EDGES-3: Instrument Design and Commissioning

EDGES-3 is the third iteration of the Experiment to Detect the Global EoR Signature (EDGES) experiment, designed to measure the predicted global absorption feature in the radio spectrum produced by neutral hydrogen gas at cosmic dawn, a critical observation determining when and how the first stars populated the universe. The EDGES-3 instrument has been redesigned to include both the analog and digital electronics within the antenna, allowing for in-situ calibration and removal of the lossy balun found in EDGES-2. EDGES-3 has been on multiple deployments in the past 4 yr; to Oregon, Devon Island, Adak Island, and is currently installed and taking data in the outback of Western Australia. This paper provides an accounting of the challenges inherent in the detection of the global, cosmological 21 cm signal, the strategies EDGES employs to mitigate each of these challenges, a description of the instrument, and a report on the Western Australia deployment along with observational data.