Do you have a site that is just out of reach of your physical network?

Maybe a remote warehouse across a field, or maybe two building that are separated by a public street?  Getting right-of-way permits and hiring a professional boring company to come in and push underground pipe may be too time consuming and costly.

Consider installing a wireless point to point network. 

Considerations:

• No special FCC Radio licensing required if using standard 802.11 spec devices. 
• Devices must stay below 1 Watt of Radio Power to remain within the rules.

Requirements:

• You need Electrical Power at both ends
• You need line of site (a direct path between antenna locations) between each end that is unimpeded by electrical lines, trees, buildings, traffic, water towers, etc.
• Less than a mile without involving a professional wireless engineer.

Types of Point to Point Antennas:

• Yagi – Directional Antenna that is just the size of large paper-towel roll.
             Example:  WIFI-LINK
• Mesh Dish – Larger profile, but connects much further than Yagi.  Requires more sturdy physical mount than yagi.  Has some movement in wind.
             Example: WIFI-LINK
• Solid Dish – Requires strong mount pole and strong mounting accessories.  Use for long distances with maximum radio effectiveness.
             Example: CISCO

Sample Parts List using a Mesh Dish Antenna.

Note: I included spare wireless access points, since these guys get hit by lightning on occasion.  Also, if you want good isolation, installing ethernet to fiber transceivers at the entry to your building, you will have optical isolation (preventing lighting from entering the building) across your fiber lines.

Sources: 

802.11 Limitations

CISCO

EIRP Calculator

TESSCO

WIFI-LINK.COM