I need to link two LANs on a farm that are about 1500-2000 feet apart.
I've got line-of-sight (or can, once I prune a couple of trees).
Can anyone recommend a good wireless bridging solution? It's mostly to share internet access, so I don't really need to go much faster than few megabits per second. I know there's all sorts of pringle-can type solutions but I'm looking for something out-of-the box.
The solution also needs to be fairly robust so I don't have to climb up a ladder every day to reboot it or re-align a transceiver :)
You may need to do more than prune. You need what is called Fresnel Zone clearance. At 2000ft, that's about 12 ft from the center line at midpoint. See:
your Fresnel Zone hits the ground, trees, or other obstructions, you will have signal loss, edge diffraction, and a generally flakey signal.
Well, I'll assume that the remote end will have more than one computah and will therefore require a transparent bridge. If there's only one computah at the remote end, it might be easier and cheaper to use a client radio and antenna, instead of a transparent bridge.
Well, with a fairly generic 10dBi antenna, you'll have a -3dB (half power) beamwidth of about 30 degrees. Alignment isn't all that critical until the gain goes above about 15dBi. By the time you get to a 24dBi dish, you're looking at 5-7 degrees beamwidth, which is really difficult to align and keep aligned in the wind.
I suggest: |
is a combination antenna, radio, PoE (power over ethernet), all in one package. They're 802.11b not g so you'll get about
3.5Mbits/sec thruput maximum. It's quite a bit more expensive than commodity solutions, but you didn't specify a price limit. If this is too expensive, set a limit and I'll what can be thrown together, err... engineered.
Also, there have been reports of some problems with Tranzeo hardware. Search Google Groups in alt.internet.wireless for comments on these. I've only installed two links with these and had no problems.
Incidentally, I did a quick calculation of the minumum antenna gain you'll need at 2000ft with commodity hardware (+15dBm tx output).
11dBi antenna gain at each end is the theoretical minimum. If you build your own, you'll need to know this.
How about starting a new thread next time you change the subject?
I've been trying to sell the local ISP's into providing 900MHz service in the forests of Santa Cruz mountains. The idea is to provide low speed service sufficient to run a slow (about 60Kbits/sec thruput) internet connection or a single VoIP channel. There's some small interest, but most users demand broadband. I had quite a bit of experience with 900MHz propogation dealing with Metricom (Ricochet) and Waverider modems. They work just fine but note that they were mostly 1watt (+30dBm) radios. Basically, they go right through the trees.
You can sometimes find a pair of the old Metricom modems on eBay. They'll talk to each other point to point at about 25Kbits/sec thruput. Range varies with antennas, but a mile with a pair of small circuit board yagis is no big deal.
Incidentally, the Peoples Republic of Santa Cruz County has a 900Mhz data system used to replace the phone lines used by the State Lottery machines. You can see the yagi antennas at many local gas stations and convenience stores.
There are a bunch of different types of 900MHz radios available. Which one are you referring to?
Jeff on this subject, if thru put over the net connection doesn't have to be 'all that high' how well do these 900Mhz devices you see on the net work? For moderate distances again where you are say trying to network at 'better then dial-up' is this a viable option? Seems like at 900Mhz, you have a more robust signal though at a price of lower bandwidth.
None in particular, the reason I didn't alter the subject, was the question was about bridging 2000 feet. There are as you noted in other posts in this thread issues with that distance at 2.4Ghz. I was just wondering if one can live with a reduced thruput if one of the 900Mhz systems would get the job done for a half mile to a mile or so.