny / k8do

Denny wrote:
Wow, this thread has gone way past my minute understanding of charges
and fields.. I'm always amazed everytime a refrigerator magnet
sticks... Where is Dick Feinman when I need him to explain all
this...

You can purchase and download a lot of his physics lectures as pod casts
from Apple's Itunes.

- Galen, W8LNA

On Tue, 05 Dec 2006 06:56:40 GMT, "Jerry Martes"
wrote:

But, if that previous thread referred to a Yagi as being inefficient due
to its I squared R losses, I want to see the data supporting that claim.

Hi Jerry,

You may as well abandon that expectation and everything related to it.

Incidentally, Pico Blvd doesnt go thru Watts

Does it cross de Gallo?

73's
Richard Clark, KB7QHC