There has been excellent progress on installation of the ROAR boards (part of the on-dish calibration system, or ODC) with 20 antennas now completed. The commissioning of these ODC systems is progressing well, with integration testing revealing some inconsistencies between the software drivers and the final hardware revision that have since been fixed. We are also commissioning a "calibration correlator" module in the beamformer firmware that sits alongside the array co-variance matrix (ACM) engine and computes a single row of correlations (using a reference port that can be chosen at runtime) with full duty cycle. This is a small fraction of the computational load of the full ACM and the data file it produces is also much smaller, which should enable regular monitoring of the complex gains of all PAF elements.
At present, we are trying to accelerate the commissioning of these ODC systems on the main array so that they can be used to help reduce beamforming overheads during early science observations when they can resume.
Preparation of the vertex optical fibre link during ODC installation