On Thu, 9 May 2002, Mike Bresnahan wrote: > I'm very new to this wireless stuff and have never played with radio > equipment beyond Citizen's Band (CB radio), but I know enough to have > a couple questions about the range of 802.11b. > > What little I have read about 802.11b and its counterparts (e.g. > bluetooth wireless) discusses effective ranges of 10-100 meters. My > limited experience with my Linksys Prism2.5 card confirms this range. > How is it that people on this list are discussing ranges upwards of 23 > miles? Perhaps the stuff I have been reading assumes very small > antennae? Yup -- it assumes the built in rubber duckies, which generally have a gain of 0 dBi to 2 dBi. You can get antennas that do 24 dBi for < $100. Remember, dBi isn't a linear scale -- every 3dBi of gain effectivly doubles your power (iirc). > After seeing the coverage maps of the Twin Cities displayed at the > meeting, I'm left with some confusion. What good is it to put up a > big antennae backed by a big amplifier and coat a very large area with > 802.11b? Can people with ordinary WLAN cards in their laptops > actually communicate with the access point? I can understand how they > might be able to recieve data, but how can they hope to transmit over > such a large distance with their wimpy amplifier and antennae? Do you > need a big antennae only on one end to make it work? Depends on how far out you are. Often, yes, you will need an antenna to communicate back. But, it's not really that expensive.. $80 for a card with an external antenna connector and a pigtail, $50 for misc cables, $75 for a lightning arrestor, $50 for a tripod and ground strap, and $75 for an antenna.. not cheap, but not insane, especially if you're planning on getting 'net access through it (can buy this instead of a cable modem or dsl router). -- Nate Carlson <natecars at real-time.com> | Phone : (952)943-8700 http://www.real-time.com | Fax : (952)943-8500