EXTERNAL INSTRUMENT

The Engineering Development Array (1 & 2)

The Engineering Development Array (EDA) is a separate telescope designed and built by Curtin University, in parallel with AAVS, described here: The Engineering Development Array: A low frequency radio telescope utilising SKA precursor technology by Wayth et al (2017). It is a single field-node of 256 antennas, replicating the proposed antenna layout of the SKA_LOW field nodes, but using MWA dipole antennas instead of SKALA antennas. Data taken from the EDA is compared and correlated against the MWA.

As the MWA antennas have already been thoroughly characterised, the EDA helps us understand how a larger group of randomly spread antennas can be expected to perform in the given layout.

The EDA is located near the core of the MWA. The MWA amplifiers were improved for use in the EDA, so that the frequency range of the EDA is 50MHz- 300MHz.

The EDA was conceived, constructed and commissioned in less than a year.

The first version of the EDA, also called EDA-1, did not incorporate conversion of signal straight to fibre like AAVS; instead it uses 16 regular MWA beamformers on the ground-plane to transfer the signal data to a piece of equipment that acts like a receiver, called the Kaelus Beamformer.

The next stage, EDA-2, has been constructed one of the empty AAVS field node locations. Like EDA-1, it has 256 new MWA-style antennas with modified amplifiers, all situated on the ground-plane mesh. However, instead of using MWA beamformers, EDA-2 has 16 SMART boxes ('Small Modular Aggregation & RFoF Trunk'). Each SMART box contains front-end modules that convert the coaxial cable RF signal to fibre, suitable for sending to the control building. This happens via a Field Node Distribution Hub (FNDH); a large shielded container on the edge of the ground plane that delivers power to the SMART boxes (and thus, to each antenna) and aggregates their data signals into a combined fibre for easy transport.

This new system is designed to closely replicate the SKA Bridging Phase project, AAVS1.5, with MWA antennas instead of SKALA-4.1s, and will be an excellent comparison tool as well as a powerful telescope in its own right.