Cut and past your way to better WiFi reception? It costs pennies and takes the fabrication skills of a kindergartner... then bend a 6dBi Omni and a 10dBi directional out of copper wire!
David's got a bit of trouble getting his WiFi Router signal to reach every corner of his house... one of the easiest fixes ever isn't a trip to the local computer store, but a trip to the kitchen for aluminum foil, then to the home office for a manilla folder and a glue stick.
It's the infamous Ez-12 Parabolic Reflector, hosted at FreeAntennas.com.
Here's the EZ-12 template link.
Omnidirectional Antennas = radiate signal 360 degrees...
A panel mount or surface mount female N connector and 300mm of solid core copper is the heart of the Home-brew Compact 6dBi Collinear Antenna a slick e found on MartyBugs.net.
Directional Antennas = generally concentrates your WiFi in a single direction.
We went to the Seattle Wireless most excellent collection Antenna HowTo for the SardineCanAntenna a biquad you can build with or without an N-connector, at least at the antenna end! (just search WiFi Biquad to find a host of construction ideas!) You don't have to use a sardine can, just about anything will work as a reflector, even a pressed CD... it just needs to be metallic and around 150mm in diameter.
There are quite a few more WiFi antenna designs out there... these are just some of our faves!
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Posted by mapleshade on 05/08/2008 at 02:35:36 pm in Systm
"
I was hoping you used a can, but gave me some ideas for other beer boxes to use. I happened to have some 80lb card stock, so I printed the design right onto it. I have a WRT54G about 30 feet from a laptop with a Linksys B card. I added the default size windsurfer to one antenna at a time, playing with its positioning and only got moderate if any increased signal. Would I benefit from 2 (1 on each antenna)? If I'm not mistaken, the waves radiate out of the top of the antenna; what's the best vertical positioning of the reflector on the antenna?
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Posted by tarpi on 04/27/2008 at 01:21:20 pm in Systm
Hi, I just wanted to say what a great episode!
I am thinking of doing some tinkering with antennas as well but there is something I was wondering.
Has anyone managed to find a realively inexpensive way of measuring some of the microwave parameters on connectors and antennas.
Following these directions is easy, but at these frequencies, its hard to trouble shoot a bad crimp, or a bad solder, or antenna section that is a little bit off in length. All these things can basically ruin the signal strength leaving you in the dark as to what the problem is? Then you have to start from scratch and hope that it works.
So far I've found the low cost 2.4Ghz spectrum analyzer from metageek at
*link*
and for those willing to tinker even more and save some money, Jason Hecker has made even cheaper spectrum analyzer but with 8-bit resolution which is a bummer because the setup is relly slick. *link*
I think before investing money for connectors, crimp tools, and wire strippers, one should have some ways of troubleshooting problems.
Petar
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Posted by zoozabar on 04/21/2008 at 03:16:29 pm in Systm
first time poster thought I would show off my try at the windsurfer...
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Posted by dmann on 04/19/2008 at 12:39:59 pm in Systm
So, let's pretend that i REEEEEAAAAALLLY dont wanna hack apart my groovy black macbook, but know i will be staying at a nice hotel in July, and as such, it charges way too much for wi-fi.
So, is there a way to use an external USB wifi device to get a signal, that i could then put a nice external antenna on, and grab wi fi from a coffee shop, or cheap motel nearby with an open hot spot?
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Posted by MD2389 on 04/12/2008 at 10:47:10 am in Systm
"
Also, the more adapters you use, the more work you will have to do to match impedance. The KISS philosophy definitely applies here.
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Posted by kickarse on 04/11/2008 at 05:40:22 pm in Systm
Also, if you can help it, the length of the cable and the amount of connectors will help with loss.
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Posted by MD2389 on 04/11/2008 at 10:48:22 am in Systm
"Honnestly? it doesn't matter. i thought about this for a second when I first saw it, but both sides of the foil are reflective and card is transparent to radio waves...
Oh, and as I understand it, the magic length for antennas is not actually 1/4 wave, but it is 1/2 wave. Was Patrick wrong? no. The 1/4 wave antennas are half of a 1/2 wave antenna, and the ground plane reflects this (the car roof in the case of a CB whip, which is also why putting them on the front bumper is a bad idea...) and this produces the waves.
As to how it produces the waves, as I understand it antennas work on the principle of resonance. The antenna must be resonant on the correct frequency (hence all the 1/2 wavelength stuff) and the antenna is fed with what is effectively a very high frequency alternating current (this is while transmitting, where length is most critical) and thus you have moving electrons in a wire leading to electromagnetic fields which masquerade as radio waves. When receiving it is pretty much the same thing in reverse.
The one thing Patrick did not explain very well was about the signal bouncing until it gets a full wave. As I understand it, this is exactly what you don't want. The reason for this actually lies in the coaxial cable used to feed the antenna. It has a certain impedance that should match the impedance of the connectors, antenna and of the transmitter/receiver. When the antenna is not resonant, standing waves are set up whereby some of the power does not get radiated out as radio waves and thus ends up being reflected back down the coax, where it then bounces between ends until it is a full wave and gets emitted. The problem with this is that because of the resistance of the coax, the power is wasted. (which is why in an amateur radio setup, the antenna matching unit ideally should be near the antenna because otherwise the coax still wastes power) so in summary, in an ideal world, the antenna perfectly converts the power to radio waves. This is a standing wave ratio or SWR of 1. (1 watt out for every watt coming back) if you have a severe missmatch, you might end up with an SWR of 3 or more (1 watt out for every 3 watts coming back)
Anyway, hope that answers some questions. If you notice any mistakes in my explanation please feel free to correct. I don't claim to be an expert on this..."
And you just happen to be exactly right. Furthermore, if you have a severe enough mis-match, you WILL burn up your hardware.
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Posted by Dark_Shroud on 04/10/2008 at 09:35:56 pm in Systm
Well at least I have a use for the dish I need to take of my roof.
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Posted by kickarse on 04/10/2008 at 06:34:08 pm in Systm
There's also this one too
*link*
and another
flakey(dot info)/antenna/omni/quarter/
(the posting system doesn't like dot info domains, so just change it out for the realy url)
Another good site here...
*link*
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Posted by zeronome on 04/10/2008 at 02:26:48 pm in Systm
Back to WiFi.... I was very surprised to not hear about a pringles can on the show... EPIC wireless antenna
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