Installation
2 Installation
2.1
Installing the antenna
2.1.1 Overview
This section explains how to select and install your antenna.
You must select antennas for WL-TX-900 modules to avoid contravening the
maximum power output limit on the unlicensed channel. The net gain of the
antenna/cable configuration should be no more than 0 dB in Australia / New
Zealand.
ATTENTION
The net gain of an antenna/cable configuration is the gain of the antenna (in dBi) less
the loss in the coaxial cable (in dB).
For example, an SG900-6 antenna with a CC20/900 cable has a net gain of 2dB (i.e.
+8 dB – 6 dB) at 900 MHz.
The WL-RX-900 module has no limitation on antenna gain, as this module does not
incorporate a radio transmitter.
The following table details the gains of some typical antennas:
Antenna
Gain (dBi)
Dipole with integral 3m cable
0
Dipole without cable
2
5dBi Collinear (3dBd)
5
8dBi Collinear (6dBd)
8
3 element Yagi
5
6 element Yagi
10
The following table details losses for typical cables:
Cable
Loss (dB per 10m) at 900 MHz
RG58 -5
RG213 -2.5
Cellfoil -3
14