ILT-TO meeting April 11, 2011 (ILT Technical Operations)

The ILT Technical Operations meeting is held at the start of a LOFAR observing semester. The purpose of the meeting is to discuss operations procedures for the ILT, covering all aspects from observation scheduling to station maintenance. The audience for this meeting consists of (technical) personnel involved in running and maintaining the station.

This second meeting was held on April 11, 2011, at ASTRON in Dwingeloo.

Meeting presentation (Harm Munk)

All but the Onsala stations have been built. The LBAs at the Jülich station have been installed late in April 2011.

A sixth German station will be built near Bieleveld, probably in 2012.

eVLBI will require approximately 4 Gb/s bandwidth. That will not leave sufficient bandwidth for two international stations to share the same 10 Gb/s fibre to Groningen. Changing the number of beamlets on the fly will not reduce bandwidth: it merely pads the unused channels with zeroes.

Having sufficient bandwidth to connect all international stations at the same time would enable the study of ionospheric effects.

While installing the LOFAR software at Jülich, in casu NDPPP, it was found that the software was designed for single user clusters: if run on a multi-user cluster the software breaks because it has to compete for computing resources with other jobs.

The LBA's were installed in 2007, the HBA's in 2009. In December 2010 the Rb-clock broke down. After replacing the Rb-clock, no fringes have been observed with DE601. Also, pulsars could not be observed but this might be due to a software problem.

Eight apparently broken RCU boards have been tested at ASTRON and appear to be functioning correctly. The problem is now being investigated in Effelsberg again. It has been decided not to replace the RCU boards in Effelsberg (they lack overvoltage protection on the antenna inputs, which poses a risk especially at low humidity.)

The humidity in the container can become very low during cold winternights because of the heater. A humidifyer will be installed. The airconditionnig unit will not work below 18 degrees centigrade. A humidity below 20% is a potential hazard.

ASTRON will develop an application for monitoring the container humidity.

Several HBAs are still broken. ASTRON will repair these tiles.

Several weeks ago a wrong configuration got loaded which shut the HBA part down.

Often used for long baselines experiments.

A temperature monitoring facility is requested for this station as well.

Network connection up to recently troublesome, but seems ok now.

Some damage due to wild boars. Protection against beech martens (or stone martens) around the LBA wires have been installed. Unknown if that changes the electrical characteristics of the antennae.

A wooden fence has been installed.

Drainage has been improved.

LBAs will be installed in the week of April 18-22.

Cable over-length pit will be filled up soon afterwards.

Instead of trenches, the whole filed has been excavated for the cables.