Wireless Advice for Me?

Smoked2121 · 05-10-2008, 09:00 PM

I'm trying to see if I can hook up a wireless solution at my house, and am looking for advice with you guys. First, if I wanted to have the ability to hook up to free Wifi networks from my house with around a 4-10 mile radius with relatively good connection what equipment should I look for? A have a relatively unobstructed view from a 10ft high 'pole' on my roof on which I can connect a long-range antennae to. I can also easily reach it due to a low chimney. What adapter, antennae, and assorted cords would be best to get this project going? I am looking at the HD18035 24 dB gain antennae but am looking for you guys to show me the best adapter. Also the type of cord, i'm going to need about 30 feet of it. Thanks, if possible project under $250. Or around there. Post any suggestions please.

Bugbyte · 05-10-2008, 09:26 PM

WiFi isn't designed to go that far. Not only that, even if you can receive WiFi, the hotspot doesn't have the ability to transmit that far. Unless you control both ends of the connection, you are unlikely to be able to make this work reliably.

That said, you can extend the range of WiFi considerably by using something called a Yagi antenna. You can even build your own out of a Pringle's can. Lots of Google hits if you put in 'Yagi'.

BarryWoods · 05-11-2008, 02:18 PM

Even if you have a kick *** antenna on your end, unless they have one on theirs, you aren't going to get a connection. You are also going to be looking at around $300 minimum for hardware to get a good setup.

DarquePervert · 05-12-2008, 06:56 AM

Quote: Originally Posted by BarryWoods

Even if you have a kick *** antenna on your end, unless they have one on theirs, you aren't going to get a connection. You are also going to be looking at around $300 minimum for hardware to get a good setup.

I spent less than $90 (including shipping!) for a high-power USB wifi adapter and 7dbi antenna. With this setup I have picked up hotspots from as far as a half-mile away, if there is good line of sight and I'm not rolling. I know most (if not all) of these hotspots were using a standard-issue off-the-shelf wireless router by Linksys, Netgear, Belkin or some other popular make.

I don't know if qualifies as "good" by your standards or not. I have no complaints.

The problem with a directional "pringles can" antenenna (or "cantenna") is that it's directional. Sure, you get better range, but you have to point it in the general direction of the hotspot/access point.

Bugbyte · 05-12-2008, 07:51 AM

Yeah, 1/2 mile is probably the best you could hope for in an omni configuration. But he says he wants to pick up *other* people's hotspots. Those are probably located in non-optimum locations.

BarryWoods · 05-12-2008, 09:15 AM

My definition of "good" is faster than my iPhone's connection(slightly faster than dial up). Unless he lives somewhere with no trees, and is on top of a hill, there's no freaking way he's getting a connection at the distances he's wanting.

DarquePervert · 05-12-2008, 11:32 AM

Quote: Originally Posted by BarryWoods

My definition of "good" is faster than my iPhone's connection(slightly faster than dial up). Unless he lives somewhere with no trees, and is on top of a hill, there's no freaking way he's getting a connection at the distances he's wanting.

Oh, I 100% agree.
You're not going to get that sort of range for wifi without a high powered point-to-point setup, even if he's atop a hill with direct line-of-sight to the AP.

When you get into distances over a couple miles, you're talking about radio or microwave setups that are a bit much for a vehicle install. They require FCC registration and special licensing and the like.

blackcobra487 · 05-13-2008, 01:49 AM

There should be some other way to get long range wireless. I remember when my dad was driving an 18 Wheeler. He said he was talking to someone 9 miles away on a CB radio. What is it about WiFi that makes it so limited? I would guess it's because WiFi isn't intended for this kind of use. Maybe CarPCs will become popular enough that something better will become commercially available at an affordable price.

DarquePervert · 05-13-2008, 06:48 AM

It's simple.
Voice requires very low bandwidth.
Data requires a lot more bandwidth.

When you start dealing with broadband-type speeds (54mbps for 802.11g), the power that would be required to transmit/receive across HALF the distance of your dad's old CB radio would be enough to cook hot dogs.
Can it be done? Sure.
Can you or I afford it? No.

Understand that for a mobile internet connection, wifi is NOT the ideal setup for internet. You'd be bouncing from AP to AP as you enter/exit range of them and it would make your connection "jumpy" (for lack of a better term).
A far superior solution is cellular broadband (those PCMCIA cards that every cell company offers). Hopping from cell tower to cell tower is far more seamless than hopping from wifi access point to wifi access point.

Bugbyte · 05-13-2008, 08:32 AM

Quote: Originally Posted by blackcobra487

There should be some other way to get long range wireless. I remember when my dad was driving an 18 Wheeler. He said he was talking to someone 9 miles away on a CB radio. What is it about WiFi that makes it so limited? I would guess it's because WiFi isn't intended for this kind of use. Maybe CarPCs will become popular enough that something better will become commercially available at an affordable price.

The physics of the two radios are different.

Radio waves are a form of energy. That energy can be transmitted. An example of this is a microwave oven. My microwave transmits 1000 watts of energy into the food inside it. The energy from the waves causes the food to cook.

A WiFi transmitter is about 1 watt, much, much lower power. A CB radio is limited to a maximum of 4 watts output. Thus, it has 4X the power of a WiFi transmitter. AM radio stations can be as much as 50,000 watts.

Lower frequency radio waves travel farther than higher frequency waves. A CB radio transmits on AM while the WiFi is basically FM. CB's transmit in the 27 megahertz band -that's 27,000,000 cycles per second while WiFi is 2.4 gigahertz - that's 2,400,000,000 or an order of magnitude higher. Pretty close to the microwave band, which is why a microwave oven can interfere with your WiFi transmitter.

So, there are at least two things going against WiFi -short wavelengths at low power vs. CB which transmits long wavelengths at higher power.

Lastly, CB's transmit analog data while WiFi transmits digital data. A little interference listening to a CB transmission is no problem. A little interference on WiFi keeps the channel from working properly or slows it down substantially.

There is a new technology called WiMax that is more suitable to a several mile transmission range but it is not the same thing, will most likely be rolled out by telecom providers, and is not in widespread use yet.

BarryWoods · 05-13-2008, 12:34 PM

Quote: Originally Posted by Bugbyte

A WiFi transmitter is about 1 watt, much, much lower power. A CB radio is limited to a maximum of 4 watts output. Thus, it has 4X the power of a WiFi transmitter. AM radio stations can be as much as 50,000 watts.

That's with an amp right? Most radios are labeled in mW (milli-watt). Real good ones are in the 300 to 500 mW range. A standard linksys wrt54g is 63.1mW.

Bugbyte · 05-13-2008, 06:34 PM

Not sure. I just looked up WiFi max wattage and found that max was 1 watt.

BarryWoods · 05-13-2008, 09:22 PM

Quote: Originally Posted by Bugbyte

Not sure. I just looked up WiFi max wattage and found that max was 1 watt.

Well that really depends on where you are located. In the US the FCC says 1 watt for the radio and 4 watts EIRP (equivalent isotropically radiated power), if you're using an omni antenna. If a device is FCC regulated, it will be below this. The problem comes in when people start building their own setups. It's not too difficult to go over this with some of the stuff I've seen here on the board. Take the 1 watt amp, add a 6dbi omni to it, and you're at the max 4 watt output. You'll actually be just a tad under giving losses for connectors. You really should never use an amp on wifi unless it's absolutely necessary, and you know what you're doing. Even short term exposure from a one watt amp and a high gain directional antenna can damage your eyes, and other sensitive parts of your anatomy.