Site survey and installation recommendations

The roles

This guide looks at two roles in a network installation. The planner and the Installer. Both have essential roles in a successfull wireless LAN installation. Here are the task divisions:

Planner

• Link budgets
• Site surveys
• Proximate placement of AP/antennas
• HMS cautions

Installer

• Exact placement of AP and antennas
• Cabling and Connector termination
• Antenna adjustments, testing
• Equipment knowledge
• Ex Certification and requirements
• HMS cautions

Technical recommendations

Through 12+ years of experience in designing wireless networks, we share some essential advice:

• Choose the shortest cable length possible (place APs in field if possible)
• Place antennas visible from several angles (corners etc)
• Generally place antennas in the upper part of walls (10 cm clearance to ceiling)
• Leave two wavelenghts (24 cm) between wall and antenna
• Don’t hide the antenna behind obstacles
• Don’t place the antenna horizontally
• Angle the antenna slightly downward when placed above ceiling height (check pattern)
• Use a site survey tool to determine coverage. (Netstumbler etc)
• Check for Wi-Fi channel interference (using Netstumbler etc)
• We recommend max 30 meters antenna cable for the standard configuration and maximum 50 meters cable for the amplified configuration
• Use state of the art APs and Antennas to get the best coverage

HMS cautions

There are some very important considerations when it comes to HMS and Explosion protection.

• Secure workplace. Some sectorial antennas are heavy and can cause damage when accidentally dropped
• Follow Ex instructions, check labels and certificates
• Follow Ex maintenance instructions
• Consider Lightning protection of antennas where applicable
• Power supply is 220 V AC

Link budgets and signal calculation

There are several online tools for calculating signal budgets. These are very useful for getting an indication of what link quality you will achieve. Number of antennas, material, type of coverage, number of clients, wall material etc needs to be accounted for in the design process.

Equipment and software

Doing an actual survey or test is the only way of knowing for sure how much coverage you will get. You can take two approaches to site surveys:

Commercial approach

Ekahau has an excellent site survey software that provides a complete solution for performing network planning. There are many other alternatives available

Budget approach

To perform a site survey on a budget you really need only a laptop, a battery driven AP and a free software tool like Netstumbler