  The wide adoption of low-frequency radio interferometers as a tool for deeper
and higher resolution astronomical observations has revolutionised radio
astronomy. Despite their construction from static, relatively simple dipoles,
the sheer number of distinct elements introduces new, complicated instrumental
effects. Their necessary remote locations exacerbate failure rates, while
electronic interactions between the many adjacent receiving elements can lead
to non-trivial instrumental effects. The Murchison Widefield Array (MWA)
employs phased array antenna elements (tiles), which improve collecting area at
the expense of complex beam shapes. Advanced electromagnetic simulations have
produced the Fully Embedded Element (FEE) simulated beam model which has been
highly successful in describing the ideal beam response of MWA antennas. This
work focuses on the relatively unexplored aspect of various in-situ,
environmental perturbations to beam models and represents the first
large-scale, in-situ, all-sky measurement of MWA beam shapes at multiple
polarizations and pointings. Our satellite based beam measurement approach
enables all-sky beam response measurements with a dynamic range of \sim 50 dB,
at 137 MHz.
