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eVLBI map

Experiment TEVLB8 was carried out on 15 Jan 2004 using the Onsala, Westerbork and Cambridge telescopes of the EVN. Data were streamed directly from the formatters at Onsala and Westerbork at a datarate of 128 Mbps to disk packs at JIVE without any disk buffering at the stations. Data from the Cambridge telescope were also recorded simultaneously on disk packs at Jodrell Bank and transferred to JIVE after the experiment.

The data from the three telescopes were correlated and processed off-line to produce a map of the target source, 2007+777 (a compact BL Lac object).

As part of the same experiment, data were also transferred directly from the formatter at Onsala to JIVE at a rate of 256Mbps. These data were correlated with data from the Cambridge telescope (transferred after the experiment) and fringes were successfully produced. See here for a fringe plot from a selected subband (the two colours represent the two polarizations).

Network details

The new link to Onsala (OSO) is a 1Gb/s line to Chalmers University of Technology, Gothenburg, purchased on OSO's behalf by SUNET from Skanova, a subsidiary of Telia. Chalmers in turn links to SUNET at 2.5 Gbit. This figure shows data flow on the OSO-Chalmers link on Thursday 15th Jan 2004.

Jodrell Bank (Cambridge) data are carried by a 150Mb/s line to the Manchester Computing Centre and via Network North-West to superJANET4 (UKERNA). 

UKERNA and SUNET (via NORDUnet) link to GÉANT and onward to SURFnet. At SARA in Amsterdam data are routed to the Gb/s lines to Dwingeloo.

Westerbork data are currently carried to Dwingeloo on the production link which is shared with other traffic between the two sites. Competing traffic on this line may account for the data losses. A dedicated line for VLBI will be available shortly.

Network details diagram.