Wi-Fi antenna brands/quality/reviews

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Hello.

I've been searching around for awhile now, trying to find some good
information about antennas and have come up with pretty much nothing.

I've noticed there are a lot of places selling antennas for 802.11 systems
and the prices vary widely. Most seem to have similar or identical
specifications, yet the "same" item can range in price from about $20 to
$200.

For example, the following patch antennas have very similar characteristics
but different prices:

Cisco AIR-ANT3549 Patch antenna: $137.00 (www.infinity-micro.com)
Hyperlink  HG2409P Patch antenna: $24.95 (www.hyperlinktech.com)

Some of the other places I've looked include: WinnCom (www.winncom.com),
Connectronics (www.connectronics.com), Wi-Fi Plus (www.wifi-plus), Symbol,
Cisco, Hawking (www.hawkingtech.com), Andrew (www.andrew.com), 3Com, Telex,
and many more...

So here is my question: Has anyone seen any *real* information or had any
experience with antenna manufacturers/distributors? I'm willing to pay more
for quality, but I can't seem to determine which products are actually good
and which are just "expensive".

Thanks!

Steve



Re: Wi-Fi antenna brands/quality/reviews


all of these antennas cost about 5 $ to build by hand.
they all based on the same concept.
just make your own there are plenty of how tos with pics online.
dont waste your money
>
> Hello.
>
> I've been searching around for awhile now, trying to find some good
> information about antennas and have come up with pretty much nothing.
>
> I've noticed there are a lot of places selling antennas for 802.11 systems
> and the prices vary widely. Most seem to have similar or identical
> specifications, yet the "same" item can range in price from about $20 to
> $200.
>
> For example, the following patch antennas have very similar
> characteristics but different prices:
>
> Cisco AIR-ANT3549 Patch antenna: $137.00 (www.infinity-micro.com)
> Hyperlink  HG2409P Patch antenna: $24.95 (www.hyperlinktech.com)
>
> Some of the other places I've looked include: WinnCom (www.winncom.com),
> Connectronics (www.connectronics.com), Wi-Fi Plus (www.wifi-plus), Symbol,
> Cisco, Hawking (www.hawkingtech.com), Andrew (www.andrew.com), 3Com,
> Telex, and many more...
>
> So here is my question: Has anyone seen any *real* information or had any
> experience with antenna manufacturers/distributors? I'm willing to pay
> more for quality, but I can't seem to determine which products are
> actually good and which are just "expensive".
>
> Thanks!
>
> Steve
>
>




Re: Wi-Fi antenna brands/quality/reviews


I'm new to all this

can one just "buy" a wifi antenna say for car use?

If yes... what do you recommend?


Re: Wi-Fi antenna brands/quality/reviews


me@privacy.net wrote:
> I'm new to all this

> can one just "buy" a wifi antenna say for car use?

There are certainly some commercial mag-mount antennas intended for
automotive use.  http://www.fab-corp.com/ click on "antennas omni" on the
left.  The little 5.5dBi mag mount has too thin of a cable, so you don't
really get 5.5 dBi from it, but it's cheap, if you have a card that accepts
an external antenna.  Inside the car, you could use any of the indoor
antennas.  The ones intended for client use usually have little desk
stands.

You might be intrigued by making your own.
http://www.lincomatic.com/wireless/homebrewant.html
The patch panel is probably the cleanest design.
http://www.lincomatic.com/wireless/wifipatchantenna.html

Patches are directional enough to provide some good gain toward where you
are driving, if mounted correctly, and wide enough to just point in the
general direction.  I assume you are thinking of something like parking in
front of a Starbucks while using your T-Mobile connection.

A USB adapter, either mini or full size, allows you to put the radio and
antenna in a better location than a card plugged into your laptop.
That eliminates the need for a card with an external connector.

I suppose you could mag mount one to the roof of the car...  I'll let Jeff
model the reflections for that one ;-)

The USB mini that I have is a DWL-122.  I just hang the USB cable over the
rearview mirror for a view out the front of the car.  Sometimes I stick it
in a coffee can for improved range.
http://www.dlink.com/products/?sec=0&pid=334 That's a "g",  My "b" seems
to have disappeared from the web site.  The "b" were pretty cheap, down
around $10.
Mine, stuck in a coffee can:
http://www.rahul.net/dold/clarence/usb-can/im000742-800x600.jpg

There are combination USB radio with antenna from Hawking and others.
http://www.hawkingtech.com/prodSpec.php?ProdID=208

--
---
Clarence A Dold - Hidden Valley (Lake County) CA USA  38.8,-122.5



Re: Wi-Fi antenna brands/quality/reviews


On Mon, 25 Apr 2005 16:56:37 +0000 (UTC),
dold@XReXXWi-Fi.usenet.us.com wrote:

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Just a minor note.  The Bi-Quad construction details on the above web
page are totally wrong and will not work.

Quoted text here. Click to load it

Retch.  The spaceing between the aluminium foil and the patch element
is fairly critical.  There's no way to get it right (unless you wanna
play cut-n-try) on the spacing using a non-flat base and foil.  The
base reflector also needs to be somewhat larger than the patch (about
twice diameter) to be effective reflector and not radiate backwards.
  

Quoted text here. Click to load it

I was using a patch antenna for war driving for a while.  Suction cups
on the back held it to my right window.  I would get the access points
on one side of the road on the way to work, and the other side on the
way back.  However, the size of the cable was always a problem.  I had
a short pigtail of RG-174 coax to go through the window or door, a big
fat piece of LMR400 to make it to my laptop, and another piece of
RG-174 for a pigtail.  Far too many connectors and very awkward.  So,
I switched to a rooftop USB radio which works much better.

Quoted text here. Click to load it

Yep.  However, I still managed to mangle the USB connector on my
laptop.  I've replaced it twice so far.  I found a right angle USB
connector which has survived the last month or so without breaking.

Quoted text here. Click to load it

Been there, don't bother.  The losses in the typical NMO antenna mount
are horrendous.  I'm working on a rotating magnet mount panel antenna
which I plan to use for moving direction finding.  Kinda like the
rotating red lights on a police vehicle.  It would also be useful on a
mobile home for aiming at the local hot spot.


--
Jeff Liebermann    jeffl@comix.santa-cruz.ca.us
150 Felker St #D   http://www.LearnByDestroying.com
Santa Cruz CA 95060    AE6KS  831-336-2558

Re: Wi-Fi antenna brands/quality/reviews


> On Mon, 25 Apr 2005 16:56:37 +0000 (UTC),
> dold@XReXXWi-Fi.usenet.us.com wrote:

>>You might be intrigued by making your own.
>>http://www.lincomatic.com/wireless/homebrewant.html

> Just a minor note.  The Bi-Quad construction details on the above web
> page are totally wrong and will not work.

I think the totally wrong directions were corrected a long time ago.  
It still says and shows "Instead of rigid coax as specified by Trevor, I
just used some more copper wire for the connections" which might be wrong,
but I think "totally" is a little far.  Trevor's pictures are horrible, and
I can't see the proper coax connection, nor a description of it.
http://martybugs.net/wireless/biquad/ mentions the fault with Trevor's
site, and has better instructions and pictures.

>>The patch panel is probably the cleanest design.
>>http://www.lincomatic.com/wireless/wifipatchantenna.html

> Retch.  The spaceing between the aluminium foil and the patch element

I didn't see any aluminum foil on that page.

> is fairly critical.  There's no way to get it right (unless you wanna
> play cut-n-try) on the spacing using a non-flat base and foil.  The
> base reflector also needs to be somewhat larger than the patch (about
> twice diameter) to be effective reflector and not radiate backwards.

The dimensions are stolen from some commercial antenna, although the
reflector does look smaller than on the original page.

> Yep.  However, I still managed to mangle the USB connector on my
> laptop.  I've replaced it twice so far.  I found a right angle USB
> connector which has survived the last month or so without breaking.

You need a Mini-USB hub, semi-permanently attached.  

--
---
Clarence A Dold - Hidden Valley (Lake County) CA USA  38.8,-122.5



Re: Wi-Fi antenna brands/quality/reviews


On Tue, 26 Apr 2005 00:00:14 +0000 (UTC),
dold@XReXXWi-Fi.usenet.us.com wrote:

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The biquad shown near the bottom of the page on the Lincomatic web
page has the coax stop at the reflector and has an unshielded wire
going between the reflector and the biquad.  This is totally wront.
The shield must extend all the way to the biquad elements.

Quoted text here. Click to load it

Look again.  The bottom of the plastic food container is lined with
aluminium foil as a reflector.  Upper left photo in the group of 4
photos.

Quoted text here. Click to load it

Yep.  It's too small to be totally effective.  There will be some
leakage from the patch element toward the rear.  Rule-o-thumb is that
the reflector diameter should be about twice the diameter of the
patch.  The exact dimensions of the reflector are not terribly
critical.  I can model it both ways using mstrip40
  http://www.e-technik.fh-kiel.de/~splitt/html/mstrip.htm
but I'm still learning the program and am having problems.

Quoted text here. Click to load it

Naw.  Radio Shock sells a flexible hinged USB adapter designed for the
purpose.  I can have the USB connector be flush against the laptop
which also reduces breakage issues.



--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831.336.2558 voice  http://www.LearnByDestroying.com
#                         jeffl@comix.santa-cruz.ca.us
#                           jeffl@cruzio.com     AE6KS

Re: Wi-Fi antenna brands/quality/reviews



> Look again.  The bottom of the plastic food container is lined with
> aluminium foil as a reflector.  Upper left photo in the group of 4
> photos.

Nah, it's your favorite skin effect material "piece of scrap galvanized
steel".  It does look vaguely like it is bent at the edges to fit in the
Tupperware thingie.  Okay.  I'll never reference Lincomatic again.
The open air (300ohm?) portion of the feed in the biquad is kinda ugly.

> Yep.  It's too small to be totally effective.  There will be some
> leakage from the patch element toward the rear.  

They just stole the commercial design of
http://devices.planet-wireless.de/comtelco/comtelco5.jpg
That shows the reflector as 90mm diameter, and the patch at 46x50.
They should have stolen a better design?

--
---
Clarence A Dold - Hidden Valley (Lake County) CA USA  38.8,-122.5



Re: Wi-Fi antenna brands/quality/reviews


On Tue, 26 Apr 2005 04:06:27 +0000 (UTC),
dold@XReXXWi-Fi.usenet.us.com wrote:


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Yuck.  Horrible surface losses.  Magnetic materials are always a
problem at microwave frequencies.  Antennas should be made from
copper, brass, aluminium, and non-magnetic stainless.  Not steel.  It
still looks like aluminium foil to me, but I guess I must be going
blind.  Maybe I'll read the text.

Quoted text here. Click to load it

Some of the other stuff is just fine.  I only object to Biquad
construction.

Quoted text here. Click to load it

No where near 300 ohms.  Ugly is ok.  Actually, the uglier the
antenna, the better it works.  However, in this case, the extra
exposed wires act as inductors and block much of the signal.

Quoted text here. Click to load it

I bought several Comtelco antennas and installed them at customer
locations.  They worked acceptably well.  I never did understand how
that antenna is suppose to work.

Some other examples to plagerize.
|  http://www.rc-cam.com/gp_patch.htm
Note that this is a circularly polarized patch and not a linearly
(vertical or horizontal) polarized patch.  It will work with vertical
polarization but with 3dB polarization mismatch loss.  The amount cut
at the corners isn't enough to be fully circularly polarized, so the
polarization mismatch loss will be less than 3dB.

Here's some more circularly polarized designs:
|  http://members.aol.com/k5oe/DualPatch/dual_patch.htm
|  http://homepages.ihug.co.nz/~jpsl/a_simple_patch_antenna_feed.htm
|  http://www.qsl.net/k3tz/k3tz.html
|  http://www.qsl.net/k3tz/7n1jvw.html
Note the large reflector, the location of the feed point, and the
materials used.  Note that these are optimized for the lower part of
the 2.4Ghz band as used for ham radio, and will need to be tweaked for
the ISM band.


--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831.336.2558 voice  http://www.LearnByDestroying.com
#                         jeffl@comix.santa-cruz.ca.us
#                           jeffl@cruzio.com     AE6KS

Re: Wi-Fi antenna brands/quality/reviews


Quoted text here. Click to load it


You don't like the biquad, you don't like the patch.  The soup cans can be
found in many places.

Quoted text here. Click to load it

Using your favorite material again.  The shopping list includes "Galvanized
Step Flashing."  The size of the reflector is 106mm.  The driven element is
56mm.  The Lincomatic has a 90mm reflector and 50mm element.
I don't see where your comments about the reflector being way too small are
borne out by any of the pages you referenced.

Quoted text here. Click to load it

I just don't see the "large" reflector.  Most of them seem to reference the
identical drawing, except for the goof-proof.  But he uses wood for
spacers, which I wouldn't think would be wise.  Wood strikes me as a
variable semi-conductor, depending on humidity and condition.

Where are your patches?
You refer to them often, but I've never seen one exposed.

My next victim is back from Japan, so I'm going to be setting up something
in the next week or two, maybe a USB dongle in a can, maybe a game adapter,
maybe a long cable to a patch antenna.  

--
---
Clarence A Dold - Hidden Valley (Lake County) CA USA  38.8,-122.5


Re: Wi-Fi antenna brands/quality/reviews


On Tue, 26 Apr 2005 17:39:19 +0000 (UTC),
dold@XReXXWi-Fi.usenet.us.com wrote:

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Not exactly.  I really like Trevor's Biquad design.  What I didn't
like was the way Lincomatic built the biquad.  I also like patch
antennas very much.  What I don't like is making them for sheet steel,
galvanized roofing flashing, and G10 circuit board.  All of these are
lossy.  I think you mean coffee cans.  The problem I have with those
is that a biquad will have the same amount of gain, in a simpler to
build design.  Also, the construction of most coffee cans are truely
sloppy.  I'm often amazed that they work at all.

Quoted text here. Click to load it

I didn't notice that.  There's also some web pile that's building
horizontally polarized slotted waveguide antennas out of galvanized
drain spout pipe.  Whatever (allegedly) works.  Show me some
measurements and field tests, and I'll become a believer.

Quoted text here. Click to load it

You can build the reflector to be the same width as the patch.
However, this will create some leakage in the reverse direction.  It's
not huge, not fatal, and only drops the gain about 1-2dB.  However,
it's an un-necessary "feature" that is only justified for cramped
conditions.  In general, all the reflector type antennas have to have
reflectors larger than the driven element or they too will leak.

A common exception to this rule are the ceramic subtate patch antennas
for GPS and 2.4GHz.  See:
|  http://jeffl.ihwy.com/linksys/wusb11/wusb11-1.jpg
|  http://jeffl.ihwy.com/linksys/wusb11/wusb11-3.jpg
That's an old Linksys WUSB11 radio.  The patch antenna is the round
disk on the right with "CTI" printed on it.  It's less than 1" in
diameter and much smaller than one would expect from a patch antenna.
Yet, it's a real patch design, sitting on a ceramic substrate with
e=10 or more, which makes it very small.  However, the ground plane
under the board is quite large.  It has to be or the patch will
radiate some signal downward, which is quite useless with this device.

Quoted text here. Click to load it

Trust me, it's there.  See:
|  http://www.orbanmicrowave.com/antenna_application_notes.htm
Note that the ground plane is somewhat larger than the patch due to
"fringe field" effects also known as end and edge dispersion.  Also,
the bandwidth of the patch antenna is directly related to its height
above the ground plane.  The higher the patch, the greater the
bandwidth.  However, the higher the patch, the wider the reflector
needs to be to again prevent leakage.

Another article on patch design.
|  http://www.mwrf.com/Articles/Index.cfm?Ad=1&ArticleID=6993

Quoted text here. Click to load it

Nope.  Wood is admitedly hygroscopic (absorbs water).  However, the
patch antenna is a fairly low impedance device.  The conductivity of
the water in the insulators is not sufficiently hight to have any
affect on the patch.  The trick is to NOT the spacers as close to the
50 ohm feed point as possible to reduce conduction effects.  If the
spacers were near the edges, the leakage would certainly have a bigger
effect.

Quoted text here. Click to load it

I'll do some photos.  I've always wanted to post some photos and
designs.  I even registered a new domain for the purpose.  However,
I'm not currently prepared to supply design and construction details.
Too many other projects.  

You're correct that there are few accurate 2.4GHz patch construction
articles around.  I'll see if I can fix that problem.  Patches are
messy to design but easy to build.  I was thinking of designing one
using poly-urathene foam insulation sheets (Techfoam) which has a
convenient aluminum foil backing.

Maxrad WISP24009PTNF.  9dBi gain.  Fairly bullet proof.
|  http://pics.80211junk.com/antennas/Maxrad%209dBi/24009PTNF-01.JPG
|  http://pics.80211junk.com/antennas/Maxrad%209dBi/24009PTNF-02.JPG
Photos are shown in the horizontally polarized position.  This is not
a patch antenna.  I'm guessing (not sure) it's a full wave loop
antenna with a rather bizarre matching section.  I use one as my test
and comparison antenna and have fairly accurate numbers on it.  I'll
post more photos when I get organized.

Quoted text here. Click to load it

Biquad built on the end of a piece of LMR-400.  No connector on the
antenna end.  Copper or aluminium flashing for a reflector.  Maybe
bend the edges up for stiffness.  Solder where needed.  Cheapo plastic
spacers for supporting the loops.  Attached with hot melt glue.

If you wanna do USB, I still suggest you remove the tiny PIFA antenna,
and install either a coax connector, pigtail, or simple dipole
antenna.
--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831.336.2558 voice  http://www.LearnByDestroying.com
#                         jeffl@comix.santa-cruz.ca.us
#                           jeffl@cruzio.com     AE6KS

Re: Wi-Fi antenna brands/quality/reviews


> On Tue, 26 Apr 2005 17:39:19 +0000 (UTC),
> dold@XReXXWi-Fi.usenet.us.com wrote:
>>You don't like the biquad, you don't like the patch.  The soup cans can be
>>found in many places.

> Not exactly.  I really like Trevor's Biquad design.  What I didn't

I meant on the Lincomatic page.  Bad biquad, poor patch, and Heinz Beans
cans... on his page.

> You can build the reflector to be the same width as the patch.

I've read you state the same thing five times now, and I've said the same
thing five times, so I suppose I should get smart and stop.
By my calculations, 50/90 is not "the same width".  But I'll stop.

--
---
Clarence A Dold - Hidden Valley (Lake County) CA USA  38.8,-122.5



Re: Wi-Fi antenna brands/quality/reviews


Quoted text here. Click to load it

thanks for the great info!

Question tho.....since I'm very dumb abt all this....
would you say that its better to have the "radio" part
in the antenna itself such as the designs using a USB
key in the can?

Or is it better to have the radio part in the laptops
itself and just the antenna part external?

Also,... any laptops better than others for war driving
usage?

Re: Wi-Fi antenna brands/quality/reviews


On Sun, 24 Apr 2005 15:15:24 -0700, "Steven Scott"

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Variations in quality of construction and materials will produce wide
variations in pricing.  An indoor patch antenna does not need to have
anti-corrosion protection, corrosion proof materials, water proof
connectors, strong pipe mounts, and bullet proof packaging.  A similar
gain outdoor antenna may be built quite differently.  Cheapo patch
antennas might be built on hi-loss G10 circuit boards, while the more
expensive variety will use pricy TFE-epoxy boards.

So, what your requirements and how will the antenna(s) be used?  Your
question is far too general for a specific answer.

As for distributors, I like:
  http://www.ecomwireless.com
  http://www.fab-corp.com
For patch antenna manufacturers, I've had good luck with Maxrad WISP
series:

http://www.maxrad.com/cgi/maxrad_products_ind.cgi?product=10016&catalog=10001

--
Jeff Liebermann    jeffl@comix.santa-cruz.ca.us
150 Felker St #D   http://www.LearnByDestroying.com
Santa Cruz CA 95060    AE6KS  831-336-2558

Re: Wi-Fi antenna brands/quality/reviews


Thanks for the quick response. :) I'll take a look at the links you've sent
me - I appreciate it.

At the moment, the I'm trying to help cover my friend's house with a single
access point. There are a number of people in the house that will be using
the wireless for Internet browsing (6 roommates with laptops). I don't think
that a patch antenna would be the best choice here, it was just used as an
example.

My though is to use an 8dbi omni, mounted in the attic (inverted) and placed
in the center of the house. Output from the AP is 100mw (but I have 250mw
amp if I need it). The approximate size of the home is 30' x 90', two
stories.

I'm just wondering how much difference a "good" antenna makes over a "cheap"
one. I've not been able to find any reviews, comments or other
non-sales/useful information about different manufacturers or types. Each
company will give you their "pitch", but none of them can seem to back it up
with real data.

s.



> On Sun, 24 Apr 2005 15:15:24 -0700, "Steven Scott"
>
>>So here is my question: Has anyone seen any *real* information or had any
>>experience with antenna manufacturers/distributors? I'm willing to pay
>>more
>>for quality, but I can't seem to determine which products are actually
>>good
>>and which are just "expensive".
>
> Variations in quality of construction and materials will produce wide
> variations in pricing.  An indoor patch antenna does not need to have
> anti-corrosion protection, corrosion proof materials, water proof
> connectors, strong pipe mounts, and bullet proof packaging.  A similar
> gain outdoor antenna may be built quite differently.  Cheapo patch
> antennas might be built on hi-loss G10 circuit boards, while the more
> expensive variety will use pricy TFE-epoxy boards.
>
> So, what your requirements and how will the antenna(s) be used?  Your
> question is far too general for a specific answer.
>
> As for distributors, I like:
>  http://www.ecomwireless.com
>  http://www.fab-corp.com
> For patch antenna manufacturers, I've had good luck with Maxrad WISP
> series:
>
> http://www.maxrad.com/cgi/maxrad_products_ind.cgi?product=10016&catalog=10001
>
> --
> Jeff Liebermann    jeffl@comix.santa-cruz.ca.us
> 150 Felker St #D   http://www.LearnByDestroying.com
> Santa Cruz CA 95060    AE6KS  831-336-2558




Re: Wi-Fi antenna brands/quality/reviews


> At the moment, the I'm trying to help cover my friend's house with a
> single access point. There are a number of people in the house that will
> be using the wireless for Internet browsing (6 roommates with laptops).

Six people using wireless simultaneously?  Or surfing simultaneously?  With
shared DSL, everyone can tell when a bittorrent is downloading.  There is
only so much speed on the internet link, which you are sharing.  You are
also sharing the wireless speed, if there's any gaming going on.

> My though is to use an 8dbi omni, mounted in the attic (inverted) and
> placed in the center of the house. Output from the AP is 100mw (but I
> have 250mw amp if I need it). The approximate size of the home is 30' x
> 90', two stories.

I cover a 65x105 house nicely with a Netgear at the one end with EZ-12
Windsurfer reflector on the one stock vertical antenna.  In a townhouse,
the router is upstairs, and two PCs are downstairs.  Here the router is
near the floor, on the second floor, at the back of the house.  It has two
antennas, parallel to the floor, each with an EZ-10 corner reflector.  The
performance is not so good on one of the PCs because it has an internal PCI
card with the antenna on the "wrong" side of the PC, shielded from the
router.

> I'm just wondering how much difference a "good" antenna makes over a
> "cheap" one. I've not been able to find any reviews, comments or other

Except for the Signal Seeker, most antennas are what they are, presuming
there's no outright fraud.  Indoor mounting puts you at the low end of the
demand range.  Outdoor applications are subject to widely varying long term
durability due to differing materials.

Jeff is more concerned with industrial quality.  I like reflectors although
I do have one commercial antenna.  

http://www.freeantennas.com EZ-12 is easy to make.  Print it on some heavy
stock.  I used photo paper.  If you have twin antennas, you can make two,
in the size that it comes.  If you have one antenna, you can enlarge it to
full sheet.  

--
---
Clarence A Dold - Hidden Valley (Lake County) CA USA  38.8,-122.5



Re: Wi-Fi antenna brands/quality/reviews


On Sun, 24 Apr 2005 17:53:10 -0700, "Steven Scott"

>At the moment, the I'm trying to help cover my friend's house with a single
>access point. There are a number of people in the house that will be using
>the wireless for Internet browsing (6 roommates with laptops). I don't think
>that a patch antenna would be the best choice here, it was just used as an
>example.

Actually, I think a patch antenna would be an excellent choice.
They're cheap, about the right gain, and have a wide -3dB beamwidth.
The beamwidth is critical in "illuminating" the house.  An antenna
with the same gain, but a narrower beamwidth can only light up parts
of the house.

>My though is to use an 8dbi omni, mounted in the attic (inverted) and placed
>in the center of the house.


In general, going through three or more walls is going to be a
problem.  If there is metal in the walls (foil backed insulation),
it's impossible.  For multiple floors, I always recommend one access
point per floor, using different channels (1,6,11), but the same SSID.
Well, actually I use different SSID's on different floors so its
possible to select which access point I'm using.

Also, high gain omni antennas are not a great idea for multiple
floors.  The vertical radiation angle of your proposed 8dBi ommi is
about 20 degrees which means that clients above and below the
horizontal plane will have problems connecting.  Certainly users
directly above and below the access point will have problems.  Omnis
are also more susceptible to internal reflections and multipath.

>Output from the AP is 100mw (but I have 250mw
>amp if I need it). The approximate size of the home is 30' x 90', two
>stories.

General construction materials?  Any metal in the walls or floors?
Approximate location of access point?  How many walls must the signal
pentrate to the worst location?

>I'm just wondering how much difference a "good" antenna makes over a "cheap"
>one.

There are only three characteristics worth noteing.
  1.  Antenna Gain.
  2.  Antenna pattern (beamwidth).
  3.  VSWR over the bandwidth.
As far as these characteristics are concerned, there's no difference
between a "good" or "bad" antenna.  However, variations in
construction methods and materials will have some effects.  Whatever
you do, don't assume that higher gain equals higher quality.  

>I've not been able to find any reviews, comments or other
>non-sales/useful information about different manufacturers or types. Each
>company will give you their "pitch", but none of them can seem to back it up
>with real data.

Well, antennas are fairly close to magic.  It's not possible to "see"
RF.  The published antenna patterns are often science fiction, where
the mounting location has a huge effect.  Verifying test patterns with
field tests often discloses huge discrepancies with the computer
models and large experimental error.  Even the computer models vary
substantially due to variations in assumptions and algorithms.  Most
"reviews" mention the gain and that's about it.  A few are misleading
such as those that advertise the antenna gain, but completely ignore
the losses in the attached coax cable.  If you're interested, I can
point you to web sites that do a comparative analysis of different
antenna types but will require some expertise to understand.  Start
here:
  http://www.qsl.net/n1bwt/contents.htm



--
Jeff Liebermann    jeffl@comix.santa-cruz.ca.us
150 Felker St #D   http://www.LearnByDestroying.com
Santa Cruz CA 95060    AE6KS  831-336-2558


Re: Wi-Fi antenna brands/quality/reviews


> Well, antennas are fairly close to magic.  

So Ed might be right?

--
---
Clarence A Dold - Hidden Valley (Lake County) CA USA  38.8,-122.5



Re: Wi-Fi antenna brands/quality/reviews


On Mon, 25 Apr 2005 14:45:57 +0000 (UTC),
dold@XReXXWi-Fi.usenet.us.com wrote:

>> Well, antennas are fairly close to magic.  

>So Ed might be right?

Yes.  Ed is a magician.  Ever watch a magician in action?  The
majority of the audience has no clue how it's done, instinctively know
that it's all a fake, and can rarely be convinced of anything beyond
its entertainment value.  However, there is always a minority of
believers, that can be convinced of anything, and often can be made to
pay for it.  Those are called customers and Ed knows how to make them
pay.

I somewhat envy Ed.  I have no sales abilities.  If I don't bury the
customers in technobabble, I bore them to death with detail.  Clear
cut pronouncements of superiority ("this is the best") are replaced
with my attempts to quantify that intangibles.  I'll often criticize
ALL the products on the assumption that the customer wants to be
informed or educated.  I often have trouble giving things away.

My introduction into electronics and antennas in the late 1950's was
inspired partly by reading an article about someone getting charged
with fraud for selling "turn your house wiring into a giant 1000ft TV
antenna".  What I couldn't understand was that it was an obvious
fraud, dangerous as implemented, yet the advertisements in Popular
Electronics continued every month, and people continued to buy it.  At
first, I just wanted to understand how it works.  Later, I decided my
goal in life was perform a similar fraud.  Antennas seemed perfect.
You can't see the RF, you can touch the electrons, few people
understand how they work, and you can't live without them.

So, I study Ed system and try to understand his methods.  He relies on
testimonials and a growing reputation.  The comments from buyers on
eBay are 97.5% favorable.  They like Ed and his products.  He must be
doing something right?  My basic problem is that I need an income when
I retire and antennas look like a good possibility.

I see all this as an indication that the world is ready for my line of
designer boutique antennas and radios.  Instead of boring technical
specifications and reproducible tests, I plan to sell my antennas as
magic, amazing, miracle, turbo, accelerated, enhanced, self-boosted,
secret, and other superlatives.  Instead of plain white fiberglass, my
antennas will be sculpted and embellished with "signal enhancing
semi-precious crystals and jewels".  Instead of simple geometric
shapes, they will look like something out of a science fiction movie,
on the assumption that the weirder it looks, the better it works.

If I succeed, I can thank Ed for the inspiration, the proof that it
can be done, and the magic necessary to make it happen.


--
Jeff Liebermann    jeffl@comix.santa-cruz.ca.us
150 Felker St #D   http://www.LearnByDestroying.com
Santa Cruz CA 95060    AE6KS  831-336-2558


Re: Wi-Fi antenna brands/quality/reviews


>I see all this as an indication that the world is ready for my line of
>designer boutique antennas and radios.  Instead of boring technical
>specifications and reproducible tests, I plan to sell my antennas as
>magic, amazing, miracle, turbo, accelerated, enhanced, self-boosted,
>secret, and other superlatives.  Instead of plain white fiberglass, my
>antennas will be sculpted and embellished with "signal enhancing
>semi-precious crystals and jewels".  Instead of simple geometric
>shapes, they will look like something out of a science fiction movie,
>on the assumption that the weirder it looks, the better it works.

And, since they'll be sold by the universally recognized guru of
a.i.w, they'll be a sure hit!  Sign me up!  8*)



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