Digging out

I need a spanner.

It's in the storage container.

But the storage container has a great pile of ice packed against the door.

So, I'll need to dig it out.

With a shovel.

Which is in the storage container.

:-\

That was the grey storage container (which you can see, complete with snow pile in one of yesterday's photographs). So what are the chances of needing something from the other storage container in the same trip? Well, pretty high, apparently. At least this time I have a shovel. It is a bleak task to have to do it by hand.

Time to dig my way into the other container (Photo: D. McKay-Bukowski)

Sky above, snow beneath

Today we have another photograph of the snow conditions at the KAIRA site:

HBA, RF-container, site office and one of the storage containers.
Oh, and plenty of fresh snow too. (Photo: D. McKay-Bukowski)

Trained containers

On the site there are a few storage containers, used for spare parts and crates and the like. They are lined up along the north-eastern part of the site.

Containers at theKAIRA site. (Photo: D. McKay-Bukowski)

When caught in the evening sun, the looked a bit like a railway train. The thing is though, the barracks (on the left) is actually an ex-railway carriage.

Moved storage

In order to build the Low-Band Array, the storage containers need to be moved from their original locations. The new location is by the service road that runs along the northern edge of the High-Band Array.

The storage containers in their new locations. Photo: Joona.

These contains have various boxes and parts that are either left-over from the build or are needed for when the main antenna deliveries arrive.

Site storage

Site work continues, including inspections of the crates, containers and other facilities.

The two storage containers.

Stockpiles of supplies for the LBA installation, as well as some leftover boxes.

These two containers will be moved when building works start on the LBA array itself. The shipping contains were icy-cold, but still in good condition and the few supplies therein were okay.

Electronics and cables

As part of the recent delivery, we received a lot of electronics, cables and ancillary equipment. We spent a bit of time moving things around and getting organised for the week.

Santtu Rantakokko and Marko Kauranen shift the sub-rack
assemblies from the Land Cruiser into the auxiliary container.

In addition to the electronics, there are a lot of cables. In fact a total of 576 signal cables were delivered, with a total length of 27268 metres!

Of that distance, 96 cables (nearly 10 km in total) will be deployed as soon as possible onto the HBA field. The remaining cables are either for the RF-container or for the LBA installation for next year. Although the quality of the supplied cables, we checked every single one for the signal attenuation and group delay to ensure that it is correct before taking it over to the RF-container for installation.

Juha Vierinen uses the network analyser to check one of the cables.
This work is being done in the so-called Lehtinen Barracks.

We spent a couple of evenings and one work day sorting out the measurement technique and then checking all the HBA field cables. The work went very quickly and the team's progress was outstanding.

Once the testing was completed the cables were taken out to the RF-container where they are stacked ready for feeding through the cable ducts to connect to the antennas.

Santtu Rantakokko and Juha Vierinen unload cables from the Land Cruiser to the RF-container.

Stacks of 115m cables in the RF-container, ready to go!

Auxiliary container

The next item on the delivery lorry for 25th July 2011, was the auxiliary container.


This container provides additional storage. It also came with various pieces of equipment inside that would be needed for the installation.



Unlike the RF-container, unloading and placing this was pretty straight-forward. However, the following load proved to be difficult and dangerous. Stay tuned!

Photos: D. McKay-Bukowski

Unloading the lids

On each HBA tile, there are polystyrene 'lids' — one for each of the 16 cells that hold the antenna elements. These are not on the tile when it is folded, so are shipped on separate pallets (although often on the same delivery lorry). These pallets also need to be unloaded and stored.



Because they are quite tall, and are very light, it is important that they are secured against the high winds that often occur at the Kilpisjärvi site.

Photo: D. McKay-Bukowski

Tile stack

When stored, the tiles are placed neatly against one another. This allows them to provide mutual support to each other in the event of strong wind gusts. The end of the 'stack' rests against either the storage container or the Lehtinen Barracks. A retaining strap goes around the tiles and across a frame which is placed at the end for further support.


Each tile has a covering sheet of clear plastic and is then wrapped around with what is essentially a large piece of clingfilm.

This view is quite good to show the individual antenna cells in each tile. There are 16 cells in total, but when folded in its storage container, only half of them are visible from one side.

Photo: D. McKay-Bukowski

Storage stacks

This photograph shows the arrangement for storing the tiles. On the right is the 'storage container' (a converted shipping container). There are three tiles resting against it (the spare tile, and two new ones).


The Lehtinen Barracks stands higher and can be seen behind the stored tiles (although they are not resting on it per se). The barracks are also used as a resting point for tiles and tile lids. In the left background, there is a partially unloaded lorry and further back (behind the trees on the main road), there is another lorry waiting to come on to the site.

Moving the ground tile — Part 2

Once the tile is lifted, it needs to be carefully driven across to the final storage location. This was done by simply driving the lorry with the HIAB (vehicle-mounted crane) over the final location. This was very risky for the tile. The lorry does not have extra-soft suspension and there is no shock-absorbency in the lifting rig. The move was complicated by the (comparatively) rugged terrain and the fact that the breeze was stiffening.

Still, we managed to move it without losing any components and then set it down onto a prepared pallet which would act as a storage base.

The HBA tile touches down on its storage location.

At this point, the tile remains very fragile, so it needs to be secured right away. A tarpaulin was quickly placed over the tile to contain the parts and provide the inner layer of protection. Then a timber frame was put in place to provide structural stability.

Shoring timber is applied to support the tile.

Once that has been done, then the external covers are applied and the system pegged down. The lids are stacked alongside and are also covered and secured.

Nearing completion. Additional covers are applied and tile lids are stored.

Some additional clearing and securing was then done and now the tile is in a safe state to endure until possible requirement during the main HBA build, or even perhaps the future expansion of the KAIRA system.


Photos: D. McKay-Bukowski

Moving the ground tile — Part 1

As we know from the various photographs and reports, there are (were!) actually two test tiles at the site. Obviously, our recent series has focused on the destruction of the raised tile.

But what of the ground tile?

We want to move this tile off the main build area. We need to get it out of the way so we can build the main array. It is also an 'empty tile' in that there are no electronics or receiver elements embedded in it.

On the other hand, we want to keep the tile, as it is both useful as a source of parts, but also as a possible 'centre-tile' in the case we upgrade to an international station size for the KAIRA HBA.

Therefore, we decided to move the tile, pack it, and store it on the site.

The first step in this process is to remove the cover of the tile and all the solid polystyrene lids. These are stored separately. This leaves the tile vulnerable, with all the delicate parts exposed, so we need be careful now.

This is the tile with the cover removed. It clearly shows the pristine polystyrene structure.

Once the tile is ready, it can be refolded. So often, we hear about unfolding the tiles, as reported on other web sites about other LOFAR stations. However, as far as we know, this is the first time a tile has been re-folded in the field. (We'll ignore the manufacturing set-up which has the facility to fold the tiles as they are built.)

Then we prepare to lift the tile.

It is at this point that we are ready to lift the tile. Normally during unfolding, there are batons, wrapping and straps. As we are refolding, there is none of this. We didn't even have a correct centre beam, as the main LOFAR tooling is currently in use in Sweden on the SE607 build.

HBA tile being lifted

Once lifted, the tile can then be refolded and moved. We did not have the possibility to load the tile onto a pallet, nor do we have the straps or batons to secure the individual components. They are held in place at this 'unexpected' angle by gravity and gentle nudging by the team.

Nervous moments: the tile parts totter precariously in the breeze.

What happened next will be explained in tomorrow's report.


Photos: D.McKay-Bukowski

Preparation work

The idea was to deploy the tiles before the first winter snows arrived. And although there was some scattered patches of snow on the ground when the team arrived, it certainly wasn't anything prohibitive.


The first step for placing the two test tiles was to level the patches of ground where the tiles would go. This was done with the help of a laser level (see here glaring into the camera lens).


Once the two areas were level, the frames could be assembled on the northern patch. As explained in an earlier post, we intend to put out two tiles. One will go on a raised platform made of open timbre frames, and the other will go directly to the ground (like in conventional LOFAR stations).

Once the frames were put in place, we took delivery of the tiles themselves. These arrived on an articulated lorry and were unloaded in the afternoon.

When packed, the tiles are stood vertically, folded over. At 5 metres long, and 2.5 metres high, they are actually quite vulnerable in this position. As a result, we quickly assembled a support frame that would secure them overnight, ready for tomorrow's deployment.