scope:

The present document specifies technical characteristics and methods of measurements for S-band meteorological radar systems intended for the surveillance and classification of hydrometeors with the following characteristics:

• Operating in the following frequency range: - 2 700 MHz to 2 900 MHz.

• Utilizing unmodulated pulses or phase/frequency modulated pulses also known as pulse compression.

• The maximum output power (PEP) does not exceed 1 MW (i.e. 90 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 2 077 MHz to 14 500 MHz. The lower limit of this frequency range is obtained as the cut-off frequency of the generally used WR284/WG10 waveguide according to IEC 60153-2 [i.2]. The upper limit corresponds to the upper limit stated in ERC/Recommendation 74-01, Table 1 [1]. The highest operating frequency of 2 900 MHz has been used to calculate the upper limit.

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 2 700 MHz to 2 900 MHz. According to provision 5.423 of the ITU Radio Regulations [4], ground-based radars used for meteorological purposes in the band 2 700 MHz to 2 900 MHz are authorized to operate on a basis of equality with stations of the aeronautical radio navigation service.

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.