  We discuss absolute calibration strategies for Phase I of the Hydrogen Epoch
of Reionization Array (HERA), which aims to measure the cosmological 21 cm
signal from the Epoch of Reionization (EoR). HERA is a drift-scan array with a
10 degree wide field of view, meaning bright, well-characterized point source
transits are scarce. This, combined with HERA's redundant sampling of the uv
plane and the modest angular resolution of the Phase I instrument, make
traditional sky-based and self-calibration techniques difficult to implement
with high dynamic range. Nonetheless, in this work we demonstrate calibration
for HERA using point source catalogues and electromagnetic simulations of its
primary beam. We show that unmodeled diffuse flux and instrumental contaminants
can corrupt the gain solutions, and present a gain smoothing approach for
mitigating their impact on the 21 cm power spectrum. We also demonstrate a
hybrid sky and redundant calibration scheme and compare it to pure sky-based
calibration, showing only a marginal improvement to the gain solutions at
intermediate delay scales. Our work suggests that the HERA Phase I system can
be well-calibrated for a foreground-avoidance power spectrum estimator by
applying direction-independent gains with a small set of degrees of freedom
across the frequency and time axes.
