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Author Topic: Yagi Antenna modified to become Yagi CANTENNA?  (Read 131 times)

Vesp

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Yagi Antenna modified to become Yagi CANTENNA?
« on: September 27, 2011, 11:19:11 AM »
So I have a 2,000mw  alfa WiFi Adapter and a 25dbi (2.4G?) Yagi antenna. I bought the whole set up for maybe about $75 including shipping.

So I am curious if it would be a simple task to turn my Yagi that looks like this:
 

Put it in a metal pipe of the right size, shape, and placed in the correct location and turn it into a into a Yagi CANTENNA? which generally look like this:

 

Will a mega sized pringles can do the trick, or will that Yagi design not work well if it is put into a can of some sort?
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lugh

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Re: Yagi Antenna modified to become Yagi CANTENNA?
« Reply #1 on: September 27, 2011, 12:45:46 PM »
Yagi antennas are generally enclosed in a tube to protect the components from the weather  ;)  A cantenna works like a yagi antenna, so no benefit is obtained by combining them  :P  Some links to relevant e-books:

h**p://www.ab9il.net/wlan-projects/EnlaceAguila_Baul_EN.pdf

ww w.wndw.net/pdf/wndw2-en/wndw2-ebook.pdf

that may increase understanding  ???
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Vesp

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Re: Yagi Antenna modified to become Yagi CANTENNA?
« Reply #2 on: September 27, 2011, 12:54:38 PM »
Ok that is what I originally thought but I saw someone was selling "yagi cantennas" and got concerned that I could improve distance by just putting a can around it, in addition too seeing a diagram about placing the antenna a certain distance from the back -- thought it might have been a way to improve it.


Anyways, I will look at those PDFs better tomorrow... I need sleep, as I can hardly type.

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lugh

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Re: Yagi Antenna modified to become Yagi CANTENNA?
« Reply #3 on: September 27, 2011, 02:27:26 PM »
Quote
75 bucks for something that could be made from a coffee can.

As in most technical device purchasing, there are a lot of vendors who make a good living selling such equipment to the public    :P   Most of us would have a hard time constructing a USB wi fi card   ::)   Buying the other hardware involved in constructing a cantenna can be costly unless one gets enough for several units to reduce the overall shipping costs    ;)  Some useful links were provided in:

http://127.0.0.1/talk/index.php/topic,2033.msg23969.html#msg23969

and some other links are:

h**p://urbanwireless.info/antennas/dish-with-biquad-feed

h**p://www.ab9il.net/wlan-projects/wifi1.html

h**p://www.wifiview.com/About_Us.html

h**p://www.wirelessnetworkproducts.com/increasingwirelessrange.aspx

h**p://www.instructables.com/id/My-WiFi-Signal-Booster-Wok-Antenna-w-Directional-/

h**p://www.instructables.com/id/%22Poorman_s-WiFi%22--USB-adapters-%26-DIY-cookware-refl/

h**p://www.instructables.com/id/Wifi/

h**p://www.instructables.com/id/usb-wifi-antenna/

h**p://www.instructables.com/id/Uni-Directional-WIFI-Range-Extender/

h**p://www.instructables.com/id/Cheap_WiFi_Range_Extender/

h**p://www.instructables.com/id/Dell-Laptop-WI-FI-High-Gain-Antenna-Mod-Increase-_1/

h**p://www.instructables.com/id/How-To-Make-A-Wifi-Antenna/

h**p://www.instructables.com/id/10--WIFI-16dBi-Super-Antenna-Pictorial/

h**p://www.instructables.com/answers/how_to_combine_wifi_yagi_antena_with_usb_wifi_adap/

and the previously posted lowest cost approach:

h**p://www.instructables.com/id/The-Wireless-Internet-Cantenna-gets-Dished/

the attached article explains interference measurements  8)




« Last Edit: September 27, 2011, 03:06:04 PM by lugh »
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Terror

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Re: Yagi Antenna modified to become Yagi CANTENNA?
« Reply #4 on: September 27, 2011, 04:34:52 PM »
Aircrackn are we? I have a yagi and an omni both of which are tplink brand and plug into my tplink atheros 9k USB stick - I have bcktrack running on USB in persistant mode which makes for good fun on the run :-)
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Vesp

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Re: Yagi Antenna modified to become Yagi CANTENNA?
« Reply #5 on: September 27, 2011, 08:04:34 PM »
Quote from: reckless on September 27, 2011, 01:08:52 PM
Quote from: Vesp on September 27, 2011, 11:19:11 AM
about $75 including shipping.
75 bucks for something that could be made from a coffee can.
A good portion of that was the 2 watt WiFi adapter. The actual Yagi antenna only cost around $12 including shipping (Also I bought ~15 ft of USB included in that price) -- Also it came with a 9.6 (?) dbi omni-directional antenna and a 6 dbi omni-directional antenna. Also I am not sure if it was 75, kind of in the ball park with that figure. I can only really be sure of it costing me maybe $60 with everything.


It is good for aircracking, I.e the right drivers, etc etc --- but I am not doing that - I just wanted to get faster Internet for free.
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lugh

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Re: Yagi Antenna modified to become Yagi CANTENNA?
« Reply #6 on: September 27, 2011, 09:34:07 PM »
A rather important fact about those USB wi fi cards that's not widely known is that they are designed in a manner that will cause them to fail from overheating unless they're suspended in the air to maximize cooling  8)
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Sydenhams chorea

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Re: Yagi Antenna modified to become Yagi CANTENNA?
« Reply #7 on: October 20, 2011, 05:39:12 AM »
I use a 9dBi omnidirectional antenna but the signals are still a tad too weak. I was thinking of constructing a biquad, does anyone here have experience with that?
It is perhaps the narcotic. Hyoscine affects certain people very oddly. One cannot be sure. Sometimes, these cases take strange forms. The victim becomes in a sense, 'mediumistic', a vehicle for all the intangible forces in operation around her.

Vesp

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Re: Yagi Antenna modified to become Yagi CANTENNA?
« Reply #8 on: October 20, 2011, 09:21:35 AM »
What is the advantage and disadvantage of those compared to a yagi or a can?

How many mW is your wifi adapter to go along with your 9bBi?
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Re: Yagi Antenna modified to become Yagi CANTENNA?
« Reply #9 on: October 20, 2011, 03:26:12 PM »
It's a WifiSKY 56G with RTL8187 chipset. Said to have an operating distance of up to 500 meters in free space.

Good torrents come in at only 20-30 kb/s, sometimes even less.
It is perhaps the narcotic. Hyoscine affects certain people very oddly. One cannot be sure. Sometimes, these cases take strange forms. The victim becomes in a sense, 'mediumistic', a vehicle for all the intangible forces in operation around her.

Vesp

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Re: Yagi Antenna modified to become Yagi CANTENNA?
« Reply #10 on: October 20, 2011, 10:19:30 PM »
I see. So it is 1,000mw?

Did you ever try putting it outside on a longer USB cord? That seems to help if you are taking it from people...


A biquad looks hard to make IMO, does that 8 shape have to be the proper size and everything for the right frequency? I do not understand the concept of it.
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dream0n

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Re: Yagi Antenna modified to become Yagi CANTENNA?
« Reply #11 on: October 20, 2011, 10:40:15 PM »
What does your "speedtest.net" result come in as? That is usually a better test than what speed your torrents are coming in at.
 Because of a few reasons, mainly, upload speed and NAT issues.
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lugh

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Re: Yagi Antenna modified to become Yagi CANTENNA?
« Reply #12 on: October 21, 2011, 12:12:56 AM »
Quote
A biquad looks hard to make IMO, does that 8 shape have to be the proper size and everything for the right frequency? I do not understand the concept of it.

Perhaps pictures of a single bi-quad feeder:

h**p://trevormarshall.com/biquad.htm

h**p://www.engadget.com/2005/11/15/how-to-build-a-wifi-biquad-dish-antenna/

h**p://koti.mbnet.fi/zakifani/biquad/

and a double bi-quad:

h**p://www.instructables.com/id/Bi-Quad-WiFi-Antenna/

and this ehow with some links:

h**p://www.ehow.com/how_7465034_build-biquad-wifi-antenna.html

will make it clear how it amplifies the signal  8)
« Last Edit: October 21, 2011, 01:07:32 AM by lugh »
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micro

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Re: Yagi Antenna modified to become Yagi CANTENNA?
« Reply #13 on: November 08, 2011, 05:45:45 PM »
You wont be getting 25dBi from aa yagi with that little elements. Or even a single yagi.
You need a phased array for proper wardriving.
And do note that the PVC radome has an effect on the resonance of the antenna.
Yagis with radomes have been designed that way.

http://www.bigskyspaces.com/w7gj/AntennaFarm04.jpg
« Last Edit: November 08, 2011, 05:49:21 PM by micro »

lugh

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Re: Yagi Antenna modified to become Yagi CANTENNA?
« Reply #14 on: November 08, 2011, 09:26:29 PM »
It would take a rather large truck and trailer to haul that phased array around for wardriving  ;) Those that want to understand how phased array antennas work should read:

h**p://ifile.it/hod4wp/ebooksclub.org__Array_and_Phased_Array_Antenna_Basics.pdf

 8)
« Last Edit: November 08, 2011, 09:44:26 PM by lugh »
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micro

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Re: Yagi Antenna modified to become Yagi CANTENNA?
« Reply #15 on: November 09, 2011, 06:34:13 PM »
Yeah, but that one array was for 144MHz as opposed to 2450MHz, I included  the pic mainly as comic relief.
The problem is just that the yagis should be designed with 12.5 ohm or 25ohm impedance for phasing, so that the output would be nice 50ohms.
like 4x 12.5ohms.
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