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I've used those. They work good but they're a little unwieldy, and probably overkill in this case. (I used a pair of 24dbi parabolics once to test a 5 mile link. It worked, but thoughput wasn't great. In retrospect, the link may have been degraded by the tinting of the window I was transmitting through at one end.)

I've also used panel antennas from superpass, many of which have smaller sidelobes than the parabolics, and are smaller and (usually) cheaper.

At 1000', you might not even need directional antennas (if you have good wireless cards), or you might get away with a directional at only one end.

Try looking at hyperlink, superpass, and netnimble for comparison.

-jim

Check out these antennas. I've had good luck with the few that I've purchased. Be sure to get antennas with the same polarization (horizontal or vertical) -- it makes a big difference in signal strength to have similar polarization!

If your bridge supports antenna diversity (like the wap11 does) maybe it would be helpful to use two yagis, parabolic grid or dish antennas (directional, tightly focussed), one for each site. If you use an omnidirectional antenna for the most central site, you'll probably be wanting directional antennas at the other sites to increase the gain.

If the sites are all within (180/120/90/60/45 degrees), instead of an omnidirectional you could use a panel antenna which covers a limited angle (superpass make them - maybe worth asking them what they'd suggest).

Also it might be worth knowing that most directional antennas have sidelobes where they are also sensitive, albeit at a lower gain. This often isn't particularly useful, but who knows, you might be lucky with positioning of sites :)

Decent suppliers/manufacturers should include a plot of the radiation pattern of their antennas with the description.

Here are some URLs you might find interesting: HPWREN (featured here recently) have a 45mb backbone using western multiplex tsunami kit, and 802.11b access points. They use solar power and batteries to power some backbone nodes.

Some other people using mostly 802.11b kit who will have some information you can use: BAWUG PersonalTelco.net NoCat.net Freenetworks.org

Using 802.11b or similar tech, you should expect each wireless hop to add about 5ms of latency, maybe a little more depending on distance. You can quite easily build a repeater by connecting two bridges together by a X-over cable. You could probably do this with Linksys WAP11 or similar, but over this type of distance you will find it much easier to use something like the high-spec version of Cisco Aironet 350 bridges (the 100mW versions will push the signal a lot further - 25 miles with 24dBi antennas - you can use Cisco's own, alternatives include Superpass (based in Waterloo), HyperLinkTech and others.

Aironet bridges let you set the distance of the link which modifies timing parameters (a slight problem with standard 802.11b over long distances), and their security is better than WEP.

There's plenty of homebrew opportunities for antennas and other related kit, although I guess they're probably of more use to people who don't have a budget to play with (: There's a collection of links on this page with a particular focus on homebrew kit.

Great input. Thanks, Kevin42 (would you believe that up until today I
thought that multipath was a psychopath with a twin brother?!?).

Seriously though, apart from being a cheapskate, one of the things
which has kept me from buying (or building) a "real" antenna is the
problem of interfacing it to the wireless card. Does anyone know where
to pick up reasonably priced pigtails (on the web) for Buffalo, Corega
or GeoWave cards? They don't seem to be very easy to come by here in
Japan and the ones I've found on the web so far were twice the price of
a 7dbi antenna from someone like SuperPass.

http://www.ydi.com
http://www.netnimble.com/products/index.html
http://www.superpass.com/

HTH! :-)