"Cantennas" to increase wifi transmitter range

What are some do-it-yourself ways that you can increase the range of a wifi transmitter? I've heard stuff like you can make a "cantenna" by putting a pringles can over the antenna, and that's supposed, but it didn't work for me. I've also heard that this is illegal because of the FCC. Is that true, and if so, why? I have a syslink wifi transmitter/router/switch. It's supposed to work at 150 feet, but it's definitely not doing that for me. It's in a wooden house. I have it sitting in a room where there is a big cathode ray tube TV strait through the room for it, could that me interferring with it? Even though when it's turned off?

Reply to
DJ Craig
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[alt.comp.networking.connectivity deleted because Newsguy claims it's bogus]

Better antenna or better location. Antennas can vary from simple reflectors:

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various forms of corner reflector, biquad, dish, panel, patch, yagi, omni, ad nausium antennas. Note that the antenna does not generate any RF. It merely redirects it. If you want to increase the antenna gain in one direction, there is a corresponding loss of gain in other directions. Tailoring the antenna pattern to your unspecified requirements is paramount in the selection of an appropriate antenna.

Please tell me you didn't hear someone recommend putting a pringles can over an omni directional antenna found one a typical access point. That won't work.

If you're in Tennessee, why did you post this question to a UK newsgroup?

It's not totally illegal to modify a wireless system by replacing the antenna. Note that the rules changed on Nov 22. Section 15.204(c)(4) proclaims: Any antenna that is of the same type and of equal or less directional gain as an antenna that is authorized with the intentional radiator may be marketed with, and used with, that intentional radiator. No retesting of this system configuration is required. What this means is that you can't change the type of antenna that is supplied or use a version that has a higher gain, unless the manufactory has bothered to type certify their system with the higher gain antenna. In other words, most of the aftermarket antennas are in violation of 15.204(c)(4).

Why is it true or why is it so? I guess I have to answer both questions. It's true because the FCC is deathly afraid that congress might realize that the FCC's protectionist mentality toward large monopolies, and the obvious and phenomenal success of unlicensed services, might suggest to an elected official of moderate intelligence that the FCC is largely obsolete and not serving any useful purpose.

As to why it is so, the rule was established to all manufacturers to offer for sale aftermarket antennas without requiring recertification. Prior to about 2002, replacement of antennas was totally prohibited.

That's nice. Any particular model number?

Fine. How far are you going? How fast? How many walls are you going through? Wood is not transparent to RF. Got any foil backed insulation in the walls? How about antique foil backed wallpaper?

Does it work when your unspecified client radio (it takes two to tango) is in the same room as the Syslink something? In other words, if you remove the walls and range issues, does the system work? It's possible that either end is busted, misconfigured, or getting trashed by intereference.

No. The TV set is probably not causing problems. The usual sources of intereference are other 802.11b/g systems, municipal wireless networks, microwave ovens, 2.4Ghz cordless phones, wireless security cameras, and anything else that belches 2.4GHz.

Reply to
Jeff Liebermann

No, our fish are in an outside pond and I don't think they eat radio signals ;-)

But the TV is a 32 inch Sony CRT in the next room, right behind the router. Of course it has a lot of big coils and a very thick glass screen that might behave the same way as an aquarium. In fact it would make quite a good aquarium.

Do you know if is possible to put an extension arial on the router. This model has two antenae.

Reply to
DJ Craig

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The above site actually advertises an extension antenae for this purpose. I might need two. But I would still be interested in the story about a cantenna or any other Do-it-yourself method.

Reply to
DJ Craig

Do you have a big aquarium in the way? Seriously, that can interfere with the signal.

Reply to
Joseph Stewart

Thus spake DJ Craig:

It's not the aquarium's glass that causes problem for wireless signals; it's the water. Water is death to wireless signals. That's why trees are such a hinderance to wireless; leaves "look" like little bags of water to the wireless devices.

If the TV is such a big concern for you, experiment by putting your router on top of the TV. Does that make your reception better?

Many antennae available to connect to your router.

Reply to

Take a look at my web site for information on the cantenna I used with great success.

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If you do a search for "cantenna" in newsgroup alt.internet.wireless you should find LOTS of info (I found 341 entries).


Reply to
Bob Alston

Joseph Stewart wrote in vUjif.16716$ snipped-for-privacy@fe12.lga:

Likewise, if you put the access point in the loft to get the aerial as high as possible to increase the range, beware of the header tank for the hot water: it will absorb almost all the signal sent in that direction - as I found when I put my parents' wireless adaptor in the loft: there was a huge "shadow" on the side of the house shielded by the tank. The other problem was overheating of the wireless adaptor in the summer heat up in the loft, which isn't so much of an issue at this time of year now it's -2 deg C outside!

Many people don't realise that a large tank of water (even if the tank is made of plastic) will absorb wireless network signals because 2.4 GHz is the resonant frequency of water - which is why food (which contains water) heats up in a microwave oven and why this frequency is available for short-range wireless networking because it is useless for long-range transmission since water in the atmosphere will attenuate the signal.

Reply to
Martin Underwood

That's because you have to actually make an antenna out of the pringles tin, not just stick it over the existing antenna, f****it.

You're posting to a UK group and the FCC have nothing to do with us.

Reply to

What designates this as a UK group? Should it not be alt.internet.wireless.uk? This is the first I've heard of this being a UK group. It seems that there is more US activity on the group than UK Just wondering... Bill C.

Reply to

It's a bit more complicated than that - there are plenty of websites that tell you how to do it properly.

Here in the UK we don't worry too much about the FCC :-)

Reply to
Rob Morley

Cross posted to alt.comp.networking.connectivity,alt.internet.wireless,comp.sys.mac.com m,uk.comp.home-networking

As such, its not exclusive to the UK.


Reply to
D. Kirkpatrick

It was crossposted to a UK group, so Jeff Liebermann was clearly responding to the post from that group, but replied by crossposting to the groups to which the OP posted.

Reply to
Tristán White

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