Wouldn't too small a diameter create a wave guide *above* cutoff? Or am I missing something.. My can is about 3.5" wide, making the theoretical cutoff right around 2500MHz. Do you think a smaller can might work better? ----- Original Message ----- From: "David VanHorn" To: Sent: Monday, August 02, 2004 12:58 AM Subject: Re: [OT:] WIFI Waveguide antenna > At 11:50 PM 8/1/2004, Robert B. wrote: > > >Has anybody had experiences with homebrew wifi antennas? I built one this > >evening similar to the "cantenna" described in various places on the web, > >and it works OK, but not up to the level I was hoping for. > > > >The cantenna is located in a room separate from the desktop PC which gets no > >wifi signal at its manufacturer-supplied omni-antenna. The laptop (built-in > >wifi) picks up a strong signal where the cantenna is located, but the > >desktop hooked to the cantenna in the same location picks up a very weak > >signal (~-85db snr). I used about 15 feet of standard coaxial cable as the > >antenna line.. anybody know how to figure the theoretical signal loss > >through it? I'm not sure but I doubt coax was designed for 2ghz+ > >frequencies. Does anybody know for certain? > > Most of the antennas I've seen have used cans that are too small a diameter. > "Waveguide below cutoff". Also, most small coax is pretty lossy at 2.5 GHz. > I've used RG-174 at 1.5 GHz for GPS, but not more than about 10', and with an amplified antenna. > > Look at ham designs for antennas in the 2.3 GHz band and just scale it smaller a bit. > > -- > http://www.piclist.com#nomail Going offline? Don't AutoReply us! > email listserv@mitvma.mit.edu with SET PICList DIGEST in the body -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body