scope:

The present document specifies technical characteristics and methods of measurements for X-band meteorological radar systems intended for the surveillance and classification of hydrometeors with the following characteristics: • Operating in the following frequency range: - 9 300 MHz to 9 500 MHz • Utilizing unmodulated pulses or phase/frequency modulated pulses also known as pulse compression. • The maximum output power (PEP) is not greater than 250 kW (i.e. 84 dBm). • The transceiver antenna connection and its feeding RF line are using a hollow metallic rectangular or elliptic waveguide. • The antenna is rotating and can be changed in elevation. • The antenna feed is waveguide based and the antenna is passive. • The orientation of the transmitted field from the antenna can be vertical or horizontal orientated or it can be both simultaneously. • At the transceiver output a RF circulator is used. NOTE 1: Since transceiver and antenna are based on hollow metallic rectangular waveguide the frequency range for measurements that needs to be addressed covers 6 556 MHz to 26 GHz. The lower limit of this frequency range is obtained as the cut-off frequency of the generally used WR90/WG16 waveguide according to IEC 60153-2 [i.2]. The upper limit corresponds to the upper limit stated in ERC/Recommendation 74-01 [1], Table 1. NOTE 2: Since at the transceiver output a RF circulator is used, it is assumed that the transceiver characteristics remain independent from the antenna. NOTE 3: Meteorological radar systems covered by the present document are expected to use the band 9 300 MHz to 9 500 MHz. According to provision 5.475B of the ITU Radio Regulations [4], ground-based radars used for meteorological purposes in the band 9 300 MHz to 9 500 MHz have priority over other radiolocation uses. NOTE 4: Further technical and operational characteristics of meteorological radar systems can be found in Recommendation ITU-R M.1849-1 [i.3]. NOTE 5: The relationship between the present document and essential requirements of article 3.2 of Directive 2014/53/EU [i.1] is given in Annex A.