  We describe the design and performance of the Engineering Development Array
(EDA), which is a low frequency radio telescope comprising 256
dual-polarisation dipole antennas working as a phased-array. The EDA was
conceived of, developed, and deployed in just 18 months via re-use of Square
Kilometre Array (SKA) precursor technology and expertise, specifically from the
Murchison Widefield Array (MWA) radio telescope. Using drift scans and a model
for the sky brightness temperature at low frequencies, we have derived the
EDA's receiver temperature as a function of frequency. The EDA is shown to be
sky-noise limited over most of the frequency range measured between 60 and 240
MHz. By using the EDA in interferometric mode with the MWA, we used calibrated
visibilities to measure the absolute sensitivity of the array. The measured
array sensitivity matches very well with a model based on the array layout and
measured receiver temperature. The results demonstrate the practicality and
feasibility of using MWA-style precursor technology for SKA-scale stations. The
modular architecture of the EDA allows upgrades to the array to be rolled out
in a staged approach. Future improvements to the EDA include replacing the
second stage beamformer with a fully digital system, and to transition to using
RF-over-fibre for the signal output from first stage beamformers.
