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Antena For Alfa Wif


Malachai
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Hello,

hope everything is good. I'm hopping someone could help me out. I bought ALFA USB WiFi AWUS036H a couple weeks ago. I keep hearing Darren talk about a longer and bigger antena to attach to the device. Where can I find the antenal for this? I looked at radio shack, and best buy. Nothing .

Any info would be good.

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Biggest thing with antennas is to match up the mhz/ghz to what you're doing with them. 2.4ghz is b/g wifi and is probably what you're looking for.

With any RF signal, the most important aspects in regards to range is transmit power and receive sensitivity. I'm assuming you're trying to sniff some packets on an open wifi hotspot, so Tx (transmit) power is out of your control. The Rx (receive) sensitivity is measured in dBm - every 6 dBm doubles your range in an open enviroment, every 12 dBm doubles your range in indoor/urban enviroments. Theres two main types of antennas - omni directional and Yagi. Omni's are great for war driving, as they work 360 degrees around the antenna - so driving down a street, you'll pickup wifi hotspots on both sides of the road. Think of Yagi antennas as a focused beam, not unlike a laser. They shoot out in whatever direction you point them in very well, and do very poorly for omni directional stuff. The other big thing to consider is crap in the way. What I mean by this is, the higher the frequency (2.4ghz is the frequency of most wifi and is quite high - 5ghz wifi is worse) the more the signal is going to be degraded by studs, sheetrock, concrete, metal, doors, any physical barrier really. So removing as many obstacles in your way as possible will greatly help your cause. Hope this helps!

telot

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Biggest thing with antennas is to match up the mhz/ghz to what you're doing with them. 2.4ghz is b/g wifi and is probably what you're looking for.

With any RF signal, the most important aspects in regards to range is transmit power and receive sensitivity. I'm assuming you're trying to sniff some packets on an open wifi hotspot, so Tx (transmit) power is out of your control. The Rx (receive) sensitivity is measured in dBm - every 6 dBm doubles your range in an open enviroment, every 12 dBm doubles your range in indoor/urban enviroments. Theres two main types of antennas - omni directional and Yagi. Omni's are great for war driving, as they work 360 degrees around the antenna - so driving down a street, you'll pickup wifi hotspots on both sides of the road. Think of Yagi antennas as a focused beam, not unlike a laser. They shoot out in whatever direction you point them in very well, and do very poorly for omni directional stuff. The other big thing to consider is crap in the way. What I mean by this is, the higher the frequency (2.4ghz is the frequency of most wifi and is quite high - 5ghz wifi is worse) the more the signal is going to be degraded by studs, sheetrock, concrete, metal, doors, any physical barrier really. So removing as many obstacles in your way as possible will greatly help your cause. Hope this helps!

telot

Thank you very much for helping me understand all this stuff. Thanks @Vodmya for the link. I was able to find one I think is good but I would need your advice to make sure I'm getting a good one. From reading your post I think I am based on how much ghz is has. If you could look at it and see if its good. I plan on war driving later on down the road but for now I'm working at home understand all this and seeing how my neighberhood has there network hahahah

Here's what I think might be good.

http://www.data-alliance.net/-strse-531/Antenna-12dbi-Alfa-RP-dsh-SMA/Detail.bok

or what about this one.

http://www.amazon.com/10-dBi-2-4GHz-WIFI-Antenna/dp/B000SEQGT2/ref=pd_rhf_se_p_t_2

Edited by Malachai
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Thank you very much for helping me understand all this stuff. Thanks @Vodmya for the link. I was able to find one I think is good but I would need your advice to make sure I'm getting a good one. From reading your post I think I am based on how much ghz is has. If you could look at it and see if its good. I plan on war driving later on down the road but for now I'm working at home understand all this and seeing how my neighberhood has there network hahahah

Here's what I think might be good.

http://www.data-alliance.net/-strse-531/Antenna-12dbi-Alfa-RP-dsh-SMA/Detail.bok

or what about this one.

http://www.amazon.com/10-dBi-2-4GHz-WIFI-Antenna/dp/B000SEQGT2/ref=pd_rhf_se_p_t_2

Both are excellent choices when on a budget (I am as well). When you're ready to upgrade to the big leagues, and don't mind your car getting some funny looks, I know a guy who has one of these mounted outside his car for even better reception. http://www.google.com/products/catalog?q=12+dbi+gain+omni&hl=en&rlz=1C1CHFX_enUS436US436&prmd=imvns&um=1&ie=UTF-8&tbm=shop&cid=14723059388463375015&sa=X&ei=DjTzTuGqGcPg0QGM49CsAg&ved=0CGwQ8wIwAA

good luck on your drive!

telot

Edited by telot
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Both are excellent choices when on a budget (I am as well). When you're ready to upgrade to the big leagues, and don't mind your car getting some funny looks, I know a guy who has one of these mounted outside his car for even better reception. http://www.google.com/products/catalog?q=12+dbi+gain+omni&hl=en&rlz=1C1CHFX_enUS436US436&prmd=imvns&um=1&ie=UTF-8&tbm=shop&cid=14723059388463375015&sa=X&ei=DjTzTuGqGcPg0QGM49CsAg&ved=0CGwQ8wIwAA

good luck on your drive!

telot

Well thanks again for making me understand and learning something new. I notice that they have different dBi on them. Would you recomend the higher the better? Plus is there any cons on going higher?

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Well thanks again for making me understand and learning something new. I notice that they have different dBi on them. Would you recomend the higher the better? Plus is there any cons on going higher?

No cons whatsoever! Higher the better. 12dBi should be plenty. If you go with one of the external mounts, just keep in mind the signal degrades over the length of the line, so use high quality wire and keep it as short as possible.

telot

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No cons whatsoever! Higher the better. 12dBi should be plenty. If you go with one of the external mounts, just keep in mind the signal degrades over the length of the line, so use high quality wire and keep it as short as possible.

telot

Well I was going to use a short usb cable that came with it. Do you think that would be good enough? I was planning to use it in the house and down the road in the car.

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The USB cable can be as long as you want. I was referring to the external mounted antenna (the link I posted above) wire that leads in to your alfa. Its the alfa that is receiving the wifi signal, not your computer, so the cable can be as long as usb cables can be (anyone know how long that is?)

telot

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Excellent! Thanks misfitman

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