Before going wireless, better plan on a site survey

Computerworld - BOSTON -- When conducting a site survey to set up a wireless LAN, users should follow a seven-step process, according to James T. Geier, principal of Wireless Nets Ltd. in Yellow Springs, Ohio.
Geier, who spoke yesterday about setting up WLANs at a preconference workshop at the 802.11 Planet conference here, urged companies to fully explore the location for the WLAN in an effort to avoid what could be time-consuming and costly problems down the road.
The following are some of the suggestions he offered:

• Get good drawings of the facility where the WLAN will be set up.


• Identify all user areas.


• Visually inspect the area.


• Test the facility and surrounding areas for radio-frequency interference.


• Determine the preliminary WLAN access point locations.


• Verify those access point locations by testing them.


• Document all of the findings.

Geier said it is important not only to study the drawings and the plans for the building or facility in which the WLAN will be set up, but also to make sure those plans are accurate. Old plans may not always reflect changes that have been made to buildings over time.
Getting the building manager involved can be a crucial part of the preliminary process because, in addition to finding out about changes to the building, the manager might be able to offer clues as to what the walls are made of, for instance, and other potential interference factors, Geier said. Reinforced concrete walls, for example, would stop radio waves, whereas plasterboard wouldn't be such an interfering factor.
Even crowds of people can cause problems. Geier noted that while he was conducting tests at Miami International Airport, he discovered that large crowds hurt WLAN performance.
It's also important to diagram where users will be working before taking a preliminary walk through the building. A walk-through isn't only to confirm the building plans, but also to find things such as wall sockets. Knowing where the wall sockets are will save time when the actual access point survey takes place, Geier said, because the power sources will already be known.
Following that walk-through, the entire area should be swept for radio-frequency interference, and if the company has a frequency manager, he should be involved. Radio-frequency interference can come from a number of areas, including WLANs at other companies, microwave ovens, cordless phones, elevators and nearby radio stations.
If the planned WLAN conflicts with another company's wireless network, the two companies will need to work out a compromise, something that's better to do before a WLAN is in place.
After these tests are done, preliminary