uataq.filesystem.groupspaces.lin.LGR_UGGA_File.utc_clock_switch

LGR_UGGA_File.utc_clock_switch = (Timestamp('2015-12-29 00:00:00'), Timestamp('2015-12-30 00:00:00'))

The day the analyzers’ clocks were switched from Mountain time to UTC, as (start, stop). Raw times before it are Mountain time, and the rows of the day itself are dropped (see parse).