Basically today's WiFi accessing range is limited to a few hundred kilometers. It is accessible only within the organization or a little extended surrounding to the organization. It is depend upon the strength of the signals.
The much the signal is strong the larger area it will cover. In some places around the city access points are made. In this case one can access the data not from the original source point but form the installed access points. The range of the
WiFi access depends upon kind of the antenna used. In the case of unidirectional antenna one cannot access from the opposite direction of the antenna. To access data from surrounding the access points the multidirectional camera should be used.
Access Point
The range of the signal will depend on several factors, including power output of your wireless card or router;
receive strength of the wireless card or cards you are transmitting to, obstructions buildings or trees which may be in the way of your transmitting path, walls, etc.
Ranges
Since there are so many factors which can determine the overall range of your
wireless system. A rule of thumb however is to always choose an antenna which you think may be overkill. Why? Because the power output is extremely small it is necessary to have as much gain as possible.
Most wireless cards have a power output of 32 milliwatts (+15dBm), which is roughly the same amount of power it takes to light a high power
LED (Light Emitting Diode). LEDs are bright, but imaging trying to see one at a large distance or through a building or trees. This is why the antenna is critical for amplifying that signal so it is as strong as possible.
Range varies in a WiFi network depending on the type of WiFi radio you have, whether or not you use special antennas, and whether your network is in an open environment or in a building with lots of walls and furniture. The composition of your walls and floors can also have a major impact. WiFi is a very low powered radio signal and does not penetrate metal, water or other dense materials.
The WiFi Alliance does not measure or compare different products and their range. However, it has found that a WiFi network generally provides a range of about 75 to 150 feet in a typical home or office. In an open environment like an empty warehouse or outdoors, a WiFi network may provide a range of up to 1,000 feet or more. With the right antennas and optimal placement, a range of up to a mile is possible.
With effort of some
VoIP service proivders, today it is possible to connect the
VoIP router into the existing central phone box. And we can connect every phone at home and office with
VoIP. Though, this service is banned in some countries, yest most countris have legalized it. Major
VoIP service providers are rushng their VoIP services to the countries where the VoIP has been legalized.
With WiFi technology (802.11b or 802.11a), a "gradual degradation" in range occurs. This means that, instead of stopping all together, your data transmission rate just becomes slower as you move farther away from the access point. For example, with WiFi 802.11b technology, within 100 feet of the access point, the WiFi radio in your laptop computer will get about 11 Mbps data rate. As you move farther away, that rate will drop down to 5.5 Mbps, then to 2 Mbps and finally to 1 Mbps. Considering that many DSL and cable
