  A 2.5D numerical model of magnetoacoustic-Alfv\'en linear mode conversions in
the partially ionised low solar atmosphere induced by the Hall effect is
surveyed, varying magnetic field strength and inclination, and wave frequency
and horizontal wave number. It is found that only the magnetic component of
wave energy is subject to Hall-mediated conversions to Alfv\'en wave-energy via
a process of polarisation rotation. This strongly boosts direct mode conversion
between slow magneto\-acoustic and Alfv\'en waves in the quiet low
chromosphere, even at mHz frequencies. However, fast waves there, which are
predominantly acoustic in nature, are only subject to Hall- induced conversion
via an indirect two-step process: (i) a geometry-induced fast-slow
transformation near the Alfv\'en-acoustic equipartition height $z_{\rm eq}$;
and (ii) Hall-rotation of the fast wave in $z>z_{\rm eq}$. Thus, for the
two-stage process to yield upgoing Alfv\'en waves, $z_{\rm eq}$ must lie below
or within the Hall-effective window $0\lesssim z\lesssim700$ km. Magnetic field
strengths over 100 G are required to achieve this. Since the potency of this
Hall effect varies inversely with the field strength but directly with the wave
frequency, only frequencies above about 100 mHz are significantly affected by
the two-stage process. Increasing magnetic field inclination $\theta$ generally
strengthens the Hall convertibility, but the horizontal wavenumber $k_x$ has
little effect. The direct and indirect Hall mechanisms both have implications
for the ability of MHD waves excited at the photosphere to reach the upper
chromosphere, and by implication the corona.
