User's Manual
Table Of Contents
- Part A – Preface
- Safety Information
- Revision History
- Important Information
- Compliance Information
- Part B – Feature Overview
- Introduction
- Features and Benefits
- Q Data Radio Range
- Part C – System Topologies & Operating Modes
- System Topologies
- Operating Modes
- Part D – Feature Detail
- Hardware
- Efficiency and Bandwidth
- Connectivity
- Ease of Use
- Security
- Part E – Radio Planning and Design
- Radio Path analysis
- BER & Fade Margin
- Radio Accessories
- RF Feeders and Protection
- Part F – Quick Reference Guide
- Introduction
- Half Duplex Radio - QR450
- Full Duplex Radio - QB450
- Hot Standby Half Duplex Radio - QP450
- Hot Standby Full Duplex Radio - QH450
- LED indicators
- Connecting Antennas
- Communication Ports
- Activating Transmitter
- Factory Default
- Digital I/O
- Connecting to Web User Interface (WUI)
- Resolving Ethernet Connection Issues
- Part G– Quick Start Guide
- Step-by-Step Point to Point Setup
- Step-by-Step eDiags Setup
- System Topology Configuration
- Serial and MODBUS
- Single Frequency (Simplex) Mode
- E-Series Emulation Mode
- Part H – Advanced
- Connectivity
- Ease of Use
- Security
- Part I – Installation & Commissioning
- Optimising the Antenna for Rx Signal
- Commissioning
- Part J – Firmware Updating and Maintenance
- Firmware Updating
- Global Firmware Updating
- Fuse Replacement - QR450
- Part K – Open Source License Acknowledgements
- Part L – Support Options
45
Document Number: 0100SM1401 Issue: 05-15
RF Feeders and Protection
Lightning Arrestor
A lightning arrestor is used to help minimise lightning damage to radio devices. Lightning arrestors are made to bleed off
electrostatic build-up to help prevent a direct lightning strike from hitting the antenna system. Also, if a lightning strike
happens nearby, the arrestor helps to route the energy to ground.
The lightning arrestor is typically installed on the inside of a radio hut, between a coaxial tail lead the antenna feeder cable.
The lightning arrestor comes with an N-Type female socket on each end.
RF Coaxial Cable
There are many types of RF coaxial cables available, but it is sometimes difficult to
know which type of cable to use.
There are two main aspects of a cable to consider when selecting the right cable for
the job.
Bend Radius:
The bend radius of a cable is a specification given to a cable to define how flexible
the cable is. Exceeding the bend radius specification can change characteristics
within the cable and lead to reduced RF performance. The thicker the cable is, the
wider its bend radius will be, however, the thicker the cable, the lower its electrical
resistance will be, providing less impact on the radio system gain.
The cable connected from the radio to the lightning arrestor is typically quite short. This allows a thin, flexible cable to be
used. Thin flexible cables have a higher electrical resistance characteristic than thick rigid cables, but as there is only a short
length being used, the impact on radio system gain is negligible. The thick rigid cable is typically connected from the hut to
the top of an antenna mast connected to an antenna.
Cable Loss:
Each cable has its own specified cable loss characteristics. These characteristics can vary depending on what frequency is
being carried through the cable. See the table below for typical cable loss values.
Loss (dB) Relative to Distance (m) - at 450MHz
Cable Type 1 dB 3 dB 6 dB 9 dB
RG58 2.3 m (7ft 6in) 7 m (23ft) 14 m (46ft) 20 m (65ft 6in)
RG223 3.1 m (10ft) 8 m (26ft) 18 m (59ft) 28 m (92ft)
RG213 6.1 m (20ft) 18 m (59ft) 37 m (121ft 6in) 55 m (180ft 6in)
LDF 4-50 19 m (62ft) 57 m (187ft) 114 m (374ft) 171 m (561f)
LDF 5-50 38 m (124ft) 114 m (374ft) 229 m (751ft) 343 m (1125ft)
Part E – Radio Planning and Design