introduction to site surveys matt larsen, ceo skybeam
TRANSCRIPT
Introduction to Site Surveys
Matt Larsen, CEO
Skybeam
Goals
• Determining service availability for customers
• Finding potential interference sources
• Planning wireless deployments
• Gathering competitive intelligence
Hardware Needed
• Laptop
• 802.11 Compatible wireless card (Lucent, Prism or Cisco)
• Surveying Software (Netstumbler, Kismet, TT Site Survey Utility)
• Antennas (small omni, panel antenna)
Optional Hardware
• Symbol Tablet or Spectrum Analyzer
• Amplifier
• 900mhz/5.8 Converters
• Specialized Antennas (Yagi, Panel, Mobile)
• Mapping Software (Radiomobile, TopoUSA, MapPoint)
• GPS (with serial cable)
Optional Hardware (continued)
• Binoculars (for spotting antennas)
• Different Types of CPE Equipment for each type of situation
Customer Service Availability
• On site check to see if the customer can get a quality level of service. Can be done with just a laptop, card and antenna.
• Preferably, should use the same equipment that the customer will be using.
• Bring each type of CPE to pick out the unit for the customer’s situation
Customer Service Availability
• Obtain signal strength readings from the CPE and from the Access Point
• Simple ping test to the gateway
• Big packet ping (ping 192.168.1.1 –n 100 –l 1472)
• FTP Download
• FTP Upload
Customer Service Availability
• Should have acceptable signal strength• Simple ping test should be 100 percent• Big packet ping should be >95 percent• FTP download should be max available• FTP upload should not stall or be
exceptionally slow• If these aren’t met, there may be future
problems at the customer’s location
Customer Service Availability
• Record the results of your surveys
• Add GPS coordinates to help build your coverage profile
• Information from all site surveys, even failed ones, may be useful for future use and might save a few trips to customer locations
Knowing Your Spectrum
• Utilize commonly available hardware and software to get information about other RF users in the unlicensed spectrum areas
War Driving
• War Driving – Going through an area to determine where access points are and to obtain information about them
• Many software tools are available to collect and catalog war driving information
• How it works – Wireless card goes into RFMon mode (promiscuous) and sees all 802.11 packets that come across
War Driving Software
• Netstumbler (Windows)
• Kismet (Linux)
• Airsnort
• Wellenreiter (Linux)
Netstumbler
• Windows based
• Easy to use
• Works best with Lucent cards
• Interfaces with GPS to collect mapping information
• Signal Strength Graphs for each AP
• Doesn’t find hidden or <nossid> radios
Kismet
• Linux based• Works with Lucent, Prism and Cisco cards• Interfaces with GPS and Ethereal for dump
analysis• Finds hidden beacons and <no ssids>• Finds IP subnet of the traffic on each AP• Difficult to get running• Can also be run as a service on a Linux box to
continuously collect information
Spectrum Analyzers
• Real Spectrum Analyzers are expensive, but will provide very complete information about the spectrum
• Some inexpensive tools can provide useful information
• Teletronics Site Survey Tool
• Symbol Tablet FH Analyzer
Teletronics Site Survey
• Windows Based
• Requires a Teletronics Radio Card
• AP Browser is limited
• Shows signal levels on all different channels
• Useful for making a preliminary evaluation of the best channel to use
Symbol Site Survey Tablet
• DOS Based and self-contained
• Best used with an external antenna
• Good for identifying different types of radios (FHSS, DSSS, Wmux, etc)
• Can be combined with a 5.8 converter to look at the 5.8Ghz range
Tips and Tricks
• Use these tools at your AP locations to help pinpoint interference sources and plan your deployments
• Keep a record of Access Points that you find and update it regularly
• Use omni antennas for discovery of other Aps. Then use directional antennas to pinpoint the location of the other antennas
• Look for the weaknesses in your network – because someone else is!
Conclusion
• The tools and techniques discussed here should give you a good idea of what is out there, how to deal with it and how to plan your deployments to provide a quality level of service. War Driving our own systems is a good way to coordinate your frequency use with any other WISPs in your area
Contact Information
Matt Larsen
Skybeam
PO Box 2231
Scottsbluff, NE 69363
www.skybeam.com