Message 1/505 Walter Alef Oct 17, 2000 05:29:03 pm +0200 Date: Tue, 17 Oct 2000 17:29:03 +0200 Organization: Max-Planck-Institute for Radioastronomy X-Accept-Language: en To: evntech exploder Subject: EVNtech: Bonn correlator report Sender: owner-evntech@jb.man.ac.uk Precedence: bulk ======================================================================= Status of MPIfR Bonn Correlator Centre ====================================== Version OCT 16, 2000 W.Alef & R.Porcas MKIV Correlator --------------- Following installation in December 1999 and an extensive period of test and development, the MPIfR MKIV correlator is now in use for both astronomy and geodesy experiments. Proper production correlation started after the implementation of phase-cal extraction in April 2000. A backlog of about 1.5 months exists for both geodetic and astronomical observations. The correlation efficiency for 1-pass correlation is still worse than that of the old MK III correlator. Exporting geodetic data to CALC/SOLVE is standard. A simple (not sufficient) interface to the Caltech software exists. Although many correlation modes remain to be developed or tested, the present tested capabilities include: => First fringes in MK3-Mode C (4-channel subset) - 15 DEC 1999 => Increase of the useable number of playback drives from 4 to 6. => First fringes with a VLBA mode (64-16-1) from a VLBA formatter (test experiment Eb-Mc, Feb 2000) - 16 FEB 2000 => Playback of a fan-out 1:2 mode - 15 MAR 2000 => Correlation of dissimilar tape speeds - 5 APR 2000 => Extraction of phase-cal signal - 6 APR 2000 => Replay of 2-bit sampling mode - 7 APR 2000 => Playback of a fan-out 1:4 mode - 7 APR 2000 => Playback of mode using "barrel roll" - 12 APR 2000 => Increase integration time to > 0.5 s - AUG 2000 => Decrease scan set-up time - AUG 2000 => Decrease synchronisation time to about 1 s for most scans - AUG 2000 Other high priority items are: Increase efficiency factor (still worse than MK3 for 1 pass) Stable track finding software (real soon) Remove station unit bugs Implement multiple correlation streams (late 2000) Increase number of useable playback drives to 8 (late 2000) Double-speed playback (extra equalizers planned) (late 2000) Dual LHC/RHC fringe-fitting in FOURFIT (late 2000) Implement FRNGEX (late 2000) Implementation of a data route into AIPS (early 2001) Multi-tone phase-cal Official opening of Bonn MK IV correlator ==> 17 November 2000 --------------------------------------- Playback Units -------------- Head wear has been reduced significantly by the implementation of dry air kits designed at MPI. Seven of the 9 drives had been modified to optimise replay of thin tape as this is in general more critical than that of thick tapes. Switchable equalizers are being developed to allow correlation at different tape speeds. MKIIIa Correlator ----------------- The MKIIIa correlator, introduced in 1988, was switched off on October 4th, ending an era of nearly 20 years of MKIII operations in Bonn for both astronomy - MPI and EVN - and geodesy. Availability of MPIfR MkIV Correlator for EVN observing ------------------------------------------------------ Although the EVN Data Processor at JIVE has taken over as the default correlator for the EVN, the MPIfR MkIV correlator will still be available, in principle, for limited processing of EVN observations. Suitable projects will be those for which the scientific advantage of using the MPIfR Correlator is given in the proposal, or those which include an MPIfR collaborator who wishes to have a closer "hands-on" approach to the data flow.