bfin2,
"dbi" is a measure of the gain of antenna. The gain of antenna tells
you how good it is at picking up a radio signal.
You can find a more technical definition of "dbi" at the following
locations:
NetWORLD Wireless Antenna Glossary
http://wireless.networld.com/antennas/glossary.cfm
Panorama Antennas: Glossary (more technical)
http://www.panorama.co.uk/Technical_Help/glossary%20of%20terms.html#gain
A higher "dbi" means the range of the antenna will be better.
A common method of increasing the "dBi" of an antenna and therefore
its range is by making the antenna directional, so it only receives
signals in specific directions.
Just as somone who is hard of hearing may cup their hand to their ear
to block out background noise and hear better, a directional antenna
blocks out background noise and only listens in a specific direction.
For example, one can use a pringles can to make a very cheap
directional antenna that could transmit a WiFi signal for 10 miles or
so at 11mbs.
O'Reilly Network (scroll to bottom)
http://www.oreillynet.com/cs/weblog/view/wlg/448
You can also buy these types of direction antenna's commercially for
$150 - $300 depending on the quality of the antenna.
HyperGain
http://www.hyperlinktech.com/web/antenna_kits.html
NetNimble
http://www.netnimble.net/
Directional antennas work best if you are trying to connect two
locations over a long (5-10 mile distance). They also work better when
you have line of sight, a large building between the two antennas will
reduce the distance the signal will travel.
Other factors such as the hight of the antenna, its size and so on all
affect the range of the antenna.
Since it takes some specialized knowladge to get up and running with a
10 mile link, you may want to consider talking to others who are
working on the same thing. There are a number of user groups around
the country with folks who have experience.
The Bay Area Wireless Users Group is one of the larger such groups:
http://www.bawug.org/
A few of their members have a guide to setting up a long range
wireless link which you may find useful:
http://www.bawug.org/howto/pres/20010503/
To summerize:
You can extend your wireless range in one direction by purchasing or
building one or two directional antenna's and pointing them at each
other. When purchasing an antenna, the higher the dbi the better the
range. Since this area of wireless connection is still developing you
may want to talk to someone who has set up a long distance link before
trying it yourself.
Hope this has helped answer your question,
Dynamo-ga
Search terms used
+antennas +wifi +long +distance
+dbi +glossary +antenna |
