UVMFS affects UV plots, allowing the user to show the effect of using multi-frequency synthesis. The first argument is the number of tracks to plot per baseline. The default is to plot one with UV in km. The second argument is the ratio of the highest to the lowest MFS frequency. The UV values will be in km the middle of the frequency range.
This option could have been implemented by paying attention to the frequencies in the setup file, and that option should be added some day. But that requires either fully specified setup files, or freq.dat entries for all stations. When SCHED is being used for configuration studies, this is an undue burden.
Note that this is also used for the UV coverage based quality measures used for configuration studies.