Tuesday, 17 April 2012

Corner of the site

Today we have just a nice photograph. Taken on the verge of winter, this photograph shows the northern corner of the site. In the distance the midday sun is just glinting on the summits of the Norwegian mountains. The reindeer fence is still visible and a couple of the LBA test station platforms can be seen.


Saturday, 14 April 2012

Reindeer fence

We continue our series of web log posts about work completed at the end of last year. Although we've been really busy over the winter, we've almost caught up with all the news ready for the next stage of the build this season.

Of course, one of the distinctive features of the KAIRA site is the beautiful wildlife. However, we do need to protect our sensitive experiment from the animals that roams these northern wilds.

As mentioned last year, there was a reindeer fence that was installed around the full site perimeter. The following photograph (by Arttu Jutila) shows the site layout, with a faint yellow line marking the proposed route of the so-called reindeer fence.

As we mentioned the posts for this were installed last summer and the wire spooled out from post to post to secure the area. Here is the wire deployment rig.

Finally, some gate lines were added along the route to permit access. Here is the main entrance during construction last autumn.

As you can see, the snow had started to set in back then. Of course throughout the winter it has been totally covered in snow. Note also the reflective markers. The fence itself is also marked to make it distinct in critical areas. As we also mentioned in a previous post, there are also snow poles around the area to mark difficult or dangerous terrain that may be hidden under the snow and ice.

Tuesday, 10 April 2012

First summator!

Almost first light! On November 11th 2011 we installed the first two summators into the HBA panels with the idea that these can be used to test the signal processing hardware inside the RF container. These summators were the first from the newly designed batch of summators produced by Astron, hopefully fixing some of the problems with moisture that were experienced with the old version. The wintering of these newly designed summators will also be a test of their durability as well. 

We are still missing 46 summators before the system is fully operational. However, we will have to wait until spring 2012, as it isn't possible to perform the installation during winter due to increased risk of static electricity discharge and pure inconvenience. 

The green cables seen inside the HBA tile are connected to the summator, which is responsible for the first level of coarse grained beam forming, implemented using a set of switchable delay lines.    

Installing the summators.

Thursday, 5 April 2012

Prototype LBA platforms

As we did with the HBA platform in 2010, we also decided to try out several different prototypes of the LBA antenna platforms in 2011. This is mainly because the terrain at the planned location for the LBA field is even more unstable than the land under the HBA field. In the end, we ended up with three different prototypes. The wintering of these prototypes will tell us about the ground movements caused by permafrost, and also give us some experience on the rigidity of these designs. 

Earlier on, this approach was also investigated by modeling the effect of the raised ground mesh to the single element beam pattern. 

1.0 Simple platform reminiscent of the HBA platform. 

2.0. Turnable ground plane and three height adjustable legs. 

3.0 Turnable ground plane, anchored and adjustable legs.