SAMPRATE is used to set the sample rate in million samples per second. Only one value is used for all baseband channels. This is usually, but not always, twice the baseband bandwidth specified with BBFILTER. Not used for Mark II.
If not specified, twice the maximum bandwidth will be used, if BBFILTER was specified.
Note that the SAMPRATE should not be less than 2 Mbps for the VLBA (may change with Mark5C). That is the minimum track bit rate for the old tape systems and for the Mark5A and the fan-in capability was never activated so lower sample rates cannot be recorded. The user will need to specify the SP: SAMPRATE in such cases because the defaulting doesn't deal with this restriction. It would be fixed, but the restriction will likely go away soon.