Westerbork station report

Thu, Jun 30, 05

This is a short summary of what has happened since November 2004

System

A new air-conditioning system was installed in April 2005. This has already proved better than the old one, as the backend continued working even when the outside temperature rose above 34° on 24^th June. The added capacity allows us to install more equipment and the temperature stability is much better than before.
To allow the placement of the new air conditioning we had to move and recable all the VLBI equipment
A new Faraday cage has been installed for most of the online computers. This was done to reduce RFI at Lband and lower frequencies from the control building itself
Since 27^th June we have a new time and LO distribution system for the backends.

VLBI equipment

We received a new Field System computer shortly before session 2005-2. It has not yet been taking into operational use
We have ordered 15 more empty disk packs from Conduant. We have already provided 56Tbytes of packs to the EVN.
The tape recorder has given lots of problems with vacuum loss. The brushless variable speed motor failed, and we replaced this with older carbon brush version. This also had problems with the dry bearings, and the last tape we recorded (June 2005) gave vacuum loss 3 times -despite coming through prepassing.

Sessions

Session 2005-1

Any resemblance to real characters are purely imaginary!

We had some snow at the start of March 2005. For one day it was impossible to move in or out of the observatory, so the telescope operator was stuck there. Several of the telescopes got stuck as the large quantity of snow made the out of balance and some of the safety limits switches were also triggered. System temperatures were raised and the effective aperture also decreased – so the SEFD was very badly affected. Phasing up the array was also much more difficult

Session 2005-2

There were some problems with the Mark5A systems freezing up. These were most effectively dealt with by rebooting the system