The NOAA N43 P-3 Radar Data - aircraft relative [NOAA/AOML/HRD] data files appear to be in the HRD lower fuselage data format, which is a per-sweep format, but is *not* DORADE sweep file format; the files each contain a 240x240 grid of reflectivity data for a sweep. The HRD format is described here:

Soloii only works on DORADE format data that follow a particular naming convention.