The arrival

The first lorries with LOFAR HBA tiles have arrived at the KAIRA site at Kilpisjärvi. They have travelled from the Netherlands to Lübeck, then a boat to Kemi, before driving up to Kilpisjärvi.

Two of these lorries arrived (actually the previous evening) and were ready to unload this morning. That made for a very frantic Monday-morning start, as we had originally anticipated at least a few hours this morning to clear the site, move vehicles and do the last patch of ground levelling.

Yet the work was done quickly and efficiently and unloading would soon be able to commence.

Each lorry contains four HBA tiles. The tiles are stored 'folded' for transportation. In this configuration, the are approximately 5 metres long, 1 metre wide and 2.5 metres high. In addition to the four folded tiles, each lorry also contains 4 pallets with 'tile lids'.

Although it takes up a huge volume, the load is quite light... just over 1 tonne. When we received the delivery of the test tiles for last winter, the drivers mentioned that the load can be tricky at times if driving in high winds.

Still, these have made it here safely and will be unloaded soon.

Photos: D. McKay-Bukowski

A sign of things to come

This week, we will start receiving a large number of deliveries. These will mostly be HBA tiles, but also some additional equipment will arrive and we also expect the work teams to arrive too. To assist the drivers find the site turn-off, a new roadside sign has been made. Definitely an improvement on the old one, which was a little bit difficult to see from a distance.

HBA installation progress

Over the course of the next few weeks, we will be installing the High-Band Array (HBA) tiles at KAIRA. Deliveries of the tiles will commence tomorrow (Monday 4^th July 2011) and continue to arrive at the rate of 4-5 lorries per week. Unloaded tiles will be stored at one end of the site ready for deployment.

Because we are mounting the entire HBA 1.5 metres above ground, our installation is somewhat different to a conventional LOFAR station. Instead of the usual sequence, we need to assemble each frameset first, then transport that onto the array. While this is being done, a tile antenna can be taken from the storage area, unpacked, unfolded and fitted out. Once the frameset is in position and is secured, the tile will be transported to it and secured on top.

In order to monitor the progress of the build, we will be updating the progress map each day. We haven't commenced the installation just yet, but here's the 'blank' map to act as a starting reference.As tiles are deployed, their positions will be shaded in on the map. Antenna sites which have framesets will also be marked and the tally of how many are installed will be updated accordingly.

A new update will be posted every evening from now until the build is completed, so you can check progress at the end of each day (or when you wake the next morning).

Lehtinen Barracks on the move

Because the site is remote from SGO, it is important to have sufficient facilities to run experiments. There will actually be several units on the site. Apart from the RF-container which will house the KAIRA signal processing, there will be a storage container for spare parts and surplus materiel and a mobile cabin... which has been affectionately dubbed the "Lehtinen Barracks".

The "Lehtinen Barracks" is built from an old Finnish railway (VR Suomi) carriage. It has now been refurbished and is on its way to Kilpisjärvi to serve as office quarters at the KAIRA site.



The video shows the old VR Suomi marking, the refurbished cabin leaving the institute and a final shot of it having arrived on site. No doubt, there'll be some more photographs over the next few weeks as the final fitting out has been done and the final placement made.

PS: I wonder if this is the furthest north Finnish railway stock has ever travelled?

Video: Juha Vierinen

Power poles

The main power line to the KAIRA site has now been completed and has been energised. This brings the mains across to the south edge of the HBA field. It is done using tall timber poles to avoid too much disruption to the native ground cover and to make maintenance and deployment easier.

At this point there is the final power pole, and a connection down to a termination box. From there the cable needs to go underground for the rest of the way to the central site power point (which is located in the RF-container). The underground cable has been buried in, but it has not yet been connected, as the termination at the RF-container end has not yet been installed.



Because of the sensitivity of the array, it is essential that the electrical power line be kept out of the way on the final approach to the site. This is not just because it carries power, but because it is a long metal object. This reflects radio waves, which can cause confusion in the final images.

The same applies to other metal objects. They have to be kept away from the array as much as possible to minimise these reflections.

Even the reflections of astronomical radio sources (such as Cas A, Cyg A, etc.) can cause spurious images ('ghosting') to appear in the data.

First frameset

The first 'real' frameset for the installation has been assembled (although it has not yet been lifted into place). The main objective here was not quite to get the frameset itself built, but to practice the technique and ensure that the auxiliary equipment, templates and rigs were working.


Each frameset comprises seven frames. Five of these are 4900mm long and align in one direction at a spacing of 1250mm. The other two frames in the set are 5000mm long and go in a cross-wise direction to the others.

See also: http://kaira.sgo.fi/2011/06/frames.html

Digger tracks

Late on Thursday, there was an interesting cloud formation, that rolled down of the Norwegian mountains and swept across Siilasjärvi like some sort of raised serpent. I captured part of it, looking over the great metal tracks of the 18-tonne digger. It makes a nice dramatic photograph to end the week. On Monday, we commence the installation of the HBA tiles... so expect a LOT of updates next week.

Have a nice weekend!