SSSM in Argentina, a midway report.
10.12.05

Seen from the North, the station is located in the bus on the left, the three antenna masts next to it. On the right is the local team’s station. In the distance the CASLEO optical telescope and the Andes range. The snowcapped Andes mountains never fail to take your breath away.

After visiting the prospective sites in South Africa, China and Australia, the team consisting of Rob Millenaar and Bou Schipper, both of ASTRON, set course for Argentina to execute the last measurement session.

After Australia, by mid November the equipment was ready for shipment to the last of the four continents. The two crates were picked up in Dwingeloo and sent off, and some days later the team followed. Because of troubles at customs the delivery of the equipment at the site was delayed considerably. The team members had to wait for their goods to arrive, and in the meantime they made the best of the situation by paying a visit to another large scale international facility: the Pierre Auger Observatory, which is now nearing completion nearby in Argentina. The PAO is doing research on cosmic rays, at the other end of the radiation energy scale as compared to the SKA.

When the equipment finally arrived it was quickly unpacked, assembled and tested at the site. It was found to be in sound condition and the scheduled series of measurements could commence. One of the first things to do is a quick assessment of the radio interference situation at the site. This is to prevent doing measurements in the presence of avoidable locally generated interference. This would paint an unjustifiable negative picture of any site. Surprisingly, a great number of signals were found in the lower parts of the spectrum.

This antenna mast was featured in previous reports of site measurements. It now models in front of the Andes.

Subsequent investigations made it clear that at least some of the interference was generated by the local team’s equipment. Building a system that confines the stray radiation within the system’s enclosure is a rather difficult task and it was shown that here some improvements need to be made. It was agreed that the local team’s system was going to be switched off for the duration of the measurements at lower frequencies.

The site is bone-dry at 2500 meters elevation. This leads to interesting situations. The winds may be strong here and in combination with the low humidity this can lead to static charge build-up on the antennas. In turn, this may cause the destruction of sensitive amplifiers. Indeed, this has happened twice now. The problems could be fixed by installing spare amplifiers, but lessons can be learned here tor the case the SKA would come to this harsh, but beautiful place. And beautiful it certainly is!

The site is a high valley almost entirely enclosed in mountains and hills that are part of the pre-Andes range. A lower valley lies to the West, and beyond that the majestic Andes range always forms the impressive backdrop for the scenery. It is a privilege to be able to work in such a wonderful landscape, even though the dry atmosphere makes it uncomfortable at times.

Because of the delays in transport and by problems encountered at the site it will not be possible to finish the work before Christmas. The team members will suspend operations before that and continue early January.

Rob Millenaar
CASLEO site, Argentina, 10 December 2005

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