Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronic Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

Directional Antenna at 2.4GHz

Status
Not open for further replies.

techie

Advanced Member level 3
Joined
Feb 5, 2002
Messages
839
Helped
58
Reputation
116
Reaction score
9
Trophy points
1,298
Location
Pakistan
Activity points
7,799
homemade 2.4 ghz corner reflector

How can I make a directional antenna for 2.4GHz. The application is to extend the range of a 802.11 ehternet bridge. The bridge has monopole antenna and has a range of 300m. I wish to increase this range in one direction to about 1km.

Is it at all possible
 

flatulent

Advanced Member level 5
Joined
Jul 19, 2002
Messages
4,629
Helped
489
Reputation
980
Reaction score
150
Trophy points
1,343
Location
Middle Earth
Activity points
46,689
40 db antenna gain

You will need about 20 dB of antenna gain at each end. The D-Link company and others sell high gain antennas of this value. They should not have any obstructions between them like walls or buildings.
 

Pingy

Junior Member level 1
Joined
Nov 30, 2001
Messages
18
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Location
Spain
Activity points
93
Hi Techie,

You can make yourself the antennas, it is not difficult. A 60 cm dish, like
the ones used for TV-SAT will give you the right gain at the 2.4 GHz
frequency. Of course there are other antennas that could be used as well.

Regards

pingy
 

OvErFlO

Full Member level 3
Joined
Dec 7, 2001
Messages
178
Helped
7
Reputation
14
Reaction score
3
Trophy points
1,298
Activity points
1,356
I have create a dish antenna with a Vsat dish and a pringles like feed. I have buy a dish gregorian (24dB).
With this two antenna I have do 9Km with -62dB of signal... With two dish antenna it's possible a 35Km connection...
 

flatulent

Advanced Member level 5
Joined
Jul 19, 2002
Messages
4,629
Helped
489
Reputation
980
Reaction score
150
Trophy points
1,343
Location
Middle Earth
Activity points
46,689
general rules

The general rule for over the horizon smooth earth ground wave path is 20 dB more total system gain for doubling the range. For line of sight it is 6 dB.

Line of sight includes reflections from large objects like building walls and mountains although these have a reflection loss that is fixed in value for a give path.

802.11 uints have a wide variation of output power. Plug in cards for computers are 10 mW and some box units are 100 mW while the legal limit in some parts of the world is 1 W.


You can get another 10 dB improvement by cutting the bit rate back to the lowest rate.
 

Lupin

Full Member level 6
Joined
Jan 22, 2003
Messages
342
Helped
12
Reputation
24
Reaction score
9
Trophy points
1,298
Location
Italy
Activity points
3,235
What about a planar array of patch antennas? You can reach a Gain of 25-30 dBi.. What do you think? Is your antenna for a WLAN application isn't it?

Regards
Lupin
 

techie

Advanced Member level 3
Joined
Feb 5, 2002
Messages
839
Helped
58
Reputation
116
Reaction score
9
Trophy points
1,298
Location
Pakistan
Activity points
7,799
Thanks guys. As I mentioned, my application is purely hobby. As my office is in line of sight 1km from my home, I want to bridge the LAN there with my home PC without spending too much money. Data rate is not an issue.

Pingy & OverFlow, can you shed some light on how to make the 60cm dish, what kind cable to use from the 802.11 transciever and how to terminate it at the dish. Although I did study electromagnetic in EE, this is not my field. Any novice design examples avaialable on internet or if possible, can you give some guidance,

thanks
 

Pingy

Junior Member level 1
Joined
Nov 30, 2001
Messages
18
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Location
Spain
Activity points
93
Hi Techie,

A link over a 1km distance should be piece of cake. You can find
information on the web from people who made antennas for the
2.4 GHz band. Here are some examples:

h**p://www.qsl.net/ki7cx/wgfeed.htm
h**p://www.qsl.net/kc2hax/ant/feedhorn.htm
h**p://www.xyz.net/~joe/OSCAR3.html
h**p://lea.hamradio.si/~s51kq/ANTENNA.HTM
h**p://www.ultimatecharger.com/Dish_Feed.html
h**p://www.qsl.net/wk8l/

For the cable I recommend to use a good coaxial. The cable used for the
SAT-TV dishes (75 ohm) is cheap and good enough for this aplication.

Good luck

pingy
 

techie

Advanced Member level 3
Joined
Feb 5, 2002
Messages
839
Helped
58
Reputation
116
Reaction score
9
Trophy points
1,298
Location
Pakistan
Activity points
7,799
Thanks a million Pingy. These look easy to make antennas. You mentioned that achieving a 1km range should be a price of cake. Do you think connecting this parabolic antenna to the following device

h**p://w*w.linksys.com/products/product.asp?grid=33&scid=36&prid=432
Linksys-Wireless ethernet bridge WET11.
will increase its range from the mentioned 300m to above 1km.

Obviously I intend to use two of these devices with two parabolic dishes.[/url]
 

Pingy

Junior Member level 1
Joined
Nov 30, 2001
Messages
18
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Location
Spain
Activity points
93
Hi Techie,

I had a look at the devices you tell me and they look similar to the Avaya
systems we are presently using over a 800 m distance. I am convinced
you can easily reach well over the km range with two such devices
connected to the 60 cm parabolic dishes.

Regards

pingy
 

techie

Advanced Member level 3
Joined
Feb 5, 2002
Messages
839
Helped
58
Reputation
116
Reaction score
9
Trophy points
1,298
Location
Pakistan
Activity points
7,799
Pingy, you mentioned Avaya systems. Is that also for wireless networking. Becasue if you have already done building LAN bridge, probably you can also guide a better 802.11 brdge. Have a look at the

h**p://w*w.dlink.com/products/wireless/dwl810+/

Is this a better device than the WET11 I mentioned before

thanks,
techie
 

Pingy

Junior Member level 1
Joined
Nov 30, 2001
Messages
18
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Location
Spain
Activity points
93
Hi Techie,

Yes you are right, this type of device is twice as fast as the Avaya link
we are currently using. I didn't know about this 22 Mbits/s range of
products. Thank you for the information.

Regards

pingy
 

techie

Advanced Member level 3
Joined
Feb 5, 2002
Messages
839
Helped
58
Reputation
116
Reaction score
9
Trophy points
1,298
Location
Pakistan
Activity points
7,799
Yes Pingy, this device is at 22Mbps. But do you think this is better than the Linksys wet11 as far as range is concerned. It says 400m against 300m of linksys. Frankly speed is not important. I can handle even 5mbps if range is OK.

How about the Avaya solution that you are using. Can you shed some light on that. What model did you use and how much range enhancing did you achieve. The antenna type etc. Any other practical problems here.

thanks

techie
 

techie

Advanced Member level 3
Joined
Feb 5, 2002
Messages
839
Helped
58
Reputation
116
Reaction score
9
Trophy points
1,298
Location
Pakistan
Activity points
7,799
Another product from D-Link is DWL-900AP+. This being another 22Mbps product looks much better than the DWL-810+. What do you think of it.
 

Compy

Member level 2
Joined
Jan 24, 2005
Messages
53
Helped
2
Reputation
4
Reaction score
1
Trophy points
1,288
Activity points
454
if i use Dish antenna of digital receivers.. to send signal.. what module will i use to send signal.. LNB will be compatible for 802.11g
thanks
 

Jerzyg

Newbie level 5
Joined
Jan 17, 2004
Messages
8
Helped
1
Reputation
2
Reaction score
0
Trophy points
1,281
Activity points
91
techie said:
How can I make a directional antenna for 2.4GHz. The application is to extend the range of a 802.11 ehternet bridge. The bridge has monopole antenna and has a range of 300m. I wish to increase this range in one direction to about 1km.

Is it at all possible
The simplest and chaepest test would be to place your monopole/dipole antenna in a 90 degree corner reflector. In order to keep your matching separate your monopole by 0.37λ from the vertex. This will increase your gain from around 2dBi to 10-12dBi. The bigger reflector you use the better, but reasonable size of walls should be around 1λ width and 2λ high.

Regards,
Jerzyg
 

creative_35

Full Member level 1
Joined
Apr 10, 2006
Messages
95
Helped
9
Reputation
18
Reaction score
3
Trophy points
1,288
Location
Under Mango Tree
Activity points
2,031
Hi friends,
How do I check the gain of an antenna? I don't have a laptop. can I use wireless LAN card + wireless access point in same PC and measure (Compare) the gain of my home made antenna with netstumbler? ( I never used netstumbler before). Is there any other way to check the gain and VSWR? ( I have no equipments except a digital multi tester)
 

Status
Not open for further replies.
Toggle Sidebar

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top