Wi-Fi Cantenna (dish-tenna) - My experience & problem!

Tantawi · 04-01-2006

Hi all,

From a week ago, me and my friend though about making a wireless network between our buildings, to share files and an ADSL connection. The distance is around 400 meters and there's a diretc line of sight (we are the tallest buildings, although 2.4ghz cordless phones can be found in the middle, is that a problem?)

We spent hours and hours in research, we studied those links:
How To Build A Tin Can Waveguide WiFi Antenna
Waveguide Antenna 2.4 GHz for 802.11b (WiFi) WLAN
And finally: Use a Surplus Primestar Dish as an IEEE 802.11 Wireless Networking Antenna

[The experience]

Hardware used:
1x NETGEAR DG834G V2. - 54 Mbps wirelesss router, ADSL1/2 modem, switch, 802.11g access point, and SPI True Firewall
1x Linksys WMP54G PCI Card

Cantenna components and how we connected it: (we made two exact cantennas).

1- A stainless-steel can (22cm in length, 9cm diameter) connected with N-Female and "F to SO-239" adapter:
http://www.tantawi.net/tabtenna/can....an_connect.jpg

2- The can is connected to 20 meters low-loss coaxial 50 ohm cable (RG-85U), to provide enough cable length from the roof to the router/PC:
http://www.tantawi.net/tabtenna/rg58.jpg

3- The coaxial cable is connected to a WBC-195R pigtail:
http://www.tantawi.net/tabtenna/pigtail.jpg

4- The pigtail cable is connected to the router (and to the PCI card on the other cantenna setup):
http://www.tantawi.net/tabtenna/router.jpg

5- The can is mounted on a 60cm dish put on the roof of the building:
http://www.tantawi.net/tabtenna/dish.jpg

[The results and the problem]

Here's the important stuff, this setup gave 75%-88% signal strength in an indoor test, but when we put it outdoor for real life usage, it doesn't work and the network can't be detected by the client PC. Now the question for cantenna gurus, where's the problem? everything seems perfect! can it be the dish? can cantennas do 400 meters alone without a dish? does a bigger dish make the signal better?

Thanks a lot for any help

Dutch · 04-01-2006

Quote:

Originally Posted by Tantawi

Hi all,

From a week ago, me and my friend though about making a wireless network between our buildings, to share files and an ADSL connection. The distance is around 400 meters and there's a diretc line of sight (we are the tallest buildings, although 2.4ghz cordless phones can be found in the middle, is that a problem?)

We spent hours and hours in research, we studied those links:
How To Build A Tin Can Waveguide WiFi Antenna
Waveguide Antenna 2.4 GHz for 802.11b (WiFi) WLAN
And finally: Use a Surplus Primestar Dish as an IEEE 802.11 Wireless Networking Antenna

[The experience]

Hardware used:
1x NETGEAR DG834G V2. - 54 Mbps wirelesss router, ADSL1/2 modem, switch, 802.11g access point, and SPI True Firewall
1x Linksys WMP54G PCI Card

Cantenna components and how we connected it: (we made two exact cantennas).

1- A stainless-steel can (22cm in length, 9cm diameter) connected with N-Female and "F to SO-239" adapter:
http://www.tantawi.net/tabtenna/can....an_connect.jpg

2- The can is connected to 20 meters low-loss coaxial 50 ohm cable(RG-85U), to provide enough cable length from the roof to the router/PC:
http://www.tantawi.net/tabtenna/rg58.jpg

3- The coaxial cable is connected to a WBC-195R pigtail:
http://www.tantawi.net/tabtenna/pigtail.jpg

4- The pigtail cable is connected to the router (and to the PCI card on the other cantenna setup):
http://www.tantawi.net/tabtenna/router.jpg

5- The can is mounted on a 60cm dish put on the roof of the building:
http://www.tantawi.net/tabtenna/dish.jpg

[The results and the problem]

Here's the important stuff, this setup gave 75%-88% signal strength in an indoor test, but when we put it outdoor for real life usage, it doesn't work and the network can't be detected by the client PC. Now the question for cantenna gurus, where's the problem? everything seems perfect! can it be the dish? can cantennas do 400 meters alone without a dish? does a bigger dish make the signal better?

Thanks a lot for any help

First, do you have a free RF-LOS, and did you do the math ? Please present the Linkbudget and the calculated fresnel zone.

Furthermore, AFAIR RG58U (picture states RG58, not RG85U as you wrote) isn't microwave certified. If that is correctly recalled by me, then with a 20 meter run, I'd think you just negated any and all gain that you might have gotten from the homemade cantenna.

EDIT: Yup, the memorybanks still function. RG58U is rated for frequencies up to 1 Ghz, where the nom. attenuation is 14.5 db/100 feet (33 meters). It would be higher at the 2.4 Ghz that 802.11b/g uses, and staggering at the 5.0 Ghz 802.11a uses.
Datasheet for RG58U : http://bwccat.belden.com/ecat/pdf/8240.pdf
You need LMR 100 or LMR 400 cable for that long a run, when talking WiFi frequencies.

Dutch,

beakmyn · 04-01-2006

RG-58 U is not rated for microwave frequencies. You've got over close to 38dB of attenuation in the cable alone.

http://www.universal-radio.com/catalog/cable/2619.html

MikeP928 · 04-01-2006

And when you get the coax issues worked out, decide which type of antenna you are going to use. The dish is reflecting plenty of signal, but the can of the cantenna is blocking it away from the element. That abortion would be a sumbitch to aim.

Which brings up the next question. After you finished radiating your nuts indoors, how did you adjust the aim?

MikeP

Beard · 04-01-2006

Quote:

Originally Posted by Tantawi

Hi all,

From a week ago, me and my friend though about making a wireless network between our buildings, to share files and an ADSL connection. The distance is around 400 meters and there's a diretc line of sight (we are the tallest buildings, although 2.4ghz cordless phones can be found in the middle, is that a problem?)

We spent hours and hours in research, we studied those links:
How To Build A Tin Can Waveguide WiFi Antenna
Waveguide Antenna 2.4 GHz for 802.11b (WiFi) WLAN
And finally: Use a Surplus Primestar Dish as an IEEE 802.11 Wireless Networking Antenna

[The experience]

Hardware used:
1x NETGEAR DG834G V2. - 54 Mbps wirelesss router, ADSL1/2 modem, switch, 802.11g access point, and SPI True Firewall
1x Linksys WMP54G PCI Card

Cantenna components and how we connected it: (we made two exact cantennas).

1- A stainless-steel can (22cm in length, 9cm diameter) connected with N-Female and "F to SO-239" adapter:
http://www.tantawi.net/tabtenna/can....an_connect.jpg

2- The can is connected to 20 meters low-loss coaxial 50 ohm cable (RG-85U), to provide enough cable length from the roof to the router/PC:
http://www.tantawi.net/tabtenna/rg58.jpg

3- The coaxial cable is connected to a WBC-195R pigtail:
http://www.tantawi.net/tabtenna/pigtail.jpg

4- The pigtail cable is connected to the router (and to the PCI card on the other cantenna setup):
http://www.tantawi.net/tabtenna/router.jpg

5- The can is mounted on a 60cm dish put on the roof of the building:
http://www.tantawi.net/tabtenna/dish.jpg

[The results and the problem]

Here's the important stuff, this setup gave 75%-88% signal strength in an indoor test, but when we put it outdoor for real life usage, it doesn't work and the network can't be detected by the client PC. Now the question for cantenna gurus, where's the problem? everything seems perfect! can it be the dish? can cantennas do 400 meters alone without a dish? does a bigger dish make the signal better?

Thanks a lot for any help

You might think twice about that.

Beard

Dutch · 04-01-2006

Quote:

Originally Posted by Beard

You might think twice about that.

Beard

Good call Beard, overlooked that one.

Dutch

Tantawi · 04-04-2006

Thanks everyone for the reply! Sorry I was away from my PC so I couldn't see or reply you elier!

Well, I'll get LMR 400 cable and see how the things will go, and my ISP here allows line sharing, I've seen networks with 30+ pcs and it's fine, (there's no "home" and "business" seperated plans

Thanks again!

Tantawi · 04-05-2006

Hi guys, my local electonics stores doesn't have LMR-100 nor LMR-400, can you provide any alternatives? I can order online but most "all" online shops don't ship to Egypt :s

And if both are available, which one should I get? LMR-100 or 400?

Thank you.

Dutch · 04-05-2006

Quote:

Originally Posted by Tantawi

Hi guys, my local electonics stores doesn't have LMR-100 nor LMR-400, can you provide any alternatives? I can order online but most "all" online shops don't ship to Egypt :s

And if both are available, which one should I get? LMR-100 or 400?

Thank you.

No alternatives as it has to be rated for microwave frequencies.
LMR400 would be my choice, with the cablerun you are talking about.

Dutch

Airstreamer · 04-05-2006

Quote:

Originally Posted by Dutch

No alternatives as it has to be rated for microwave frequencies.
LMR400 would be my choice, with the cablerun you are talking about.

Dutch

Of course you could go REALLY high $$ and get some Andrew Heliax.

http://www.andrew.com/products/trans...x/default.aspx

04-01-2006	#1 (permalink)
Tantawi Registered Member Join Date: Apr 2006 Location: Egypt Posts: 3	Wi-Fi Cantenna (dish-tenna) - My experience & problem! Hi all, From a week ago, me and my friend though about making a wireless network between our buildings, to share files and an ADSL connection. The distance is around 400 meters and there's a diretc line of sight (we are the tallest buildings, although 2.4ghz cordless phones can be found in the middle, is that a problem?) We spent hours and hours in research, we studied those links: How To Build A Tin Can Waveguide WiFi Antenna Waveguide Antenna 2.4 GHz for 802.11b (WiFi) WLAN And finally: Use a Surplus Primestar Dish as an IEEE 802.11 Wireless Networking Antenna [The experience] Hardware used: 1x NETGEAR DG834G V2. - 54 Mbps wirelesss router, ADSL1/2 modem, switch, 802.11g access point, and SPI True Firewall 1x Linksys WMP54G PCI Card Cantenna components and how we connected it: (we made two exact cantennas). 1- A stainless-steel can (22cm in length, 9cm diameter) connected with N-Female and "F to SO-239" adapter: http://www.tantawi.net/tabtenna/can....an_connect.jpg 2- The can is connected to 20 meters low-loss coaxial 50 ohm cable (RG-85U), to provide enough cable length from the roof to the router/PC: http://www.tantawi.net/tabtenna/rg58.jpg 3- The coaxial cable is connected to a WBC-195R pigtail: http://www.tantawi.net/tabtenna/pigtail.jpg 4- The pigtail cable is connected to the router (and to the PCI card on the other cantenna setup): http://www.tantawi.net/tabtenna/router.jpg 5- The can is mounted on a 60cm dish put on the roof of the building: http://www.tantawi.net/tabtenna/dish.jpg [The results and the problem] Here's the important stuff, this setup gave 75%-88% signal strength in an indoor test, but when we put it outdoor for real life usage, it doesn't work and the network can't be detected by the client PC. Now the question for cantenna gurus, where's the problem? everything seems perfect! can it be the dish? can cantennas do 400 meters alone without a dish? does a bigger dish make the signal better? Thanks a lot for any help Last edited by Dutch : 04-01-2006 at 02:35 PM. Reason: Embedded pictures changed to links. Read the rules in the welcome desk section.

04-01-2006	#3 (permalink)
beakmyn Free Public Wifi Join Date: Aug 2003 Posts: 4,992	RG-58 U is not rated for microwave frequencies. You've got over close to 38dB of attenuation in the cable alone. http://www.universal-radio.com/catalog/cable/2619.html __________________ ┌──────────────────────────────┐ ╞ NS Icons Explained\|et hoc genus omne ╡ └──────────────────────────────┘ Creating yesterday's future, Today! Last edited by beakmyn : 04-01-2006 at 03:17 PM.

04-01-2006	#4 (permalink)
MikeP928 Heeere's your sign! Join Date: May 2002 Location: Mexico Beach, FL Posts: 1,169	And when you get the coax issues worked out, decide which type of antenna you are going to use. The dish is reflecting plenty of signal, but the can of the cantenna is blocking it away from the element. That abortion would be a sumbitch to aim. Which brings up the next question. After you finished radiating your nuts indoors, how did you adjust the aim? MikeP __________________ Democracy is two wolves and a lamb voting on what to have for lunch. Liberty is a well-armed lamb contesting the vote. -- Benjamin Franklin, 1759

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04-04-2006	#7 (permalink)
Tantawi Registered Member Join Date: Apr 2006 Location: Egypt Posts: 3	Thanks everyone for the reply! Sorry I was away from my PC so I couldn't see or reply you elier! Well, I'll get LMR 400 cable and see how the things will go, and my ISP here allows line sharing, I've seen networks with 30+ pcs and it's fine, (there's no "home" and "business" seperated plans Thanks again!

04-05-2006	#8 (permalink)
Tantawi Registered Member Join Date: Apr 2006 Location: Egypt Posts: 3	Hi guys, my local electonics stores doesn't have LMR-100 nor LMR-400, can you provide any alternatives? I can order online but most "all" online shops don't ship to Egypt :s And if both are available, which one should I get? LMR-100 or 400? Thank you.