ALMA-J Site Testing
ALMA-J Site Testing Archive
Last update 2005-06-07

11 GHz Radio Seeing Monitor

    Two sets of radio interferometers fabricated at Nobeyama Radio Observatory have been operating to monitor the radio seeing at 11.2 GHz. They are almost identical to those used at Nobeyama Radio Observatory. Each of these interferometers has 300 m baseline (east-west) and utilizes 11.2 GHz beacon from one of the Intelsat geosynchromous satellites as a radio source. A small set of interferometer, which is a preceder of the current system, was installed at Paranal (2400 m a.s.l.) in 1994 July. In 1995 July, the first set of the 11.2 GHz interferometer was installed at Rio Frio (4100 m a.s.l.). The second one has been operating at Pampa la Bola (4800 m a.s.l.) since 1996 July. As we decided Pampa la Bola-Chajnantor area as the first priority candidate of the LMSA site, the first interferometer was re-installed at Pampa la Bola in 1999 March. These two sets of interferometers are now operated in series to provide information on atmospheric structure up to 600 m.

Technical Description

    Figure 1: Block diagram