Westerbork VLBI  report for the TOG in Arecibo at August 29 2011 
====================================================================================

Regular Session Participation:

	Westerbork participated in the M,C,P and L-band experiments of
	session 2011-1 and 2011-2.  Observing was successful.
	FTP fringe files were produced by the system, and fringes were
        found on all occasions.

        For the first time we participated in a 92cm VLBI session, using
        our MFFE receivers and digital backend. Extra effort was made
        to develop TuneUp software to phase up the array for this wavelength.
        The msxydif software, that uses the receiver noise sources
        to difine the phase difference between the X-Y channels has been
        commissioned also for 92cm. Also a model was defined of a
        suitable  92cm polarized calibration source.

        For session 2011-1 we lost 45 minutes out of 232 hours recording time
        
	problems that caused losses:
 
	- mark5b sync error                  (04m) 
	- Backend reboots/restarts           (23m)
	- 1x bad diskpack related problems.  (18m)

        For session 2011-2 we lost 5h 02m out of 234.4 hours recording time
        
	problems that caused losses:

	- Field system time jump problem                (68m) 
	- CtrlDzb delayed by too much network traffic.  (99m)
	- 1x bad diskpack related problems.             (14m)
	- Correlator power supply problems             (121m) 


e-VLBI: 
        In general Westerbork performed well.  
        e-VLBI was also used as part of session 2011-1.
        The transition from diskpack recording mode to eVLBI, and back,
	gave no problems.  

        

WSRT Backend: 

	Our digital vlbi backend (TADUmax) worked fine.
        It was used both for single dish (RT7), as the tied array
        (RT01234.6789abcd).
        We had some trouble with correlator power supplies. 



Field System:

        For both sessions we used FSL8 (Lenny)+ FS-9.10.4
	At 2011.152.00:23 UT our FieldSystem time jumped to 2010.020.21:57 . 
        This happened although the system was rebooted 2 weeks before.
        We lost more than one hour observing time because of this.      

Mark5B: 

	For session 2011-1 we used SDK8.2 + Firmware version 12.06
	After that we upgraded the firmware to 12.13 on request of JIVE,
        because the old firmware had a bug that made it impossible
        to use their new eVLBI software version.
        Session 2011-2 worked ok with this firmware.
        For session 2011-1 both pata and sata diskpacks were used.
        For session 2011-2 only pata diskpacks were used.                

        Current versions:
        DIMINO   : Mark5B DIM : 2007y222d04h : 1 : mark5-XX : 1 : 1 : 2.7x : 0x1b : 0x5bdb
        Linux    : Etch  2.6.18-6-686:(Debian 2.6.18.dfsg.1-26etch2) 
        Firmware : 12.13


Other: 

	New software has been developed to reduce data in Measurement Sets,
	supplied by the WSRT correlator, into ANTAB files.
	This software replaces a whole suite of scripts and time consuming procedures.
        A preliminary version was used for session 2011-1 and the final version	for session 2011-2.
        The complete documentation can be found in the WSRT wiki.


 




Geert Kuper. 29-6-2011