User's Manual

4 N2420B Operating Manual: Chapter 3 Installation

3. Installation

3.0 Overview

Qualified and experienced personnel must carry out the

installation, removal or maintenance of all antenna components.

The N802.11A-30 complies with FCC part 15 at the modular level for

operation in the license-free 5725 - 5875 MHz ISM band. This chapter

provides guidelines for installing and deploying equipment which

incorporates the N802.11A-30 module.

When used specifically in Point to Point systems excludes the

use of point-to-multipoint systems, omnidirectional applications,

and multiple co-located intentional radiators transmitting the same

information the power may exceed 36dBm EIRP as per FCC and

IC grant. The operator of the spread spectrum intentional radiator

or, if the equipment is professionally installed, the installer is

responsible for ensuring that the system is used exclusively for

fixed, point-to-point operations.

3.1 Estimating the Gain Margin

Successful communication between N802.11A-30 modules is dependent on

three main factors 1) System Gain, 2)Path Los, 3Interference.

System gain is a calculation in dB describing the performance to be

expected between a transmitter-receiver pair. The number can be calculated

based on knowledge of the equipment being deployed. The following four

factors make up a system gain calculation:

1. Transmitter power (user selectable)

2. Transmitter gain (transmitting antenna gain minus cabling loss between

the transmitting antenna and the N802.11A-30 module)

3. Receiver gain (Receiving antenna gain minus cabling loss between the

receiving antenna and the module)

4. Receiver sensitivity (Specified as -108dBm on the N802.11A-30

module)

In the following illustration, the transmitting antenna has a gain of 6 dB,

and the receiving antenna has a gain of 3 dB. The cable loss between the

module and the antenna is 2 dB on both the transmitting and receiving side.

Transmitter

30 dBm

Output Power

Receiver

Sensitivity =

-105 dBm

Cable Loss = 2 dBCable Loss = 2 dB

Antenna Gain = 6 dB

Antenna Gain = 3 dB