  This paper presents a framework to compute the receiver noise temperature
(Trcv) of two low-frequency radio telescopes, the Murchison Widefield Array
(MWA) and the Engineering Development Array (EDA). The MWA was selected because
it is the only operational low-frequency Square Kilometre Array (SKA) precursor
at the Murchison Radio-astronomy Observatory, while the EDA was selected
because it mimics the proposed SKA-Low station size and configuration. It will
demonstrated that the use of an existing power wave based framework for noise
characterization of multiport amplifiers is sufficiently general to evaluate
Trcv of phased arrays. The calculation of Trcv was done using a combination of
measured noise parameters of the low-noise amplifier (LNA) and simulated
S-parameters of the arrays. The calculated values were compared to measured
results obtained via astronomical observation and both results are found to be
in agreement. Such verification is lacking in current literature. It was shown
that the receiver noise temperatures of both arrays are lower when compared to
a single isolated element. This is caused by the increase in mutual coupling
within the array which is discussed in depth in this paper.
