"Jeff" wrote in message ...


I think we refer to "beam antennas" that way because they behave like
lamps with reflectors, directing a beam of RF like a beam of light. I
don’t know the historical accuracy of my thinking.



I think from a historical perspective the name derives from 'Beam
Stations' such as those comprised in the Imperial Wireless Chain. That
is stations that were set up to 'beam' their signals to far flung places
on the globe.

Antennas were not what would be described as beam antennas these days
but were types such as curtain arrays.
================================================== ===========

I can understand that. Thanks.

I think "beam" i spolitical name. Antenas with directivity was made by
japanese scientists Yagi and Uda. And after WWII Japan was not very popular
between Americans. So, they name such antennas "beam"



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Sorry for my bad english. Not between americans, among Americans. In
Croatian we use the same word for both terms



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Wor wrote:
I think "beam" i spolitical name. Antenas with directivity was made by
japanese scientists Yagi and Uda. And after WWII Japan was not very popular
between Americans. So, they name such antennas "beam"

Except Yagi and Uda did their work well before WWII.

The term "beam" is nothing more than slang for a directional device.


--
Jim Pennino

"Wor" wrote in message ...

I think "beam" i spolitical name. Antenas with directivity was made by
japanese scientists Yagi and Uda. And after WWII Japan was not very popular
between Americans. So, they name such antennas "beam"

I don't know the correct definition, but my definition is an antenna array
with inline elements.
Those elements can be parasitic or driven. And they can be dipoles, quads,
triangles or whatever.

"Wayne" wrote in message ...



"Wor" wrote in message ...

I think "beam" i spolitical name. Antenas with directivity was made by
japanese scientists Yagi and Uda. And after WWII Japan was not very popular
between Americans. So, they name such antennas "beam"

I don't know the correct definition, but my definition is an antenna array
with inline elements.
Those elements can be parasitic or driven. And they can be dipoles, quads,
triangles or whatever.
================================================== ==
I beginning to get the sense that the definition is sufficiently broad that
the antenna in question has to be described in more detail if the term
"beam" is to be applied.

"Sal"

On Fri, 25 Mar 2016 21:24:45 -0700, "Sal M. O'Nella"
wrote:

I don't know the correct definition, but my definition is an antenna array
with inline elements.
Those elements can be parasitic or driven. And they can be dipoles, quads,
triangles or whatever.

My definition of an antenna is a matching transformer which matched
the output impedance of a transmitter, with that of free space (377
ohms). Convention has it to name the antenna after the designer. In
this case, Shintaro Uda was the student assistant who designed the
antenna, while Hidetsugu Yagi was his university instructor. Uda
published a paper on the design in Japanese, which nobody seemed to
have noticed. A few years later, Yagi translated the paper into
English, which finally got some attention. Its publication resulted
in the antenna being called a Yagi antenna by the American press. Yagi
repeatedly reminded everyone that it was Uda who had designed the
antenna, and deserved the credit. However, the best that could be
done was the Yagi-Uda contraction, which is awkward and backwards.

http://what-is-what.com/what_is/Yagi_Uda_antenna.html
"Despite the fact that Hidetsugu Yagi never took credit for
the antenna's design, it was his name that the American press
used to refer to the concept."

http://www.radiocomms.com.au/content/industry/article/yagi-the-man-behind-the-antenna-647231587
"The technology is all down to Prof Hidetsugu Yagi and his
assistant Shintaro Uda; more to Uda than Yagi, in fact, so
strictly speaking the design should be known as the Uda antenna,
or at least Yagi-Uda."

Incidentally, I have an FM broadcast Yagi-Uda antenna on my roof that
was made by the Yagi-Uda Antenna Company (or something like that).
I'll see if I can find the documentation and post a copy.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On 3/26/2016 12:53 AM, Jeff Liebermann wrote:
On Fri, 25 Mar 2016 21:24:45 -0700, "Sal M. O'Nella"
wrote:

I don't know the correct definition, but my definition is an antenna array
with inline elements.
Those elements can be parasitic or driven. And they can be dipoles, quads,
triangles or whatever.

My definition of an antenna is a matching transformer which matched
the output impedance of a transmitter, with that of free space (377
ohms). Convention has it to name the antenna after the designer. In
this case, Shintaro Uda was the student assistant who designed the
antenna, while Hidetsugu Yagi was his university instructor. Uda
published a paper on the design in Japanese, which nobody seemed to
have noticed. A few years later, Yagi translated the paper into
English, which finally got some attention. Its publication resulted
in the antenna being called a Yagi antenna by the American press. Yagi
repeatedly reminded everyone that it was Uda who had designed the
antenna, and deserved the credit. However, the best that could be
done was the Yagi-Uda contraction, which is awkward and backwards.

http://what-is-what.com/what_is/Yagi_Uda_antenna.html
"Despite the fact that Hidetsugu Yagi never took credit for
the antenna's design, it was his name that the American press
used to refer to the concept."

http://www.radiocomms.com.au/content/industry/article/yagi-the-man-behind-the-antenna-647231587
"The technology is all down to Prof Hidetsugu Yagi and his
assistant Shintaro Uda; more to Uda than Yagi, in fact, so
strictly speaking the design should be known as the Uda antenna,
or at least Yagi-Uda."

Incidentally, I have an FM broadcast Yagi-Uda antenna on my roof that
was made by the Yagi-Uda Antenna Company (or something like that).
I'll see if I can find the documentation and post a copy.

Both of these pages were interesting, but hard to read. I don't get why
some pages use a light grey text. I suppose some don't have a problem
reading that, but I do, a *lot*. The other page intentionally added a
shadow to the text, not just the headings or links, making that page
even harder for me to read. I really don't get that either.

I found a few more pages on Yagi-Uda antennas and some derivatives. One
describes how to build a Quagi antenna where the driven element and the
reflector are loops. Seems that works pretty well getting similar
numbers to Yagi type antennas with more directors.

What I really need in an antenna, is something I can add to the ubiquiti
nanostation m900 loco I am using for Internet access. The internal
antenna is only 7.5 dBi. I see a Yagi which is 13 dBi but it seems to
be out of date. The current model is very fancy and is over $200. The
other one is only $33.

--

Rick

In message , rickman
writes



Both of these pages were interesting, but hard to read. I don't get
why some pages use a light grey text. I suppose some don't have a
problem reading that, but I do, a *lot*.

+1

It's plain stupid. Perhaps they think that they are saving 'ink'! A
quick fix is to highlight the offending text.




--
Ian

On Sat, 26 Mar 2016 02:17:21 -0400, rickman wrote:

Both of these pages were interesting, but hard to read. I don't get why
some pages use a light grey text. I suppose some don't have a problem
reading that, but I do, a *lot*. The other page intentionally added a
shadow to the text, not just the headings or links, making that page
even harder for me to read. I really don't get that either.

If you're using Firefox, click on the "reader view" icon.
https://support.mozilla.org/en-US/kb/firefox-reader-view-clutter-free-web-pages
There are similar features and plug-ins for other browsers.

I see all too much of the "gray text" problem that inspired such
things as "reader view". I agree, it sucks. It's the result of some
of the really bad style sheets that are found in many CMS (content
management system) web page creations. It's main benefit is that it
emphasizes the advertising. It also holds your attention longer so
that you stay on the web page longer. I can bore you with details on
how this works in advertising if you're interested.

I found a few more pages on Yagi-Uda antennas and some derivatives. One
describes how to build a Quagi antenna where the driven element and the
reflector are loops. Seems that works pretty well getting similar
numbers to Yagi type antennas with more directors.

Yep. A quagi is a square loop element. The big advantage of quagi
and loop yagi antennas is that they squeeze a few more dB of gain
(about 2-3dB) with the same boom length as a conventional yagi. That's
not a trivial amount when you consider that in order to get 3dB more
gain out of a yagi, the boom has to be twice as long.

What I really need in an antenna, is something I can add to the ubiquiti
nanostation m900 loco I am using for Internet access. The internal
antenna is only 7.5 dBi. I see a Yagi which is 13 dBi but it seems to
be out of date. The current model is very fancy and is over $200. The
other one is only $33.

I'm involved with a bunch of 900 MHz ham radio repeaters and had a
fair amount of experience with 900 MHz. I don't like yagi antennas
for 900 or 2.4GHz. I prefer patch or panel antennas. However, if you
must buy a yagi, I suggest something by Antennex or something resold
by Laird. By the time you get to 13 or 14dBi gain, the bandwidth of a
yagi becomes sufficiently narrow that you'll loose gain at the band
edges. Since your radio needs to hop from 902-928Mhz, you'll need an
antenna that's fairly flat across the entire range. Just keep your
eye on the VSWR vs Freq graphs to avoid this problem.
http://www.lairdtech.com/product-categories/antennas/yagis
http://www.l-com.com/wireless-antenna-900-mhz-yagi-antennas

Gotta run...
--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558