M. Robson et al., OBSERVATIONS OF ATMOSPHERIC NOISE FLUCTUATIONS WITH A METER BASE-LINEINTERFEROMETER IN THE 13-17 GHZ BAND, Astronomy and astrophysics, 286(3), 1994, pp. 1028-1032
This paper describes the atmospheric noise fluctuations that we have o
bserved with the Cosmic Anisotropy Telescope (CAT) at Cambridge. The C
AT is a short baseline radio interferometer designed to make observati
ons of primordial anisotropies in the Cosmic Microwave Background Radi
ation at angular scales between 20 arcminutes and 1 degree. During cle
ar weather the observations are limited by receiver noise, whereas emi
ssion and scattering from clouds limits the sensitivity of the instrum
ent during rain and cloudy weather on the very shortest baselines. Flu
ctuations in the correlated antenna temperature up to 100 mK have been
seen, with a typical coherence time of 10 seconds.