  Here we propose a minimal analog gravity setup and suggest how to select two
surface gravity wave packets in order to mimic some key aspects of Hawking
radiation from the horizon of non-rotating black holes. Our proposed setup,
unlike the scattering problem conventionally studied, constitutes of a constant
mean flow over a flat bathymetry, in which the two wave packets possess the
same amount of wave action but equal and opposite (sign) amount of energy,
thereby mimicking virtual particles created out of near horizon vacuum
fluctuations. Attention is given to the physical mechanism relating to the
signs of the wave action and energy norm with the wave's intrinsic and total
phase speeds. We construct narrow wave packets of equal wave action, the one
with positive energy and group speed propagates against the mean flow and
escapes from the black hole as Hawking radiation, while the other with negative
energy and group speed is drifted by the mean flow and falls into it. Hawking's
prediction of low frequency mode amplification is satisfied in our minimal
model by construction. We find that the centroid wavenumbers and surface
elevation amplitudes of the wave packets are related by simple analytical
expressions.
