Wide Area Wireless on a Shoestring Budget? 239
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?"
24dBi Point To Point Antennas for around $55 each (Score:5, Informative)
Re:24dBi Point To Point Antennas for around $55 ea (Score:2, Informative)
Re:24dBi Point To Point Antennas for around $55 ea (Score:2)
Re:24dBi Point To Point Antennas for around $55 ea (Score:4, Informative)
You should be able to deal with minor tree obstruction.
Re:24dBi Point To Point Antennas for around $55 ea (Score:5, Informative)
Use a link budget calculator [ecommwireless.com]. (The link is one I just found with google).
Basically, you need a certain signal to noise ratio for a digital radio connection to work at all at its lowest speed. Increased signal to noise ratios get you more speed and some margin of reliability.
Signal decreases with the square of the distance. If you double the distance you'll have one quarter the signal, or 6db less (decibels are logarithmic - 3db is a ratio of 2, 10db is a ratio of 10). So, everything else being equal, you'd need 6db more gain on the antenna at either end to get the same results.
For your particular scenario you'd probably be fine with just a couple cantennas or other moderate-gain antennas.
One thing to watch out for when shooting through trees is that they may not have leaves now but they will in a few months!
Re:24dBi Point To Point Antennas for around $55 ea (Score:2)
I've used those. They work good but they're a little unwieldy, and probably overkill in this case. (I used a pair of 24dbi parabolics once to test a 5 mile link. It worked, but thoughput wasn't great. In retrospect, the link may have been degraded by the tinting of the window I was transmitting through at one end.)
I've also used panel antennas from superpass [superpass.com], many of which have smaller sidelobes than the parabolics, and are smaller and (usually) cheaper.
At 1000', you might not even need directional
Re:24dBi Point To Point Antennas for around $55 ea (Score:5, Informative)
"2.4 ghz parabolic antenna"
Lowest price is around 33$ for a 15dbi gain. 50$ is about right for a 24dbi gain. Though a parabolic is only going to be truly handy for sight to sight. They do have low cost omni directional antennas. This is difficult to advise without knowing the layout.
ie, possibly sight to sight parabolic for the backbone link and then omni's distributed throughout.
If you are really worried about distance, just dig up a router that can be tweaked for a bit more output power.
Now, if completely unsure of what your needs are, here is a handy calculator to help you figure your distance needs out.
http://www.signull.com/fsc.php
For the uninformed, cable loss is going to be calculated by the amount of signal loss expected when using some portion of cable from the transciever to the antenna. It should be expressed quite clearly on type of cable you are going to be using.
There are also some common models output numbers listed there as well.
That really sums up everything. It should be quite cost effective to implement a few antennas and a cheap 802.11b setup.
Re:24dBi Point To Point Antennas for around $55 ea (Score:2, Interesting)
Re:24dBi Point To Point Antennas for around $55 ea (Score:5, Informative)
Still, they will work just fine, with some gain loss...
Here is a smaller article on the matter... to adapt one. (kinda helpful if you really really don't know what you are doing)
http://www.qsl.net/n9zia/wireless/page04.html
Why pay USD$55.00 when you can pay AUD$5.00... (Score:5, Interesting)
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? :-)
Re:Why pay USD$55.00 when you can pay AUD$15.00... (Score:2)
Re:24dBi Point To Point Antennas for around $55 ea (Score:2)
You are stuck if you order the wrong one. I nearly got burned buying from them. I never did get the lightning arrestors to work properly, they just degraded range and signal quality unacceptably for reasons I can't figure out.
Re:24dBi Point To Point Antennas for around $55 ea (Score:3, Informative)
Wireless LAN's End to End
and
Wireless Networks The Definitive Guide
are both excellent books that clearly explain the issues involved with DESIGNING a wireless network.
A +24dbi parabolic dish is more than innappropriate for what you are doing, so is running firmware hacks to "Pump Up Your Power".
It's not about how much signal you can irradiate the land with, it's about placement and antennae with the correct signal pattern.
Re:24dBi Point To Point Antennas for around $55 ea (Score:4, Informative)
So, the limit is 30 dbm (1000 milliwatts), most wireless cards are about 15dbm, which gives us 15 dbm of slack. 24dbi exceeds 6 dbi by 18, so this would be illegal for a point-to-multipoint topology. However, if it was a point-to-point link, that 18dbi of excess gain results in a reduction of only 6dbm of permitted power, so you could use a 24dbm radio (or a little over 200mw) legally. (Though ianal or an rf engineer, so take this with a grain of salt.)
Re: (Score:2)
Re:24dBi Point To Point Antennas for around $55 ea (Score:2)
You are not going to get the full 15dbm to the atenna. There will be some loss and having a little head room isn't a bad idea.
That being said... it's a farm... no one is going to complain to the FCC.
DSL (Score:5, Informative)
Otherwise, run ethernet?
if you are going to go wireless, get some good APs and sector antennas, or alternately setup a bunch of repeater stations that use different channels to avoid interference.
Re:DSL (Score:2)
unfortunately, (Score:2)
Re:unfortunately, (Score:3, Informative)
Re:unfortunately, (Score:2)
Re:unfortunately, (Score:3, Interesting)
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.
It wasn't a new concept... (Score:2)
This is the first time I've heard that it was possible with DSL. Please give us more details.
You could also buy a DSLAM. I've got a used CopperEdge I'd like to get rid of. 24 IDSL ports and 24 SDSL ports, routeable from the ethernet jack on the front.
Re:unfortunately, (Score:2, Informative)
Re:DSL (Score:2)
Thanks for trying though.
My guess is he wants 1 box and 2-5 BIGASS antennas to just swath his plants with radio waves.
Or maybe he wants to see someone's crazy hack of some sweet ass 5 foot antenna that looks like an x-wing and has 5 miles of range.
Re:DSL (Score:3, Informative)
this by no means requires any computers at all. I saw an article a while ago about a golf course that did this- they had a shelf of 8 $89.95 Cisco DSL modems (all set in 'server' mode) at their datacenter, linking to offsite signs around the course. Each sign had another dsl modem, operating normally. The only wiring they did was to run each sign a dry pair, and plug the modem to the sign's Ethernet controller.
Re:DSL (Score:4, Interesting)
out.
Minidishes (Score:5, Informative)
Re:That's illegal in the US (Score:5, Informative)
Re:That's illegal in the US (Score:2)
Re: It's not like anyone CHECKS (Score:5, Funny)
Re: It's not like anyone CHECKS (Score:4, Funny)
Re: It's not like anyone CHECKS (Score:4, Interesting)
The FCC actually came and did tests, said that was silly and went home.
Re: It's not like anyone CHECKS (Score:2, Insightful)
no necessarily cheap (Score:2)
Re:no necessarily cheap (Score:5, Informative)
Is a WiFi antenna howto and I build the can-waveguide out of two tomato sauce cans with an N connector. It totaled to about 5 bucks worth of parts and works very well. The tuning for it though might be off and I hand redid with a sheet metal snipper.
This is cheap, simple, not illegal.. (Score:2)
http://www.belkin.com/networking/
Belkin's Pre-N Wireless supposedly has 800% wider coverage and is totally affordable. It might not be what the stand ends up being in the future, but hey, as a totally proprietary system it looks to kick butt!
Re:no necessarily cheap (Score:3, Interesting)
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.
Look into a mesh network (Score:3, Informative)
See http://www.oreillynet.com/pub/a/wireless/2004/01/
That's not going to be easy (Score:5, Informative)
Re:That's not going to be easy (Score:4, Informative)
Cows (Score:5, Funny)
Problem solved
Re:Cows (Score:3, Funny)
-Ab
Re:Cows (Score:2)
Re:Cows (Score:2)
Oh sure, that'll give the locals easy targets to tip over. Of course, you're probably not using the network at night
Re:Cows (Score:2)
sounds like a plan... (Score:3, Funny)
building your network (Score:4, Funny)
Re:building your network (Score:4, Funny)
Re:building your network (Score:3, Funny)
I can see the benifit. So much faster to ping a bottle to see if it's corked or not. No more wasted trips to the cellar. You better be careful and block port 25 from you cellar... some of those Brazil wines are known spammers.
WDS (Score:2, Insightful)
Then, spread them evenly. I'm sure it'd work famously.
1000' = No Problem (Score:3, Informative)
If all of these sites are within a mile with reasonable line of sight and not many trees in the way, I'd suggest putting the parabolic antennaes at each location directed toward your main location.
At the main location go with a nice sector antenna array.
Heres a link:
http://squitter.com/products/antennas/parabolic24
Homebrew your AP and end nodes with a workstation or soekris board and a netgate radio...or connect the antennas to commercial AP/Bridge units.
Depending on how many sites you have to link, you should get out at a reasonable cost.
5.5 statute miles no problem. (Score:2)
Visit F [fab-corp.com]
This is what I use for a 1000' link (Score:5, Informative)
Here is the AP that provides access. [groovin.net]
Nothing special to do a 1000' link. Just a parabolic grid antenna on the client side.
Here [fab-corp.com] are some parabolic grid antennas.
Re:This is what I use for a 1000' link (Score:2)
WRT54G (Score:3, Informative)
Re:WRT54G (Score:2)
WDS, RIP or OSPF? The guy is talking about covering serveal acres, so default isn't going to cut it. And unless minitar's are less then 33 bucks (current price of WRT54G after rebate).....
Try waveguides (Score:2, Interesting)
Possible (Score:2, Informative)
Re:Possible (Score:2)
Surely if the cable runs are 1000' over fields between greenhouses, the only equipment needed to intercept would be a pair of snips and a crimper?
maximizing coverage with the right antennas (Score:5, Interesting)
cantennas work over long distances! (Score:2, Interesting)
The cheapest way, wireless repeaters every 100' (Score:3, Funny)
RFC 1149 (Score:5, Funny)
Re:RFC 1149 (Score:4, Funny)
Re:RFC 1149 (Score:2, Informative)
This is a greenhouse environment.
Its simple, really (Score:2, Informative)
24dbi external antenna (Score:2)
http://shopping.netsuite.com/s.nl/c.403468/sc.5/c a tegory.35/.f [netsuite.com]
Three levels of gain - 15, 19, and the highest being a very respectable 24dbi. That would probably be overkill for your use - just placing the 15dbi gain one up on each end and aiming them properly should give you an excellent signal point to point. They're fully weatherproof too, unlike the "pringles can" jobbies, and they're actually reasonably priced. The 24 is under $70 iirc and you don't have to buy a pigtail. (cantenna pigtails cos
I was the IS manager for a large greenhouse.... (Score:5, Informative)
If you are looking for a setup like what I had (points of presence in every greenhouse), all you need are some cheap(ish) base stations for the endpoints, and a kick ass 24dB omnidirectional antenna for the master base station at the head office. Build small networks at each pop and bango. If you want roaming in a few areas, throw in a small consumer wireless base stations and hook it up to the pop.
If, however, you are looking at using the network for business critical voice services or control and monitoring systems, then you had better look seriously at fiber (fiber ring preferably). You never know when some bird lays a massive shit on the antenna. Wireless is simply not as reliable as wired.
super-high-gain omnis don't work well... (Score:3, Informative)
From what I've heard, the best policy is to stick to lower-gain omnis for local base stations and use dishes for any long range links.
A RadioLabs and Linksys solution (Score:3, Informative)
http://www.radiolabs.com/products/wireless/wirele
Also, I agree with an earlier post suggesting the Linksys WRT54G or GS running the SveaSoft firmware.
http://www.sveasoft.com/ [sveasoft.com]
With a slightly better antenna and a few WRT54G's in a WDS configuration, you could easily provide both wireless and wired connections in the remote buildings and have some wireless coverage between the buildings as a bonus.
With enough of the WRT54G's in the WDS configuration and using OSPF, you could create a "self healing" component to the network.
G'Luck
I am thinking this would solve your problem... (Score:2)
Keep it simple (Score:2, Informative)
Regardless, my first approach is try what is simple. I presume its reasonably flat and obsticle free land. A simple, adequately tall mast (http://www.hyperlinktech.com/web/antenna_height. p hp) near the centre of his land with a high gain omnidirectional antenna should give pretty impressive
Just use a long distance 802.11b access point (Score:2, Informative)
What about power lines? (Score:2)
If money is no limit, run fiber-optic and bury it deep...
Don't bother with 802.11 (Score:2)
Also, wifi is short range - directional antennas are at best a partial solution, and aren't much easier in many cases than running cat5.
You never specified the actual problem you're trying to solve. You already have telephone wires going to the greenhouses, what is wrong with your existing setup? Speed? Connection problems?
Or is it just plain "Geek factor"
Sumatrabucks (Score:4, Funny)
A suggested setup (Score:2)
Nothing wrong with HomePNA, just add WiFi... (Score:2)
Actually that is what I do in my home. WiFi couldn't get everywhere so since I had some HomePNA cards around, I just created a HomePNA long distance link with a couple of WiFi nodes at the ends.
The old spider omni (Score:3, Informative)
Try this simple and trusted design of the good ol' spider omni http://flakey.info/antenna/omni/quarter/ [flakey.info]. Been using it a lot and will extend an AP's range to between 300 and 500 metres (that's around 900 to 1,200 feet).At the Bristol Wireless [bristolwireless.net] project we've used them on roof-tops to hop from point to point in a mesh network, I'd imagine it'd work just as well for greenhouses.
Linux Mesh (Score:2)
$180/node.
You can install SIP for VoIP if you want.
Smartbridges (Score:3, Informative)
the all in one units.
simple. cheap.
Re:Smartbridges (Score:2)
Various options (Score:2)
The bridges can be a variety of technologies depending on the needs and setup. Visible light / infrared / laser repeaters are pretty good for line of sight apps but have problems in extremely severe weather.
The cantennas are a good choice. From all accounts homemade can be as good as commercial easily, if you build them with precision. Just use wired to 802.11 bridges, set each bridge to a different channel. If you use wireless
200mW Access Points would help (Score:2, Informative)
http://estore.itmm.ca/ [estore.itmm.ca] has many models of 200mW access points.
I'm missing something... (Score:3, Insightful)
I also can't figure out why you'd have a 1000' foot gap between buildings... unless you're mostly doing nursery. If that's the case then all the chaps saying to go wired would probably re-think their stance. You don't want to bury wire in a field that's getting replanted with nursery on a regular basis. Of course, you've already got phone lines down there, so, like the title says: I'm missing something.
Something that I haven't seen addressed are the CONDITIONS that this equipment will have to operate and survive in. At best you're dealing with very humid. Depending on the setup you might also be dealing with very hot. When the stock is gone and its summer time a greenhouse gets HOT around here -- 110 degrees or so on some days. I think I've seen 120 once or twice while in there. Dust gets everywhere if you're using any sort of automated filling or soil mixing system which given your size I'd imagine you are. Although then again I go back to the "mostly nursery" idea and it changes.
For the non-greenhouse geeks in the house nursery (perennial plants) are typically grown in regular black-dirt top soil. The kind of dirt you'd find in your yard. Potted annual plants are grown in a mixture that largely consists of peat moss and that stuff flies FOREVER when its dry, which it is during mixing or filling of containers.
So.. 90% humidity, 75 degrees, dust flying everywhere... will a LinkSys WAP with an external antenae hold up to that? Don't ask me, I'm just a "farm boy"
I'm still VERY curious as to why you need/want more throughput then you already have. I'm not saying your crazy or anything, I'm just really wondering what I've missed in greenhouse technology. Seems to me if you're doing any sort of data collection with a roaming handheld you could just want until you cradled the device for a data download. I can't imagine anything that would need to be real time except for outside temp, a number of inside temp monitors, outside wind, sun conditions, etc.
Re:I'm missing something... (Score:2, Informative)
We want to be able to access via laptop current production request, orders, etc from anywhere on the site. Also we want to be able to control climate from any location on the property.
Other applications are webcams for us
CHEAPEST solution (Score:2)
Narrow Beam Width (Score:2)
I have two WiFi antennas. A homemade cantenna I built using these instructions. [turnpoint.net] I've experimented with adding a funnel [seattlewireless.net] with limited success.
I get pretty good distance with it (big improvement over standard Omni that came with my D-Link 802.11b card, but nothing like what I get using my parabolic grid antenna. [sharperconcepts.net] It's about $50 after shipping, but the 15 degree beam width is worth it over the 35-50 degree beam width you'll get out of a h
Sveasoft (Score:2, Interesting)
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
What kind of data? (Score:2)
For the former, you're on the righ track. For the latter, there are any number of potential solutions that can't be decided on without more information.
How about multi-hop? (Score:2, Informative)
No, dishes won't work - and here is why (Score:2)
Gain comes at a price.
The only way an antenna can produce gain, is, by limiting the directions in which it is effective.
A longer dipole (vertically mounted) becomes less effective in the vertical range - which means a long dipole that is perfectly vertical will not really transmit a lot of the energy upwards (and will therefore suck for satellite communication - which you don't
Re:(Relatively) old antennas are the way to go.. (Score:2)
Cellphone message/call detector pen (Score:2)
Re:Always remember: (Score:3, Insightful)
Re:Always remember--to think outside the box. (Score:3, Funny)
Sometimes the opposite is true.
With software in particular :)
Re:Don't be lazy (Score:3, Informative)
Re:No question defined, please restate (Score:2)
Re:No question defined, please restate (Score:2)
What's the actual budget? How much downtime is acceptable and what damage will be done when it does go down? How much traffic will the network carry, and is it bursty or steady? ETC.