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Documenting the Work

The site survey report describes the details that were completed as part of the survey and what might need to be done in the installation and configuration processes. When documenting the actual work, include specific details about the following in the report:

Analysis of the RF spectrum at the site

AP location and mounting methods

Antenna type and mounting methods

AP configuration for RF (when applicable)

Coverage map for each AP

Including detailed descriptions about these items in a final report will ensure that the details necessary for a properly installed and easy-to-maintain WLAN are available.

Detail about the location, the type of mounting, the antennas used, and the recommended cabling methods enhance the chances for an error-free, easy install. Here you can use photographs to great effect (with little text required). Use photos whenever possible.

When describing access point (AP) locations, the site survey engineer should be as specific as possible. It is recommended to use objects and identifiers to explain exactly where the AP is to be located. Use a photo to identify this in the report, and label the photos so that they correspond to the site map (see Figure 13-1).

If the AP is to be located in an aisle or hallway, specify which aisle or hallway, and where it is located in the facility. If possible, use some type of marking method (flagging tape or marker flags, for example) to identify the exact location. This provides the installer with a defined location and eliminates any question as to exactly where it goes.

Do not use as markers objects that might be temporary. If the object has moved before the installer arrives, the installer might not be able to find the location and might mount the equipment improperly.

Even more important than the AP location, the engineer must specify with as much exactitude as possible where the antenna is to be located. See the photograph in Figure 13-2.

Just stating "place the antenna on the wall above the doorway" is not enough. The installer might not be aware of RF characteristics and might place it behind the exit sign, so it is out of sight, thinking that this would look better. "Place the antenna on the wall above the doorway, a foot left of exit sign" is a better explanation. You can also use a picture to spell out exactly what the description means (see Figure 13-2). Notice the duct tape used to temporarily mount the antenna for the site survey. The AP and battery pack are placed above the ceiling on the wall edge.

A detailed description of how the antenna is to be oriented must be included. Whereas correctly positioning an antenna might seem simple to some who have a basic understanding of RF and antennas, many others just do not have such an understanding of proper positioning. In some cases, the installer might have no knowledge of RF (or even networking for that matter). In one case, a university installed APs with 2.2-dBi dipoles that both swiveled and had a flexible 90-degree coupler. The installer assumed the energy from the antenna was radiated out the end of the antenna, as with an LED pointer. Therefore, he placed the antennas in a horizontal mode, as shown in Figure 13-3, so that the energy was "radiated out both ends." The end result was great performance on the floors above and below, but poor performance on that floor itself.

If the antenna is omnidirectional, the engineer might mention that the antenna is to be mounted vertically, with the cable or connector at the top or bottom. If the antenna is directional, describe the direction in which the antenna should be oriented. A patch antenna might be described as "facing north" or "directed at the nursing station at the end of the hall," but unless the installer has an understanding of that particular antenna, it might not be installed properly. Again, a good photo can provide tremendous assistance here. The more directional the antenna, the more important this description.

Another entry in a survey report should be parameters and settings of an AP that can affect coverage. It is important to identify the parameters that were used in the survey, including transmitter power levels (of both the client and AP), data rates, channels, packet size, and thresholds. All of these parameters can affect the overall survey results, and may or may not be the same throughout a facility. If there is both a warehouse and an office environment in the same site, the warehouse might only need support for a few users, over a very wide area, with minimal bandwidth. For the warehouse, therefore, maximum power and minimum data rates would be used. In the office area, however, there may be a need to keep the data rate set to 11 Mbps, and the transmit power to some lower value to stay within the user density defined in the design.

The report should also detail the coverage of each AP and define that coverage at desired data rates in an included diagram. Electronic diagrams can be generated easily and make any report look more professional. Microsoft Visio is available with templates that include items such as APs.

The report should also indicate areas where WLAN coverage is not needed. This helps to prevent misunderstandings or the customer complaining later that there is no coverage in an area he believes was missed, even though the original design did not include coverage for that area. Without documenting no-coverage areas, you cannot prove that the survey was done properly and that the original design did not include these areas for coverage.

The report should detail the specifications for providing power to the APs. It is not uncommon for the survey engineer to discuss the proposed cabling runs with the site maintenance team (power and networking), including where and how they will attach to each system. A list of the system components, the network media type, and the network cabling methods recommended for connecting should also be documented.