Sharing wifi between buildings

Its possible to do with the proper antenna. However, you would need significant power to drive the extra gain (at least 20db). Those are difficult to find and expensive to build. The DTV dish may server in this capacity if you found the proper power and the specialized Equipment to 'extend the 802.11g signal ( 11.g would be recomended). Oh and you would probably need clear line of sight with no obstructions of any kind.
Just an example. At DefCOn and Black hat this year in Las Vegas, the WIFI challenge winner transferred data using an 11.g carrier signal over 50miles. That took some major equipment.

Not in my experience. Perhaps 20 is overkill but 5 in most cases won't maintain a connection at any significant distance, I suppose it somewhat depends what he means by "block". A rural blocks vary a lot. City blocks he is talking a greater distance.

20 db is more than a bit overkill. Well can't speak to your experience but I've put up several hundred links of what would amount to a city block. Hell a couple of city blocks with 4 dBi patch antennas. Not even a very tight beamdwidth. Get a yagi with a 30 degree beamwidth and and at least 5 dB, you could go 7 if you want some confidence. Not a problem.

This is a (small) city and the blocks (at least in this neighborhood) are 50 meters long per side and the streets are 10 meters (and up) wide.

What is a yagi? its like a frequency modulator?

Should i just hookup the antenna to a wifi router with coaxial port or I'm missing some other equipment?

Ph33r my....3r...w41t...

Haha i cant believe it! a pringles can?
Damn,is too cool and weird at the same time . I knew you could built something like that, but working as good as a dish or a normal antenna? its just amazing...

BTW i bet a steel bowl would do the job better than that, plus you get no corrosion and aesthetic issues

Ph33r my....3r...w41t...<P ID="edit"><FONT SIZE=-1><EM>Edited by JRX on 02/11/05 09:09 AM.</EM></FONT></P>

Good point, there's cylinder-like bowls too, but seeing the classing dish layout of the normal bowl makes me thing it could work.

I`ll post my experiences in the future.

Ph33r my....3r...w41t...

ok, I have no problem conceeding to your expertise on this. My experience, which is basically doing war driving experiments sponsored by a gvt lab to see if folks were complying with WEP/WPC policy, is certainly not as credible for this thread. The antenna used in my situation was built by some antenna geeks who may have had a secret pact to max out db. I made an erroneous assumption that because that antenna was ~22db and that we were monitoring from various distances between 100 and 500 meters that what I quoted was credible.
I am not an expert on this by any means, but I am learning.
Thanks

PS: it seems that a yagi may not be necessary to accomplish what he wants to do.<P ID="edit"><FONT SIZE=-1><EM>Edited by palmerg on 02/11/05 01:09 PM.</EM></FONT></P>

I just think that for the cost versus the performance some of these Cantennas we're seeing (granted they weren't competing against commercially manufactured units) were very nice and would certainly be more economical, not to mention fun - it seems the original poster is up to the challenge too.

<P ID="edit"><FONT SIZE=-1><EM>Edited by palmerg on 02/11/05 04:05 PM.</EM></FONT></P>

2 Qs. 1- did you have to do much focusing between the two loactions or just sort of point it in the general direction?
2- What is the general orinetation of the Wire element inside the can? The article seems to say that most work best if it is almost straight up and dowm or almost at right angles to the ground.
This is really interesting. I am definately building one and the reasons you do it is a good one for me as well since I have been known to get a call from a neighbor about fixing their computer too.
Also, how can you beat the price? Assuming I do a competent build job.

<P ID="edit"><FONT SIZE=-1><EM>Edited by palmerg on 02/11/05 09:54 PM.</EM></FONT></P>

You know, this low budget antennas make possible to build a private network between houses blocks away one of each other to share data and other resources. It only takes some common APs and the cantennas to interconnect a whole campus or a medium neighborhood.

Back to the topic, do you really thing that the can is the best thing available? My only real concern is corrosion (and having to replace it too often) what about a stainless tube? or a steel cylinder?

PD:back to the dish, cant it be modified the same way as the cans?

Ph33r my....3r...w41t...

Stainless cans are pretty weird, basically becos most people trash the cans (ergo, they aren't intended for a long-last use)

I could use a aluminium pipe (in fact, i think the signal will be better with that) instead of the can.

I just mentioned the dish becos i have a spare one (the other is in use) and the better the signal quality is...

BTW, searching for a good can i found a weird lettuce dryer in my parents kitchen. It resembles one of those mechanical satellite antennas from the 80s. The best part is that is already has a hole right in the middle for the wire (one thing less to do) and its pretty small (laptop sized dish XD). Just one thing: its full of little holes. Not that the entire structure is made of holes, but its has 1 for every 3 and a half MMs.

Does that affect the signal?

Ph33r my....3r...w41t...

I tend to agree. Read the whole Cantenna website, including all the links. Its very technical and describes the working of a waveguide antenna pretty fully. Variation is encouraged but within the constraints of a specifc formula. There is a link that explains the use of the Direct TV antenna to basically mage the directional waveguide antenna into a spread spectrum device. Can't mix and match the two, it seems to me.

I know it is adjustable, I'm just not sure if it can get into a shape that would work. You would have to look up those crazy formulas to see if it would work. I can't remember off hand where they are but I'm sure google can tell you fairly quickly

<A HREF="http://www.folken.net/myrig.htm" target="_new">My precious...</A>

The formula in the link I posted way earlier will only apply to the waveguide type of antenna. Diameter of the open end of the can is the discriminator and sets up the frequency range and the overall length of the waveguide needed and th eplacement of the 1/4 wavelenght wire which connects to the pigtail. Those antennas are designed to be more directional while dish antenna, although needing to be focused, will radiate a much wider swath.
So:
1- If you want focused directional and if your veggie dryer opens up over a wide spectrum of diameters it really only helps if you can also adjust or modify the lenght of the "barrel" relative to that diameter so to speak.
2- If you want a spread spectrum coverage to broadcast WiFi in a wide area then the veggie dryer may work but you really can't use the technology or techniques specifically mentioned in the Cantenna posts. There you can use the Cantenna/Direct TV setup that is mentioned in a link on the Cantenna page (I sent that out as a seperate URL).

Of course experimentation is valuable and fun but certain laws governing antenna design do guide the process. Hey who knows you may write a new law that includes veggie dryers.

I would think a dish would be good for recieving. Why would they have Dtv if it didn't? lol

<A HREF="http://www.folken.net/myrig.htm" target="_new">My precious...</A>