diff --git a/mao_merge_45m/power_meter.py b/mao_merge_45m/power_meter.py
index 88e8db8..5e41ab9 100644
--- a/mao_merge_45m/power_meter.py
+++ b/mao_merge_45m/power_meter.py
@@ -47,7 +47,7 @@ def convert(
 ) -> Path:
     """Convert a raw log file(s) to a formatted Zarr file.
 
-    This function will make a one-dimensional antenna log outputs
+    This function will make a one-dimensional power meter log outputs
     with time metadata derived from the raw log file.
 
     Args:
@@ -116,6 +116,7 @@ def convert(
         df_ = df_.drop(columns=["time", "num", "num_max", "s"])
         df = pd.concat([df, df_])
 
+    df.sort_index(inplace=True)
     # write DataFrame(s) to the Zarr file
     ds = PowerMeter.new(df.total_power)
     ds = ds.assign_coords(time=ds.time - JST_HOURS)