Normal Range

• The normal range of a residential wireless modem (a modem with a built-in wireless router) is 150 feet, according to purveyors of wireless equipment like Time Warner Cable. That's more than enough reach to connect every point in most houses. In corporate or public settings, more robust wireless networks can usually reach up to about 300 feet, although they will usually be extended with multiple access points and repeaters. A better way to look at it is that you're likely never more than 300 feet from the nearest antenna.
  
  

Restrictions on Range

• Numerous conditions can reduce your wireless modem or router's useful range by absorbing the signals or by interfering with them. Faraday cages will absorb wireless signals. Any metal enclosure is a Faraday cage, so you may find it hard to access the Internet in an elevator and in certain buildings. As for interference, any other electronic devices operating in the same frequency range as the wireless signal, often 2.4 GHz, can disrupt it. Microwaves are a common source of trouble, as are some cordless phones and baby monitor radios.
  
  

Range Extenders

• Microsoft has a number of recommendations for boosting the range and quality of your home wireless signal. In the case of some wireless modems and routers, you can replace the omnidirectional antenna with a high-gain antenna that transmits in a single direction with much greater power. You can purchase wireless repeaters to connect areas far away from the modem where the signal strength is low. Repeaters take in the signal and amplify it, then send it out again. Simpler recommendations include lifting your modem off the floor, situating it away from metal objects and walls, and changing your wireless source's channel to one with less interference.
  
  

Wireless Wide Area Networks

• If you are connecting to the Internet through a wireless wide area network, you can get a signal from much farther away, enabling continuous Internet access while you are on the go. This helps to link remote areas to the Internet without laying expensive cable, and is also a boon to commuters. WiMAX networks have a range of up to 30 miles. Most 3G cellular networks have a range of about 10 miles. 4G networks vary but are generally better than 3G networks, although as of 2011 3G networks are more mature and thus have a greater reach in terms of towers available.