Message 4/504 Mike Garrett Oct 17, 2000 03:50:37 pm +0200 Date: Tue, 17 Oct 2000 15:50:37 +0200 (MET DST) X-Sender: mag@juw05 To: evntech@jb.man.ac.uk Subject: EVNtech: EVN Reliability and Performance Sender: owner-evntech@jb.man.ac.uk Precedence: bulk EVN Performance and Reliability - M.A. Garrett. This report covers the period: session 2 and session 3 2000. In the main, the performance and reliability seems to have been good over the course of the last 6 months. Its particularly nice to report that Torun has contibuted solidly to both session 2 and 3 - reasonable recording (track 6 repaired!) and reliable operations. A successful S/X session involving geodetic stations was conducted in session 2. There were fringes to all the geodetic antennas in the NME (including Ny Alesund). Hartebeestoek participated in several EVN sessions during the year and enhanced the capabilities of the EVN in several important areas, including 5cm observations. WSRT continued to perform well, with consistent high sensivity in phased array mode (30 Jy at L-band, 70 Jy at C-band; [c.f. 300 Jy for a 25-m antenna with good rx]). Onsala, Effelsberg, Jodrell, Medician and Noto continued to perform well. All in all, a significant improvement over the situtation that existed perhaps 3 or 4 years ago. Of course we must be vigilent... So as usual I will dwell on the problems... (and as it turns out some related successes). Shanghai and Urumqi -------------------- After the last TOG the most urgent concern was the performance of the Chinese antennas after their upgrade to MkIV/VLBA4 systems. This upgrade was only accomplished due to the tremendous efforts (well beyond the call of duty) of Team China (see reports by Wunderlich and Himwich) and the preseverene and skill of local Chinese experts (with help from Gino Tucarri after Team China had departed). Unfortunately no fringes were found at JIVE from the Team China test expts or the NME expts correlated in session 2, 2000. Another test experiment was organised by Tucarri and tentative fringes were found for Shanghai but not Urumqi. The current status (via the NME reports see Sjouwerman et al. www.jive.nl/~sjouwerm/summary00_okay.ps for a summary) shows fringes from both stations in session 3, 2000 (see also EVNtech report posted by Gabuzda). We are hopefull that both stations are now able to conduct standard MkIV observations with the EVN. Having both telescopes "MkIV capable" represents an important new capability for the EVN w.r.t. high resolution imaging. Other Problems: ---------------- * Swapped Polarisation at 6 GHz at Effelsberg (known at the time of observations) and Torun (discovered at correlation) - see report by Sjouwerman, session 3, 2000. Fortunately all the expts recorded in dual-polarisation mode so no data was lost. Nevertheless, it shows that this problem has yet to be completely irradicated (especially at freqs requiring a receiver change). * Some problems with Cambridge, no fringes in GR021. Suspected problem with switching of band from LCP only (2 x 16MHz) to dual LCP/RCP (2 x 16 MHz). Fringe tests made during session 3 indicate the problem may now be rectified. Tests continue (see report by Burgess). Minor Problem: * Problems with VC4 at JB (low amps) in session 2/3, 2000 - now rectified - see report by Burgess. Notes: * WSRT was not able to participate fully in session 3, 2000 due to the IVC upgrade. * Medicina was unavailable in session 3 due to track upgrade. ------------------------------------------------------------------------ Mike Garrett (garrett@jive.nl & www.jive.nl/~mag) EVN Support Group _______ ________ Joint Institute for VLBI in Europe / / _/ | / / ____/ Postbus 2, 7990 AA Dwingeloo, NL. __ / // / | | / / __/ Phone (office): +31 (0)521 596511 / /_/ // / | |/ / /___ Mobile: +31 (0)621 201417 ____/___/ |___/_____/ Fax: +31 (0)521 597332 "Donald Dewar's death has left an aching void in the hearts of his friends and the whole of Scotland. The country has lost one of its finest politicians this century and Scottish life is diminished as a result. It will be a long time before we see his like again." - Menzies Campbell's tribute to the First Minister for Scotland, DONALD DEWAR (1937-2000).