"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 3/26/2016 4:20 AM, Ian Jackson wrote:
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.

Sometimes that is worse than the original, improves contrast, but horrid
to read still. It does nothing for the shadowed text. That one is
truly bizarre. I think it is a "style" thing. They are trying to be
trendy.

--

Rick

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

On 3/26/2016 1:14 PM, Jeff Liebermann wrote:
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

The datasheet for the NanoStationlocoM9 which seems to be the newer
version of what I have has a return loss graph for the internal antenna.
This seems to show a range centered on about 917 MHz and not too wide.
It says the frequencies used are 902 to 928 MHz.

I looked at the highest gain antennas from each of these two and neither
supplies VSWR graphs. The Laird PC9013N has 13 elements and says freq
range is 902 to 928 MHz which seems to roughly match the internal antenna.

The L-com model HG914YE with 14 elements says it works from 824 to 960
MHz. It claims a 1.5:1 VSWR "average" which I guess means something,
but I'm not sure what. This unit has 14 dBi of gain while the Laird is
13 dBi. I'm thinking 1 dB is not so much. The Laird seems to be well
over $100 and the L-com around $50 with free shipping. I'll also need
an N to SMA pigtail. First I need to ask my provider. He may have to
twiddle something in the box to enable the antenna input.

BTW, one of these antennas says the directors are welded to the boom. I
always thought the elements were insulated from each other and the boom.
I recall seeing insulation on old TV antennas, was that just to
prevent corrosion or something?

--

Rick

On Sat, 26 Mar 2016 14:08:12 -0400, rickman wrote:

The datasheet for the NanoStationlocoM9 which seems to be the newer
version of what I have has a return loss graph for the internal antenna.
This seems to show a range centered on about 917 MHz and not too wide.
It says the frequencies used are 902 to 928 MHz.

Unless Ubiquiti is doing something odd, if they use FHSS (frequency
hopping spread spectrum), the radio must hop all 83 channels (in 1 MHz
increments) within some interval that I'm too lazy to excavate from
FCC Part 15. In effect, you'll see it hop the entire allocated
frequency range.

One source of confusion is whether an antenna has to TUNE over a
frequency range, or whether it has to OPERATE over a frequency range.
It's possible to find a narrow band FM 900 MHz antenna that will tune
the desired range, but once tuned, has a much smaller operating
bandwidth. High gain Yagi and big gain patch/panel antennas are
potential problems.

I looked at the highest gain antennas from each of these two and neither
supplies VSWR graphs. The Laird PC9013N has 13 elements and says freq
range is 902 to 928 MHz which seems to roughly match the internal antenna.

The L-com model HG914YE with 14 elements says it works from 824 to 960
MHz. It claims a 1.5:1 VSWR "average" which I guess means something,
but I'm not sure what.

Average is not the usual term. I would have no problem with 1.5:1
maximum VSWR, but average sounds like they're hiding a problem.

This unit has 14 dBi of gain while the Laird is
13 dBi.

Many of the gain plots are simulations and are not the result of field
tests or anechoic chamber tests. It's fairly easy to recognize the
difference. The real tests show lower numbers and look far from idea.
The simulations look too good.

I'm thinking 1 dB is not so much. The Laird seems to be well
over $100 and the L-com around $50 with free shipping. I'll also need
an N to SMA pigtail. First I need to ask my provider. He may have to
twiddle something in the box to enable the antenna input.

Ask your WISP what kind of antenna he recommends. I doubt that this
is the first higher gain antenna that he's installed.

I still recommend using a panel antenna. I have a few in the office,
but they're circular polarization for near field devices and probably
won't work for you. Start he
https://www.google.com/#q=900+mhz+panel+antenna
Anything over about 10dBi gain should be sufficient.

BTW, one of these antennas says the directors are welded to the boom.

Yes. Good idea if you want it to survive. All of the Laird (Antenex)
Yagi's that I've used were welded and had rounded ends to improve the
bandwidth. They're more expensive than bolt together Yagi's but I
think it's worth it for mountain top use, where I have to pay an
expensive certified tower climber to deal with any damage. However,
for the average consumer, it's probably overkill.

I always thought the elements were insulated from each other and the boom.
I recall seeing insulation on old TV antennas, was that just to
prevent corrosion or something?

No. It makes the TV antenna easy to ship in a smaller box. If TV
antennas were welded and shipped ready to install, they would be huge,
and the shipping would be seriously expensive.

The elements of a Yagi do not need to insulated from the boom.
However, the length of the elements is affected by the boom. The RF
path goes around the boom in the welded design requiring 1/2 the
circumference of the boom to be added to the element length
calculation.

--
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 1:14 PM, Jeff Liebermann wrote:
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 just gave this a try. It completely changes the page formatting. It
doesn't seem to work with just any page. Not sure about the
capabilities, I'll have to play with it. Thanks

--

Rick