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Radio Frequency Site Surveys

AirLink Automation has been certified by Cisco Systems as a provider of wireless site surveys

RF Site Survey Overview

Since radio signal coverage patterns are unique to each site where equipment is to be installed, an RF Site Survey is highly recommended as a means to determine the following:

· The areas within a site where users will need wireless LAN access

· The number and placement of access points within the site that will provide the desired areas of coverage

· The types and mounting locations of the antennas to be used with the access points

· All necessary mounting hardware, enclosures, cabling and power requirements, etc. that will need to be in place to support the access point / antenna installations.

· The existence and potential for radio signal interference from other wireless systems or RF enabled devices

· Wireless data rates for the planned cells, with considerations made for load balancing, redundancy and client connection speeds

AirLink Automation’s Step-By-Step RF Survey Process

Step 1: Site Drawings

Prior to visiting a site and starting the actual survey, we usually try to obtain a site drawing that will give us an idea of the layout of the site to be surveyed. Although blueprints are OK, we actually prefer to us copies of site drawings. Block diagrams developed via PC drawing software that show the approximate locations of structures within the site are usually sufficient as long as these drawings include all pertinent rooms, hallways, elevators, racking, open areas and or large machinery locations. For our purposes, we do not need exact scale representations of the site.

In most cases, we’ll consult the site drawings as we perform the survey. If they are copies and not originals, we will draw in coverage areas and add notes to the drawings that will give us some reference as to data rates, interferences, etc. We also usually transfer our field drawings to a second “clean” copy of the drawings and include these with our final survey report.

For sites where drawings are not available, we’ll develop the drawings ourselves using Word or Powerpoint.

Step 2: Visual Inspection

With site drawings in hand, we’ll then walk the facility with a representative of site. Using the drawing as a reference, we’ll start in the key areas (high numbers of users) and work our way around the site, checking the drawing for accuracy and asking questions about specific locations that we encounter. We’ll weather a certain area needs coverage and we’ll ask questions with regard to the location of LAN connectivity, i.e. data drops, wiring closets, etc.

Step 3: RF Survey

Once we know what needs to be covered and at which priority, we then bring in our access points, battery packs, antennas, cables and mounts and actually begin surveying the site. We’ll use a client radio installed on a PC, or the actual RF devices to be use in the site to “ping” radio packets off access points that we will temporarily install around the site. Note that LAN connectivity will not be required during the RF survey.

As we walk the site we’ll pay close attention to the readings shown by our survey utility. The utility will tell us if we are in or out of coverage range with our survey access point and will tell us if we are in a fast, medium or slow area of the coverage cell. Interference issues are also monitored by the utility during the survey.

Step 4: Documentation

With consideration for the installation of the system, we document our survey findings in as high a level of detail as possible. In many cases, we may be performing the installation a few months after the survey, so good documentation is essential to streamlining the installation process.

In addition to using copies of the site drawings to show coverage areas, we also mark and number the locations of the access points and their antennas with tape. These reference points are then noted on the diagram and will include notes covering such things as the installation hardware required, the routing of any necessary cabling, the need for power etc.

Once the survey is completed a survey document package is provided to the end user. This package will include coverage maps, access point mount location descriptions, and proposed cable runs for connecting each AP’s Ethernet cabling back to the existing LAN. The survey document will also show a listing of all the parts, cables and mounts that will be required in order to perform the installation.

Sample Parts List:

Item	Description	Part Number	Quantity
Access Point 1	Cisco 350 access point 2.2 dBi whip antenna Mounting kit with plate	AIR-AP352E2R-A-K9 AIR-ANT3351 AIR-ACC1833	1 2 1
Access Point 2	Cisco 350 access point 2.2 dBi whip antenna	AIR-AP352E2R-A-K9 AIR-ANT3351	1 2
Access Point 3	Cisco 350 access point 2.2 dBi whip antenna Mounting kit with plate	AIR-AP352E2R-A-K9 AIR-ANT3351 AIR-ACC1833	1 2 1
Access Point 4	Cisco 350 access point 8.5 dBi patch antenna Articulating antenna mount	AIR-AP352E2R-A-k9 AIR-ANT3549 AIR-ACC2662	1 1 1