Chapter3 Installation
3
3. Installation
3.0
Overview
The pMDDL2450 complies with FCC part 15 at the modular level for
operation in the license-free 2400-2483.5 MHz ISM band. This chapter
provides guidelines for installing and deploying equipment which
incorporates the pMDDL2450 module.
3.1
Estimating the Gain Margin
Successful communication between pMDDL2450 modules is dependent on
three main factors:
System Gain
Path Loss
Interference
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 pMDDL2450 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 pMDDL2450
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 dB
Cable Loss = 2 dB
Antenna Gain = 6 dB
Antenna Gain = 3 dB
