Long Range Wi Fi Antennas
Broadband wi fi networking is an aspect of radio that I find quite fascinating. With the right equipment, a low power signal can not only travel far but also provide excellent broadband connectivity. Antenna projects shown in on this site offer advantages to anyone seeking better performance of their 802.11 wireless network.
Any of the wi fi antenna projects shown here will provide longer range, lower required power for any data rate, and increased privacy (lower sidelobe radiation). If your network must penetrate concrete walls, runs from one building to another, or covers a large outdoor area, is to use a high gain wi fi antenna at both ends: access points and clients must both support their ends of the communications link.
For very long range, use a short helical, yagi, or biquad antenna mounted at the focus of a parabolic reflector. Wi Fi dish antennas offer the highest possible gain and longest connection range.
High Power Wi Fi is also an option for maximum range. Equipment is more expensive and more delicate than run-of-the-mill wireless devices, but a solid 30 dbm signal will penetrate walls in a building or connect at very long distances. A good match is a high powered wi fi adapter on the computer paired with a high powered access point (all with good antennas).
Bear in mind that beyond a distance of 3 km, throughput may begin to decrease due to the ACK timeout setting of the access point. ACK timing must be optimized for longer distances - especially over links covering dozens of kilometers.
Some articles to read that will raise your expectations of wifi performance:
- Rethinking Wifi for the Developing World
- Long Distance 802.11b Links: Performance Measurements and Experience
- Tuning Access Points for Long-Distance Applications
- A 279km experimental link in South America
- How a 125 mile unamplified wifi connection was achieved.
- Security issues pertinent to high performace wi-fi operation.
- Building a Rural Wireless Mesh Network.
- Quantifying wireless mesh network capacity.
Also, note that large antennas are not always the best for providing connectivity to a large and/or remote area. Wi-Fi mesh networking and mobile telephone ad hoc mesh networking can enable people to connect peer-to-peer without reliance on much infrastructure. Here is where users make the network, and it can function well in times of civil unrest or natural disaster.