Wi-Fi antenna brands/quality/reviews

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

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Hyperlink HG2409P Patch antenna: $24.95
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Some of the other places I've looked include: WinnCom

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Connectronics
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Wi-Fi Plus (www.wifi-plus), Symbol, Cisco, Hawking
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Andrew
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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

Reply to
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:

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patch antenna manufacturers, I've had good luck with Maxrad WISP series:

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Reply to
Jeff Liebermann

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.

Reply to
Steven Scott

Reply to
tzar

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.

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.

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.

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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.

Reply to
dold

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.

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.

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?

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.

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:

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Reply to
Jeff Liebermann

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.

Reply to
Jeff Liebermann

I'm new to all this

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

If yes... what do you recommend?

Reply to
me

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

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.

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.

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.

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.

Reply to
Jeff Liebermann

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?

Reply to
me

So Ed might be right?

Reply to
dold

I have the following for sale to enable house to house wireless internet. Used for 1 week

2 - antennas
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?cPath=21_23&­products_...1 10 foot cable assembly -
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?products_id=­1861 25 foot cable assembly -
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?cPath=41_56&­products_...

snipped-for-privacy@hotmail.com

$95 delivered via ground carrier

Reply to
WayneS

There are certainly some commercial mag-mount antennas intended for automotive use.

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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.

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patch panel is probably the cleanest design.
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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.

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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:
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There are combination USB radio with antenna from Hawking and others.
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Reply to
dold

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*)

Reply to
William P. N. Smith

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.

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mentions the fault with Trevor's site, and has better instructions and pictures.

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

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

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

Reply to
dold

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.

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.

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

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I'm still learning the program and am having problems.

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.

Reply to
Jeff Liebermann

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.

They just stole the commercial design of

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shows the reflector as 90mm diameter, and the patch at 46x50. They should have stolen a better design?

Reply to
dold

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.

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

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.

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. |

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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: |

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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.

Reply to
Jeff Liebermann

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

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.

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.

Reply to
dold

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.

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.

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: |

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'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.

Trust me, it's there. See: |

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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. |

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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.

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. |

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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.

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.

Reply to
Jeff Liebermann

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