150.7375 NAC 293 is a possible repeater, possibly used by National Guard (reported elsewhere as a NG temporary repeater). It's only been heard a couple of times briefly in the Houston area (likely during tropo ducting) so it's probably used somewhere else. See if you can hear it in your city. Activity has been consistent with COVID-19 testing.
COVID-19 Houston area frequencies and talkgroups: COVID-19 - Scanner Frequencies and Talkgroups
COVID-19 Houston area frequencies and talkgroups: COVID-19 - Scanner Frequencies and Talkgroups