Rec. ITU-R SA.1165-1 … TECHNICAL CHARACTERISTICS AND PERFORMANCE CRITERIA FOR RADIOSONDE SYSTEMS IN THE METEOROLOGICAL AIDS .
ANNEX 1
1 Introduction
    1.1 Daily meteorological operations
    1.2 Monitoring climate change
    1.3 Defence use
    1.4 Other users
2 Characteristics of radiosonde operation
3 Radio-frequency spectrum used in WMO operations
    3.1 Results from WMO survey
    3.2 Radio-frequency spectrum occupied in Europe
    3.3 Radio-frequency spectrum occupied in the United States of America
4 Operational requirements
5 Future trends
    5.1 Very strong upper winds
    5.2 Manpower efficiency resulting from highly automated systems
    5.3 Low radiosonde cost
    5.4 Independence from international NAVAID systems
    5.5 Possible improvements to spectrum occupation from improved radiosondes
6 Radiocommunication characteristics of current radiosonde systems
    6.1 Transmitter characteristics
    6.2 Ranging signal
    6.3 Receiving antennas