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Wide Area Wireless on a Shoestring Budget?
wkytechhead asks: "My father owns a greenhouse operation that covers a few dozen acres. He has a number of greenhouses some up to 1000' plus apart that he would like to network. Currently he is using a HomePNA based network via regular RJ12. He has decided that he would like to go at least partially wireless. Some consideration has been given to using the backbone with fiber convertors, but he would really like to do full wireless. I have checked into homemade and commercial 'Cantennas' but I am not sure if they are worth the money. How would my fellow geeks go about wirelessly networking a large outdoor area for as cheap as possible?"
I agree.
Since you own all the pieces, and the traffic isnt high unless you plan to stream videos from your plants, go wireless mesh. Properly setup, this would actually be a more robust setup.
I wonder if you could also do a whole bunch of p2p connections and run BGPv4 over it. Will look great over your resume.
"Give orange me give eat orange me eat orange give me eat orange give me you." -Nim Chimpsky
www.trevormarshall.com/waveguides.htm He explains the how and why, so you cab build a 180 degree waveguide.
Cantennas are the wrong way to go, as their propagation pattern approximates linear, like the yagi designs. What you want is an omni, sometimes called marine, antenna that will spread signal in a plane. If you're in a greenhouse, I'm assuming you don't want strong signal going up or down, but horizontal in the plane of people walking around. Here's an example of one I grabbed from Google: radiolabs omni antenna For about another $30 you can pick up pigtails on eBay that let you attach these to the usual netgear/buffalo/d-link/linksys/etc. accesspoints. You can place them for effective 10Mbit coverage about one for every 2 acres assuming clean line of sight to the antennas and no major obstacles. Note that vegetation would definitely impact signal propagation in the 5.4ghz band.
http://tinyurl.com/4ny52
At my place of work, we have a wireless backbone that links over 16 miles. When one of our primary units went down due to a lightning problem, we constructed a cantenna and pointed it at the remote ap. The backbone was linked up once again and it worked great! We eventually replaced the redundant link with a 24dbi parabolic, but it's worth the small amount of time to check out the cantenna solution, as it's significantly cheaper than the parabolics.
You'd be suprised the kind complaint they respond to. My house used to have a very large antenna for TV(35 foot I think) because we were on the dark side of a mountain and couldn't recieve a signal from NYC. We also had a special motorized/pointable CB antenna. The guy next door, instead looking at the mountain and thinking, "hey the only reason they can a signal is because they have a giant antenna" thinks "hey they are plotting against me, and blocking my signal"
The FCC actually came and did tests, said that was silly and went home.
=1000101
out.
-- DrZaius - Minister of Sciences and Protector of the Faith
This isn't a new concept.
In fact, you can attempt to order an alarm circuit or dry copper pair from your telephone company. If you manage to get it and they don't have a filter in place you can slap on two dsl modems for a low cost high speed leased line.
I've had co-workers buy their telco guys beers to have the filter removed.
"You should always go to other people's funerals; otherwise, they won't come to yours." -- Yogi Berra
Where do you live? There are lots of the 24dbi antennae on roofs around here (Oklahoma) left over from a wireless cable company bankruptcy. I think the price is probably free if you don't mind crawling on a roof to go after them. I doubt that the bankruptcy lawyers will fight you for them. They probably don't know they exist or if they know, don't care. I understand they may need some minor tuning to work with 802.11b. kk
A friend pointed the site out to me about a week before it hit slashdot, so by the time the original story broke here, I had built one.
Long story short. They work really well. I've pwned every wireless access point within a 3Km radius of my house. Free Internet anyone? :-)
I find your ideas intriguing and I wish to subscribe to your newsletter.
Linksys Access Points are based on linux and they opened up the firmware under the GPL. Several groups have released modified firmware, Sveasoft is just one of them.
I have 2 linksys WRT54G access points in my house. Only one of them is plugged in to the cable modem. The other connects back wirelessly over WDS. I can connect to the internet from either of them.
One of the best things things is that they allow you to crank up the transmit power.
If I were you, I'd get a few of these things...get a couple of high gain antennas and set up a WDS network. Completely wirelessly...