KAT-7 (prototype) system engineering update

	Diagram of KAT-7 system
	CAD image of completed KAT-7 antenna
	Testing of feed horn
	Mounted feed package
	DBE Roach Board

Antennas

The pedestals and other components of the seven KAT-7 prototype antennas have been delivered to the telescope site in the Karoo during June 2009. The team commissioned and assembled an industrialization model in Pretoria in order to minimize the amount of work that will be required on site. The dishes will be moulded on site on a mould that has been set up to an accuracy of 0.5 mm. The first fully tested and commissioned antenna will be handed over to SKA South Africa by the contractor BAE in early August 2009.

Feeds and cryogenic system

The design and development on the feed and cryogenic system have been completed. The horn was tested at a testing range and actual vs. theoretical performance correlated very well. An innovative OMT (orthogonal mode transducer) design meant that weight budgets could be achieved. A significant amount of development went into the design and manufacturing of the cryogenic system. A test unit that has been running for months provides a high level of confidence that the cryogenic system will perform as specified.

Radio Front End (RFE)

Design reviews have been completed for all the "stages" of the RFE system. The next step is to get an integrated system in the lab to do performance testing prior to integrating with other subsystems or integrating in the Karoo. Tests at temperatures below what is expected in the Karoo (tested to 50K, while 70K is expected) proved that the Low Noise Amplifier, integrated with the cryogenic system, perform as predicted.

Digital Back End (DBE)

SKA South Africa collaborates with the University of California at Berkeley in the ROACH development. In return for our contribution to the design work, the South African project will get a percentage of the boards once they have been manufactured. The hardware required for the first two working antennas (the so-called "fringe finder") has been delivered and early testing on that has started. The aim is to test these boards on the GMRT during June/July 2009 prior to integrating them into the fringe finder system. In preparation for producing the boards for the KAT-7 hardware, the last manufacturing issues on the DBE are currently being ironed out.

Software development

Since software is the "glue" that keeps the system together, the software group continually interacts with the rest of the technical team and scientists to ensure that the software will cater for everybody's needs and will be what scientists expect. It is expected that a fully simulated system will be up and running by the end of June. The group has also been working on ways to process the large amounts of data from MeerKAT in real time and on simulations to predict performance from antennas based on their beam patterns and mount types.

XDM (Single prototype dish at HartRAO)

A significant amount of effort has gone into finalizing the work on XDM to ensure that the team get the learning from the prototype that we set out to do, and documenting these learning outcomes. This has provided valuable insight into testing of subsystems prior to deployment and yielded a new understanding of the level of engineering and concept exploration required to get a system running efficiently and reliably.