Performance and Reliability of the EVN;
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Session 2/2009 --------------


The session consisted of four frequency blocks (13/3.6 mm, 6cm, 5cm, & 18cm). 
NMEs including ftp fringe tests and calibration experiments
were performed in each block. The ftp data were processed in a 
semi-automated way. 
 


There were 19 user experiments (1 at 13/3.6cm, 7 at 6cm, 5 at 5cm, & 6 at 18cm) 
in the session. There were 14 Gbps expriments observed in the session. The Kunming 40m radio 
telescope partcipated in the NME experiment N09SX1. The fringes to the new 
Chinese station were successfully detected at S band. Furthermore, an extra user experiment 
(EY008A) was performed on 5-6 Aug 2009. The Miyun 50m radio telescope particpated in 
the experiment for the first time. The EVN fringes to the Miyun and Kunming stations 
were also detected at 3.6 cm.   


Station and correlator feedback for individual stations:

Ef - Stopped observing for about one hour in EG040C and for 45 minutes in EP063A 
because of a thunderstorm. Some RFIs mainly in the lower part of the band (between 1610 MHz 
and 1624 MHz) present during the whole 18cm session.


Wb - RFI at 1610.49 USB+LSB and 1632.49 LSB in Gbps experiments. Wb worked in phased array mode 
except for the 5 cm expepriments. TADUmax was also used with only one RT at 5 cm. TADUmax did not 
match the setup of the vex file in N09SX1 and EH023B, which caused polarisation swap in some 
subbands. 


Nt - Weights were zero from the start of the experiment upto the end of Scan 9 (upto 21:46) because Nt wasin the wrong recording mode, thus no data from Nt corelated for that time range and all the data for Nt was flagged in EB040A. No fringes in unlocked BBC
11 (IF 5&6) in EH023B. The amplitude of the upper 4 IFs/LL decays with increasing
frequency, only partially recovered after the post-correlation 2-bit van Vleck correction. 
This behavior seems characteristic of Nt in 6cm Gbps experiments.


On - No fringes in ES060A due to problem seting the correct LO (a Lantronix unit hanged). 


Tr - No fringes in EB040B (Tr ok in the preceding EB040A and the following ES060A-B). The sensitivity was lower 
than the expeted at in EP064G due to something wrong with the polariser-feed system. In the following observations EP063B,
Tr started about one hour late and solved the problem.  

Hh - No observations again in session 2/2009 due to the serious polar-mount
bearing problem.

Mc - Displayed tiny phase jumps in EP063B, ES060B, and EH023B. These jumps may be related to 
an instability in the H-maser due to overcurrent in some pumps. No finges in EG040D as a 
result of the incorrect LO (400MHz too low). Lost 2.5 hours data due to MK5A module failure in EH023B.

Ur - No fringes in Gbps experiments EM072A, and EP064E due to the over-rate recording. 
Used 1 bit sampling since 18:15 UT in EM072B to avoid the problem in the later Gbps experiments. 


Sh - S-shape phase bandpass and low correation amplitude in some BBCs.  

Ys - H-maser failure in the last four experiments (EG040F, EH023A, N09SX1, & EH023B).

Mh - No scheduled observations in session 2/2009.

Ro - No scheduled observations in session 2/2009. 
 
Jb - The Lovell telescope suffered a wheel casualty in the middle of
     the L-band session (2 experiments prior to EP063A), and was replaced 
     with Jb2 for the remainder of the L- & C-band experiments. 


Cm & Kn - Both shared one MK5A. The 14 MHz signal was fed into two subbands (7 MHz/subband) 
   instead of one subband in all the participated Gbps experiments at 6 and 18 cm. 


Ar - Participated in four experiments: EG040 A&B and EG040 D&E. Lost three quatres data
in EG040 B&E because Mark 5A lost connection with the FS.



Jun Yang for the Science Operations and Support Group (JIVE)