ESG report for the CBD, 2006 May


Performance and Reliability of the EVN
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Session 2/2006
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There were four band sessions, each with either a pre-session ftp test, or an
NME including an ftp test. The ftp fringe test data were processed in a fully
automated way, with minimal support scientist interaction except in compiling
the written reports sent to the stations (first reports were less than 2 hours
after the start of the experiment). The importance of fringe tests was shown
when a problem with Onsala VC03 was identified during F06M2. Standard station
tests indicated the VC to be working properly and the problem was only
identified after the VC was removed from the rack and analysed in the lab.

Urumqi withdrew from the UHF observations in session 2 due to commitments with
the Chinese space program. Unfortunately the withdrawal came too late to alert
PIs before the schedule deadline.

UHF experiments in general were badly hit by RFI. However, some parts of the
UHF spectrum are clean enough to allow useful data to be obtained.

Several reports were made of brief data losses due to problems with either Mk5s
or FS control computers which required rebooting. There were also occasional
losses due to bad disk packs (noticed more frequently during Gbps recording).
Overall scale of these losses was small.

The pipeline has been replaced with a new, easier-to-use version written in 
ParselTongue. 


Station and correlator feedback for individual stations:

Cm - Data throttling reported in EP056B, and no replacement disks were
available.

Ef - UHF experiments severely affected by RFI. 21 cm experiments also affected
by RFI. GM062B (21cm) affected by loss of one formatter track (formatter was
quickly replaced).

Wb - Some RFI observed at UHF. GD021A was partially observed with the wrong
setup (several subbands were lost for about 4 hours) due to an error in editing
the procedure file.

Jb - Reported need to restart the FS several times with a resulting small loss
of data.

On - UHF experiments severely affected by RFI. 21 cm experiments also affected
by RFI. Developed a problem with VC03 that was identified during F06M2 ftp
fringe test. This took some time to fix as the problem could not be identified
at the station until the BBC was removed to the lab (normal tests in the rack
indicated no problem).

Mc - ES056B lost about 2 hours due to a communication failure between the ACU
and the station computer which caused the FS to freeze.

Nt - OK

Tr - UHF experiments severely affected by RFI. During 5 cm session the power
supply to the receiver failed several times.


Ur - Did not participate in UHF experiments.

Sh - OK

Hh - OK

Ar - OK


Cormac Reynolds for the Science Operations and Support Group (JIVE)