A simple mom and pop store is looking into setting up WIFI for an RV park (back of facility) and customers on two sides that would access the wifi from outside the store. The wifi is to attract users to the store rather than to set up a business.
Here is my guestimate of what would be required, though I'm looking for good suggestions. Note that this should run without a PC present other than to set it up.
Take the dsl and feed it to a router such as di-804hv. [I've had good luck with both DLink and SMC gear, with DLink providing better support.] Now I have 4 ports For each side of the building,connect a high power wap like Senao NL-2611 CB3 Plus. I like the idea that they are powered over the ethernet since they means only one walwart in the system. On each outside wall, a flat pannel antenna such as
I'd like the user about 200ft away to access the system with a low power wifi card. I've done easily twice that distance using a 250mw card and a homemade biquad, so I am assuming the reciprocal would be true.
One last thing...Is there a way to prevent users on one side of the building from accessing their wap, going through the router, then hacking a user on a different wap connected to the router. That is other than the users making sure file sharing is turned off.
Maybe I should have mentioned "on the cheap" in the post. Also, that company is in Pa., and the site is in the west. I'm looking for hardware advice. If this is not the forum, perhaps someone can suggest a better one.
I know you are trying to be helpful, but really, you aren't. For one thing, I need to surround a building. Wifi probably won't shoot though industrial sized refrigerators. I'm quite sure I need outdoor antennas. Second, I need some range.
I've d> By a $39.00 linksys wirless router and hook it to a internet line. WRT54G >
Ok, so everything has to be inside the wireless router. No problem. Various version of the WRT54G replacement firmware have built in wireless hotspot software. I've been tinkering with DD-WRT which has Chilispot hotspot software inside:
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of the local wireless hotspots use EWRT.
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's also Sputnik firmware for the WRT54G.
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addition, there are some stand along products offered by DLink:
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(scroll down to hot spot gateways at bottom).
Lay off the high transmit power. You create an "alligator" which is a system with a big mouth and small ears. Your overpowered transmitter will be heard much farther than users can get into the system. The high power access points don't hear any better than the low power versions. The ideal is where the range in both directions is symmetrical.
Time for some math. Those are 13dBi antennas with a -3dB beamwidth of
35 degrees (see data sheet and pattern). That means, to cover a 180 degree wall (back of building), you'll need 5 of these. To cover a full 360 degrees, you'll need 10 of these antennas. Now, are you sure you really want such high gain?
Are you supplying the card? Are you supplying the card with an external or attached antenna? Are you supplying anything?
Is the user in a window or trying to shoot through the aluminium wall of the camper/trailer? They might have a chance at 200ft though the window, but forget it going through the wall of the camper/trailer. Think outside (rooftop) antenna.
Also, got any trees in the way? Every campground I've ever been in is literally overgrown with trees (for privacy). 2.4GHz doesn't like to go through trees or bushes.
Maybe. It really depends on the topography, location, folliage, and interference. Interference is critical and unfortunately unpredictable. If you did your 200ft test on the ground, you probably were not high enough to pickup much interference. However, put the same system at rooftop level, and you'll hear the world.
Yes. The WRT54G and many access points have a "client protection" feature. Linksys misnames is "AP protection" but they're the same. What happens is that all the clients can only direct traffic through the router and on to the internet. No client can connect to or see any other client. It's designed for exactly what you're thinking and will prevent client to client connections, attacks, file sharing, and local game networks.
Forgotta paragraph. What you want is called a sector antenna. These have fairly high gain, very narrow vertical radiation angles, and very wide horizontal radiation angles. See:
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example, a 120 degree (horizontal) sector antenna, with a gain of about 12dBi will have a vertical radiation pattern of about 14 degrees.
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's rather narrow and has to be carefully positions. However, it won't take 5 antennas to do the job and you won't be sending most of your RF into the sky and into the ground.
Now we're onto something. Taking a look at the layout, a 90 degree sector would work out best. This particular building has fuel pumps in the front with lanes on either side, so the wifi zone would need to be past the traffic zone. There is an above ground fuel tank that would set one limit. Users would stilll have to be in the 100ft to 200ft zone. The angle required is quite small, like 3 degrees so
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the setup is done as a loss-leader, I like the idea that the users will have to be parked in a certain area. This increases the guilt factor.
Let's ignore the RV park at the moment. This still leaves a few questions. How much gain is enough? Horizontal or vertical polarization? [I know the high gain omni directional antennas that some use will be vertically polarized, but I think the PCMCIA cards are horizonally polarized. I don't know the polarization of notebooks with built in antennas.]
My preference is still to get with a router and individual waps. The store has an absentee owner. I think a camera on one of the router ports so that the owner could observe his store would seal the deal.
BTW, unless Cisco has cleaned things up, I stay away from Linksys gear. In the past, the support was crap.
I have no idea. You didn't answer any of my questions about the type of radios that the clients will be using, whether they will be going through the trailer walls, whether there are any tress in the way, and some clue as to the topography. All these have a big effect on the path loss and therefore the required gain.
It doesn't matter. The typical PCMCIA is mostly horizontally polarized. However, the vertical component is rather substantial, and reflections are epidemic. The consensus is that horizontal picks up less junk and reflections, while works best for going between obstructions (i.e. trees and fences). The reason vertical is more popular is that a vertical omnidirectional antenna is a trivial design, which a horizontally polarized omnidirectional antenna is a design nightmare.
Say goodby to most of your broadband bandwidth unless you restrict the size and frequency of image uploads.
I had mentioned to ignore the trailer park situation. The users will be between 100ft to 200ft away with no obstructions. I can hardly predict what equipment the average wifi user will have. Figure on a cheap ass Fry's $9 Airlink card as the worse case.
About 8dBi gain should be enough for a typical +15dBi xmit power access point. So lets do some math:
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TX power = +15dBm TX coax loss = 3dB including connectors TX ant gain = +8dBi Distance = 0.038 miles (200ft) RX ant gain = 0dBi (cheap PCMCIA or MiniPCI card) RX coax loss = 0db RX sens = -84dBm (at 12Mbits/sec) Fade margin = unknown
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a fade margin of 28.2dB which is quite good. You could probably do with a 2dBi antenna (dipole or rubber ducky) but that would a bit risky. At 200ft, almost any antenna will work if you have line of sight.
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