Ground Planes

ith the ground work reaching its final stages, it is time to start thinking about the installation of the aerials. This means organising the various components and moving them into place ready for deployment.

In the picture Dave King (left) and Mike Willis set down a stack of LBA ground planes.

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Sand People

Now that the HBA cables are in place and patched into the RF-container, the HBA cable grave can be filled in.

First a thick layer of protective sand is spread across the cables. The crew work the cables gently to ensure that the sand penetrates between all of them.


Here is the finished sand cover. This protects the cables against flint and other sharp rock as the spoil is back filled into the grave.


With all cables completely covered, the digger moves in to bulk fill with previously excavated material. And that is it! The HBA cables are fully covered and the crew can walk through the area without the risk of falling into the hole or collapsing a trench wall.


There have been many people involved in the laying of the HBA cables, and here are a just a few of them. From left to right: Dave King, Jon Eastment, Mike Willis, Alejo Martinez-Sansigre and Harry Smith. To these few, and everyone else involved in this stage of the project: thanks and well done!

A Fresh Grave

Just as the HBA cable work is coming to an end, the folks at Chilbolton are ramping up their efforts on the LBA. In preparation for the installation of the LBA cables, another large cable grave is prepared. The purpose of this is to take up the excess length in the cables before they are passed into the RF container. Like with the HBA cables, this excess length is a result of the fact that the cables are set lengths (for ease of manufacture and quality control), but the LBA antenna positions are at various different distances.

Here the diggers are working on putting sand at the bottom of the cable grave. The sand protects the cables against sharp flint pieces.


Here is the finished cable grave, ready for the LBA cables. Based on experiences with the HBA cable grave, we've opted for one slightly larger, to allow easier access. (Mike Willis has been included in the photograph to give you an idea of the scale.)

Disentanglement

One of the consequences of various tasks being ahead or behind the schedule is that the folks at Chilbolton have been forced to deploy all the HBA cables before the RF-Container was ready to accept them. This has been good in that they have been able to get the cables laid into the trenches without incurring further delays. On the other hand, they now need to sort out these cables to feed them in the correct order into the RF-container. Quite a task as you will see!

A bundle of cables... thankfully all electronically labelled. A barcode reader and some home-built software will quickly identify the antenna position associated with each cable.


Stuart Lynn, (our "All in the Gutter" live tweeter) Izabela Bukowska and Cristina Fernandes trace a cable in preparation for its deployment into the final trench to the RF-container.


The first cable pair reach the patch panel (Y & X polarisations for HBA antenna #95).


Alejo Martinez-Sansigre, Dave King and Mike Willis continue work on patching cables into the RF-container


Some more of the day's cable-team (left-to-right): Roger Deane, Cristina Fernandes, Alejo Martinez-Sansigre and Stuart Lynn.

Chilbolton Status Update for January

Ground Works

A contractor to start the ground works has not yet been found, party due to the first quote coming in to high, but also there has been some delay due to the uncertainty over STFC funding (which was cleared up this week). The project manager Mike Willis and other staff will meet new bidders at Chilbolton in early Feb. Work is now expected to commence in early March. It will be tight but we are still hoping to complete the ground work before the 1st of June. This work must be completed before any of the antennas can be installed.

LBA Installation

We are happy to announce that Gordon Brown (of STFC) will be taking on the job of co-ordinating the teams of volunteers at the time that the LBAs (low band antennas) are being deployed (and possibly also the high band antennas, HBAs). Mike Willis, the project manager for LOFAR at Chilbolton says "I would like to thank Gordon for taking on this task, I am sure it will go smoothly under his guidance."

(For LOFAR-UK astronomers, this is an edited summary of the reports from Mike Willis on 5th and 26th Jan which can be found in full on the main LOFAR-UK Wiki in the Restricted Section)