Best antenna for wireless point-to-point bridge

[mrcoolio01]

Hi all,

I am trying to get a wireless point-to-point bridge set up between the roofs of 2 buildings using 2.4GHz 802.11g. The buildings are about 200 ft apart, and on the roofs there is a clear line of sight between them. I would like the wireless connection to be directional for a number of reasons (more secure, stable, fast, free of interference). I have already determined which pair of bridges to use (Buffalo WHR-HP-G54). However, I am totally lost when it comes to antennas.

1) How much antenna gain do I need to get a SOLID connection? Is 14dBi enough?

2) What type of antenna should I use that's best for my application (yagi, patch, grid, etc.)? All the retail companies (trendnet, hawking, smc) seem to like patch antennas a lot, but I found grid antennas selling for cheaper on some websites.

3) Do I need to buy 2 antennas and point them towards each other, or can I get 1 external antenna and point it towards the built-in omni antenna of the other bridge?

Thank you

[golfnut]

At 200 ft, 14dbi is plenty and you would need two panels, one on each end however, fast and free of interference is not a result of the antenna type.

Increasing the gain or distance of the signal also increases the ability of the radio to hear other 802.11 b/g networks and this interference can affect speed, distance, and the stability of the link.

You might consider using 802.11a radios for the bridge link. If there's a lot of 802.11b/g interference, 802.11a can actually travel a lot further and maintain a better link. If this is a business type environment, consider purchasing a device specifically for bridging (i.e. Proxim or Cisco).

You'll also want to align the antenna's for the best possible throughput. An easy way to do this is to set a static IP on both radios. Run a continous ping test from one end to the other. Adjust your antenna's until the ping times are at the shortest amount of time. Higher-end bridges will have a utility to help do this.

Greg

[umdivx]

I am a fan of these for point to point setups: http://www.wlanparts.com/product/EOC-3220

- Josh

[joshb14]

Very nice info.

Thanks!