Cabletron Systems 9033073 manual Determining Range Clearance, Fresnel Zone

Page 41

Determining Range &

3

 

Clearance

 

The Fresnel Zone

As identified in Chapter 2 - Installation Guidelines, you need a clear line-of-sight to set up an outdoor antenna installation that meets your requirements in terms of range and throughput performance.

NOTE

A wireless outdoor antenna connection that lacks sufficient clearance will suffer from poor performance. When radio performance is poor, the network response is poor as well, due to many retransmission attempts of lost data frames.

In Chapter 2, we described the shape of the radio beam (Fresnel Zone) as being bulged in the middle. The exact shape and width of the Fresnel Zone is determined by the path length and frequency of the radio signal.

If any significant part of the Fresnel Zone is obstructed, a portion of radio energy is lost, resulting in reduced performance. For optimal performance, you must ensure that the antenna products you choose, in combination with the height of the antenna installation above ground, will provide sufficient clearance to allow your antenna installation to cover the distance between the two wireless sites.

Outdoor Antenna Installation Guide

3-1

Image 41
Contents RoamAbout 802.11 Outdoor Antenna Installation Guide Page RoamAbout 802.11 Outdoor Antenna Installation Guide Page Canada Regulatory InformationOutdoor Antenna Installation Guide Your email address Getting HelpPage Table of Contents Determining Range & Clearance RoamAbout 14-dBi Directional Antenna Page Who Should Use This Guide IntroductionAbout This Guide Installing the Antenna Installation GuidelinesOrganization of this Guide Introduction This ChapterAppendix D Calculating Range & Clearance Appendix C The Antenna Cabling SystemRoamAbout Outdoor Kit Introduction Configuration and Management Installing a RoamAbout Access PointHardware Specifications Finding Additional InformationOther Sources of Information Additional files on your diskettesPage Site Prerequisites Installation GuidelinesOverview of the Indoor Installation Pre-Installation ChecklistSelecting the Right RoamAbout PC Card Indoor Installation OverviewRoamAbout PC Card Identification Installation Guidelines Placement of the RoamAbout Access Point Installation Guidelines Antenna Cable Route Placement of the Lightning ProtectorInstallation Guidelines Antenna Mast/Wall Bracket not included in kit Overview of the Outdoor InstallationAntenna Placement Potential Obstacles for a Directional Antenna Tripod Mount Antenna Mast/Wall BracketAntenna Mast Requirements Wall Side MountRoamAbout Antennas Grounding SystemAntenna Polarization Antenna Alignment AP Manager Point-to-Point Diagnostics ScreenAntenna Cable Routing Before Climbing the Roof Page Fresnel Zone Determining Range ClearanceDetermining Range & Clearance Other Considerations Page Planning the Antenna Installation Installing the AntennaElectrical Hazard Warnings Safety PrecautionsElectrical Hazard Warnings Installation Overview Mounting on a Mast Mounting the AntennaMounting the Directional Antenna Prevent damage to the plastic antenna mounting base Mounting on a Flat Surface Mounting the 14-dBi Antenna to a Wall Mounting the Omni-directional AntennaMounting the Omni-Directional Antenna to a Mast Connecting the Antenna Cable Installing the Antenna Sealing the Cable Connectors General Description Contents of the Antenna BoxRoamAbout 14-dBi Directional Antenna RoamAbout 14-dBi Directional Antenna Table A-1 Specifications 14-dBi Directional AntennaRoamAbout 7-dBi Omni Directional Antenna RoamAbout 7-dBi Omni-Directional Antenna Outdoor Cabling Components Selecting the Correct Connector TypeAntenna Cabling System Antenna Cabling System Table C-1 Selecting the Correct N-Type ConnectorOutdoor Cabling Components Table C-2 Cable Assembly Specifications RoamAbout Cable AssemblyRoamAbout Lightning Protector Table C-3 Lightning Protector SpecificationsFigure C-1 Lightning Protector Installation InstallationRoutine Maintenance Low-Loss Antenna Cable Table C-4 Cable Specifications for the 6m 20 ft AntennaTable C-6 Cable Specifications for the 22m 75 ft Antenna Table C-5 Cable Specifications for the 15m 50 ft AntennaPage Introduction Calculating Range ClearanceDynamic Range Budget MBit/s Omni-Directional 7-dBi Table D-1 Dynamic Range FCCTable D-2 Dynamic Range ETSI. France & Japan Determine Line-of-Sight Clearance Link speed versus RangeDynamic Range Minimum Clearance Maximum Range Table D-3 Minimum Clearance for Maximum RangeCalculating Range & Clearance Determine Typical Range Table D-4 Actual Clearance and Typical Range Which Antenna do You Need