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Troposcatter Radio Links : Telecommunications Library - G. Roda

Troposcatter Radio Links

Telecommunications Library

By: G. Roda

Hardcover Published: 19th December 1988
ISBN: 9780890062937
Number Of Pages: 368

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Prefacep. xi
An Introduction to Tropospheric Scatter Radio linksp. 1
Beyond-the-horizon and tropospheric scatter pathsp. 2
Short historical outline of beyond-the-horizon radio communicationsp. 5
The place of troposcatter links among other transhorizon communications techniquesp. 7
Main characteristics of troposcatter radio linksp. 8
Design calculations and their reliabilityp. 10
Feasibility of a troposcatter pathp. 11
Specific field of application of troposcatter systemsp. 14
Types of troposcatter systemsp. 14
Advantages of troposcatter systemsp. 17
International recommendations and authoritiesp. 18
Comments and suggestions for further readingp. 20
Referencesp. 20
Review of Statistical Distributions used in Troposcatterp. 21
Random variables and their statistical distributionsp. 21
Normal and log-normal distributionsp. 23
Normal distributionp. 24
Log-normal distributionp. 26
Rayleigh distributionp. 27
Nakagami distributionsp. 31
Nakagami m distributionp. 31
Nakagami n distributionp. 32
Composed distributions--convolutionsp. 35
General remarksp. 35
Convolution of normal distributionsp. 36
Convolution of log-normal distributionsp. 36
Convolution of Rayleigh distributionsp. 36
Convolution of log-normal and Rayleigh distributionsp. 37
Correlation between random variables--autocorrelationp. 37
Comments and further readingp. 38
Referencesp. 39
The Geometry of the Troposcatter Path and Related Problemsp. 41
Profile of the troposcatter pathp. 42
Definition of geometrical data and parametersp. 44
Basic datap. 44
Angular parametersp. 46
Length parametersp. 47
Geometrical parameters of antennasp. 48
Derivation of the formulaep. 48
Calculation of the effective radius of the Earthp. 48
Calculation of the distance and elevation of the horizon over sea (or flat land)p. 49
Calculation of the elevation angle of the horizonp. 50
Calculation of angles [alpha] and [beta]p. 50
Calculation of the angular length and the scatter anglep. 50
Calculation of the distance along the horizon rays to their crosspointp. 50
Calculation of EH = hp. 51
Calculation of EG = h[subscript 0]p. 51
Calculation of path differencesp. 52
Commentsp. 53
The Tropospheric Scatter Mode of Propagationp. 55
Tropospheric refractivity and its characteristicsp. 56
The refractive index and its gradientp. 56
The effective radius of the Earthp. 57
Structure of the atmospheric refractivityp. 62
Radiometeorological parametersp. 65
Troposcatter multipath transmissionp. 66
Representations of the main propagation phenomenap. 68
Degradation of antenna gainp. 69
The troposcatter multipath signalp. 72
Spread and bandwidth parameters of the mediump. 73
Variability in the level of the tropscatter signalp. 75
Anomalous propagationp. 79
The CCIR climatesp. 79
Comments and suggestions for further readingp. 81
Referencesp. 81
Diversity Techniquesp. 83
Decorrelated paths and diversity effectsp. 83
Diversity systemsp. 85
Space diversityp. 87
Frequency diversityp. 87
Polarization diversityp. 88
Angle diversityp. 88
Time diversityp. 90
Linear combination of diversity branchesp. 90
Predetection or postdetection combinationp. 91
Combining methodsp. 93
Signal selectionp. 94
Equal-gain combinationp. 96
Maximal-ratio combinationp. 96
Combined signal and diversity gainp. 98
Implicit diversity techniques to combat multipath distortionp. 100
Combiners and adaptive modemsp. 103
A simple baseband combinerp. 103
An i.f. combinerp. 106
Multiple-subband moden for digital transmissionp. 107
Independent sideband diversity modem for digital transmissionp. 107
Distortion adaptive modem for megabit transmissionp. 108
Comments and suggestions for further readingp. 111
Referencesp. 111
Path Loss and Path Distortionp. 113
Path loss between isotropic antennasp. 114
Method of calculationp. 116
Path geometry calculationsp. 117
CCIR methods of calculating path lossp. 117
Method Ip. 121
Method IIp. 125
Radiometeorological methodp. 132
Chinese methodp. 132
Calculation of instantaneous path loss with fast fading and diversityp. 133
Dependence of path loss on the main parameters and its actual variabilityp. 140
Path loss for line-of-sight linksp. 141
Diffraction path lossp. 142
Knife-edge diffractionp. 143
Smooth-earth diffractionp. 145
Path loss in particular propagation conditionsp. 146
Evaluation of path distortion and the multipath delay spectrump. 148
Comments and suggestions for further readingp. 153
Referencesp. 153
Tropospheric Scatter Equipmentp. 155
Composition of a troposcatter terminalp. 155
Transmitting systemp. 158
Transmitters (exciters)p. 158
Power amplifiersp. 160
Receiving systemp. 163
Receiversp. 163
Input thermal noisep. 165
Design parameters for analog radio equipmentp. 167
Analog receiver threshold for telephonyp. 168
Telegraph failure point (telegraphic threshold)p. 169
Thermal signal-to-noise ratio in a telephone channelp. 169
Overall performance characteristics of analog radio equipmentp. 171
Design parameters of digital radio equipmentp. 176
Bit error rate curve of a digital systemp. 177
Threshold of a digital receiverp. 179
Overall performance characteristics of digital radio equipmentp. 181
Typical troposcatter radio equipmentp. 182
Analog radio equipmentp. 183
Digital radio equipmentp. 184
Radio frequency filters and duplexers--isolatorsp. 186
Coaxial and waveguide feedersp. 187
Antennasp. 188
General characteristics of fixed antennasp. 188
Mobile antennasp. 191
Gain and gain degradation: path gainp. 191
Multiplex equipmentp. 193
Analog multiplexp. 193
Digital multiplexp. 195
Auxiliary equipmentp. 195
Ability of combined equipment to overcome path lossp. 196
Systems with adaptive capabilityp. 197
Comments and suggestions for further readingp. 200
Referencesp. 201
Path Design and Prediction of Performance for Analog Troposcatter Linksp. 203
Performance objectivesp. 203
Noisep. 205
Thermal noisep. 206
Intermodulation noisep. 212
Path calculationp. 221
Conventional troposcatter linksp. 222
High quality troposcatter linksp. 225
Telegraphic transmission performancep. 228
Comments and suggestions for further readingp. 231
Referencesp. 232
Path Design and Prediction of Performance for Digital Troposcatter Radio Linksp. 233
Digital transmission on a troposcatter channelp. 233
Signal-to-noise ratio in telephone channelsp. 234
Transmission degradation: digital errorsp. 234
Multipath delay spread and pulse distortionp. 235
Expedients against multipath delay dispersionp. 236
Behaviour of diversity receptionp. 238
Quality of digital transmissionp. 242
Outages and quality parametersp. 244
Hypothetical reference circuitp. 245
Performance objectivesp. 245
Design of a digital troposcatter linkp. 248
Path calculationp. 248
Path equationp. 249
High quality troposcatter linksp. 250
Conventional troposcatter linksp. 250
Comments and suggestions for further readingp. 252
Referencesp. 253
Topographic and Survey Problemsp. 255
Preliminary work using mapsp. 256
Calculation of the antenna azimuthp. 256
Drawing the connection line on the mapsp. 259
Plotting the horizon skyline profilep. 260
Surveying problems on sitep. 263
Basic principlesp. 264
Fundamental parameters of geographical astronomyp. 267
Coordinate systemsp. 269
Determination of the direction of the distant stationp. 270
Determination of the horizon skylinep. 271
Determination of latitude and longitudep. 272
Topographic problems in antenna installation and line-upp. 274
Orienting the antenna in the horizontal planep. 275
Orienting the antenna in the vertical planep. 276
Assessment of the profiles of large billboard antennasp. 277
Comments and suggestions for further readingp. 280
Referencesp. 280
From Planning to Implementation and Maintenancep. 281
Planning the systemp. 282
Site surveysp. 284
Siting the stationsp. 288
Choice of frequency bandp. 291
Frequency planp. 293
Procedure for design calculationsp. 295
Choice of equipmentp. 296
Radio equipmentp. 296
Multiplex equipmentp. 298
Antennasp. 298
Power equipmentp. 300
Air conditioningp. 301
Installation of the systemp. 301
Fixed systemsp. 302
Installation of transportable systemsp. 311
Deployment of mobile systemsp. 311
Tests and measurementsp. 314
Path propagation testsp. 314
Tests on the installed systemp. 316
Radiation hazardsp. 321
System operationp. 322
Maintenance problemsp. 323
Cost considerationsp. 324
Comments and suggestions for further readingp. 326
Referencesp. 327
CCIR Recommendations and Reports Concerning Transhorizon Systemsp. 329
Computer Calculationsp. 333
Bibliographyp. 335
Indexp. 343
Table of Contents provided by Syndetics. All Rights Reserved.

ISBN: 9780890062937
ISBN-10: 0890062935
Series: Telecommunications Library
Audience: Professional
Format: Hardcover
Language: English
Number Of Pages: 368
Published: 19th December 1988
Publisher: Artech House Publishers
Country of Publication: US
Dimensions (cm): 22.9 x 15.2  x 2.3
Weight (kg): 0.72