After the successful VLBI experiment in 1995 at 86GHz and 215GHz between one antenna of the IRAM Plateau de Bure interferometer (PdB, France) and the IRAM 30-m telescope (PV, Spain) (Greve et al. 1995, Krichbaum et al. 1997), the decision was taken to equip PdB as a permament station for global VLBI observations, using the six 15-m diameter antennas as a combined phased array at 3mm (100GHz) or 1.3mm (230GHz) wavelength. In July 2002 it became possible to bring by helicopter the necessary equipment for VLBI observations to Bure i.e. the maser, the tape recorder, the formatter and decoder, and the VLBI FS9 control computer.
Tests took place on October 8th and 9th,2002 at 86-89GHz (3.5mm) on the 685 km long baseline between the 6-element phased array of the PdB Interferometer (France) and the 100-m telescope at Effelsberg telescope (EFF; MPIfR, Germany). The length of the baseline between PdB and EFF is 685km, in the direction North-South. Unfortunately, the IRAM 30-m telescope was not available because of continuously poor weather conditions. Even so, a S/N ratio of several hundred with an angular resolution of about 0.9 milli-arcsec was achieved.
Thereafter the 6-element Plateau de Bure phased array participated in late October 2002 in the last CMVA coordinated global 3mm VLBI observing campaign. The IRAM 30-m did also participate, this time under excellent weather conditions. A first fringe plot between the two IRAM instruments is shown in Fig. 1. The intention is to use PdB from now on as a regular VLBI telescope.