k&k engineering
Planning handbooks
Planning and engineering
of radio-relay networks
The handbook describes
methods to plan, survey and engineer radio-relay hops. The various calculation
principles and formulas that determine the hop geometry, the antenna heights,
ground reflections etc are discussed, as well as the most common procedures
for survey and the associated equipment. In detail, the following subjects
are discussed:
Basic planning
- Network configurations
- System configurations
- Frequency bands
- Path lengths, terrain
aspects and site selection
- Equipment selection:
radio-relay equipment, passive repeaters, antennas, waveguides, power supply,
towers and masts, buildings, containers, shelters
- Economic
considerations
Survey and site determination
- Map survey
- Determination of
sites
- Co-ordinates and
bearing
- Calculating with
co-ordinates
- Path profiles
- Field survey
- Site survey
- Path survey
- Global positioning
system (GPS)
- Survey equipment
- Check list for a
radio-relay project
Engineering
- Free-space basic
attenuation
- Planning criteria
for path clearance
- Determination of
antenna heights
- Check of path clearance
- Path attenuation
and receiver input level
- Attenuation due to
atmospheric gases
- Influence of obstacles
and partial clearance of the 1st Fresnel zone on path attenuation
- Antenna and transmission
line parameters
- Passive repeaters
and their influence on the total path attenuation
- Plane reflectors
- Antennas back-to-back
- Ground reflection,
its calculation and countermeasures
Performance and availability
as applied to radio-relay systems
The handbook discusses the
wave propagation and equipment parameters that determine the performance
of a radio-relay path. The ITU planning objectives are explained. The
formulas and methods to predict both performance and unavailability are
described., both for the radio hop and for the radio circuit (or link). A
great number of examples make it easier to understand the formulas. In detail,
the following subjects are discussed:
Planning
objectives for digital radio-relay systems
- Performance
and unavailability
- The concept of unavailability
- Unavailability planning
objectives
- Error performance
parameter definition
- Performance planning
objectives
Performance prediction
- Fading and propagation
models
- The equipment’s performance
characteristic
- Characteristic with
respect to fading
- The equipment’s sensitivity
to distortions due to propagation effects (selective fading)
- Performance calculation
- The multipath occurrence
factor
- Performance prediction
considering multipath fading and related mechanisms
- Fading margin
- Prediction procedure
for a hop going via a passive repeater
- Performance prediction
considering distortions due to propagation effects (selective fading)
- Performance and unavailability
prediction considering precipitation
- Attenuation caused
by rain
- Fading probability
for one hop due to rain
- Worst-month concept
and average annual probability
- Improvement of the
performance by diversity reception
- Diversity types
- Diversity improvement
- Total performance
- Diversity improvement
and hardware availability
- Other techniques for
alleviating the effects of tropospheric multipath fading
Unavailability calculations
- Unavailability and
reliability of hardware
- Single (unprotected)
structures
- Duplicated (protected)
structures
- Examples for protected
radio-relay equipment
- Line protection and
diversity
- Unavailability due
to precipitation
- Total unavailability
(The application
of the formulas for the calculation of the geoclimatic factor and the rain
attenuation assumes the access to 4 ITU-R data files. These files can be
downloaded from this homepage.)
Performance and availability
– a formula collection
This handbook contains all
formulas, described and discussed in the three other handbooks. It is
intended as a reference book for quick looking-up of formulas.
This handbook is also included
in the manual for RLTool and Formula planning tools.
(The application of the formulas for the calculation
of the geoclimatic factor and the rain attenuation assumes the access to
4 ITU-R data files. These files can be downloaded from this homepage.)
Frequency planning of radio-relay
networks
The frequency planning of
radio-relay networks is probably the most important issue in planning radio
networks. It is furthermore an international issue, as radio waves propagate
beyond any political border. This handbook discusses the various aspects
related to frequency planning. The formulas necessary to predict the interference
signal levels at the input of a disturbed receiver are shown and discussed.
Measures to counteract interferences or to decrease their signal level are
described.
All ITU recommended frequency
and r.f. channel plans are listed in the handbook’s appendix.
The influence of interfering
signals
- The mechanism
of interference
- The influence on the
wanted signal
Frequency bands
Setting up the frequency
plan
- Radio-frequency
channel arrangements
- International frequency
plans
- Application of passive
repeaters
The allocation of radio
frequencies
Interference calculation
- General formula
- Antenna gain and discrimination
- Formulae for triangular
network configuration
- Interference via passive
repeater
- Adjacent-channel attenuation
- Total interference
- Counter measures
Appendix
- ITU-R recommended
frequency plans
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Planning and engineering
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