Affiliations: Dipartimento di Elettronica e Informazione, Politecnico di Milano, Piazza L. Da Vinci 32, 20133 Milano, Italy Tel.: +39 02 2399 3659; Fax: +39 02 2399 3413; E‐mail: [email protected] | Centro Studi per le Telecomunicazioni Spaziali, CNR, Politecnico di Milano, Piazza L. Da Vinci 32, 20133 Milano, Italy Tel.: +39 02 2399 3454; Fax: +39 02 2399 3413; E‐mail: [email protected]
Abstract: The ITALSAT propagation experiment started in early 1991 and ended in January 2001. A receiving station for the radio‐wave propagation experiment at 18.7, 39.6 and 49.5 GHz was installed in 1992 at Spino d'Adda (45.4 N, 9.5 E), near Milano, Northern Italy. In addition to the beacon receiver, which records every second the attenuation measured at the 3 frequencies along a slant path of 37.8° elevation angle, the earth station was equipped with a tipping bucket rain‐gauge and meteorological instruments recording temperature, humidity and pressure. This paper presents 8 years (1993–2000) of copolar attenuation statistics. The cumulative distribution functions (c.d.f.) of attenuation due to rain for 1993 and total attenuation (gas, clouds, turbulence and rain effects) for the period 1994–2000 are presented along with the rain intensity c.d.f. for the period 1992–2000. The total attenuation c.d.f., averaged over 7 years, is compared with predictions obtained using ITU‐R Rec. P.618‐7 as for gas, clouds and scintillation contributions and ITU‐R Rec. P.618‐7 and EXCELL model for rain contribution. The measured long‐term cumulative distribution of rain intensity, averaged over the period 1992–2000, is used as input for rain attenuation models. The ratio between standard deviation and mean value of total attenuation calculated at various time percentages for the 7 years is used to characterize the year‐to‐year variability. C.d.f. of total attenuation conditioned to the season and the hour of the day are also calculated.