Reference Manual

1. Overview
LUM0020CD Rev June-2020 Page 10 of 112 Copyright © 2019FreeWave
This document is subject to change without notice. This document is the property of FreeWave Technologies, Inc.
and contains proprietary information owned by FreeWave. This document cannot be reproduced in whole or in
part by any means without written permission from FreeWave Technologies, Inc.
Warning! Do not connect the LRS455A-C, LRS455A-CE, LRS455-T series radios to
DC power without terminating the antenna port to a suitable load, such as a 50 ohm
antenna, or an attenuator with a power rating greater than or equal to 2 W.
Powering up without a load attached will damage the radio and void the warranty.
1.1. Choosing a Location for the Radios
Placement of the FreeWave radio is likely to have a significant impact on its performance. The key
to the overall robustness of the radio link is the height of the antenna. In general, FreeWave units
with a higher antenna placement will have a better communication link. In practice, the radio
should be placed away from computers, telephones, answering machines, and other similar
equipment. The cable included with the radio usually provides ample distance for placement away
from other equipment. FreeWave offers directional and Omni-directional antennas with cable
lengths ranging from 3 to 200 feet. When using an external antenna, placement of that antenna is
critical to a solid data link. Other antennas in close proximity are a potential source of interference.
Use the Radio Statistics to help identify potential problems.
The Show Radio Statistics page is found in option 4 in the main Setup menu or in the Diagnostic
information in Tool Suite. An adjustment as little as 2 feet in antenna placement can resolve some
noise problems. In extreme cases, such as when interference is due to a Pager or Cellular
Telephone tower, the band pass filters that FreeWave offers may reduce this out-of-bandnoise.
1.2. Choosing Point-to-Point or Point-to-MultiPoint Operation
Note: In an LRS455A-C, LRS455A-CE, LRS455-T radio network, you can use only one Repeater.
A Point-to-Point network is best suited when your network consists of one Master and one Slave
radio.
Important!: Adding a Repeater to a network reduces the throughput by 50%. For
e
xample, o
ver-the-
a
i
r throughput in a network running at 2-Level GFSK and with the Repeaters parameter disabled is
9600 bps. With the Repeaters parameter enabled, the over-the-air throughput drops to 4800 bps.
The LRS455A-C, LRS455A-CE, LRS455-T radios are narrowband radios and have a limited
channel size based on the license obtained from the regulating body. Therefore, the radios can
experience a dramatic impact in throughput if a Repeater is implemented in the network.
If large amounts of data are transferred and a Repeater is added to the network, the polling host /
RTU settings must be optimized to accommodate for the lower throughput. Polling host / RTU
optimization settings include reducing block / packet sizes and increasing overall time-out
parameters.
In a Point-to-MultiPoint network (also referred to as MultiPoint network), the Master radio is able
to simultaneously communicate with numerous Slave radios. In its simplest form, a MultiPoint
network functions with the Master broadcasting its messages to all Slaves. If requested by the
Master, the Slaves respond to the Master when given data by the device connected to the data
port. This response depends on your setup. You can extend the reach of a licensed network with
LRS455A-C, LRS455A-CE, LRS455-T
User-Reference Manual
••