We have extended the observations in the far-infrared laser magnetic resonance spectrum of the SH radical in its ground 2? state to cover the first three rotational transitions in the 2?3/2 component. Signals were seen from all naturally occurring isotopes of sulfur except the least abundant, 36S (0.02%). The measurements have been analyzed, together with selected data from previous work, to determine an improved set of molecular parameters for 32SH in its ground state. The implications of these parameters are discussed. The magnetic and electric nuclear hyperfine parameters for 33SH are significantly improved over previous work. The frequencies of rotational transitions in 32SH in the absence of a magnetic field are calculated from the parameter set to aid in the detection of this radical in astrophysical sources.