yes, thank you, it's perfectly working!
...and this is my final code snipped for any future reference
thank you again for the support
Code:
'del old recs in the table
CurrentDb.Execute "DELETE * FROM data_ok"
'def start and end date
'#m/d/y
start_date = #3/27/2014 1:00:00 PM#
end_date = #4/10/2014 3:00:00 PM#
'def n cycles
'upper end open
n_hour = DateDiff("h", DateAdd("h", 1, start_date), end_date)
'upper end close
'n_hour = DateDiff("h", start_date, end_date)
For i = 0 To n_hour
CurrentDb.Execute "INSERT INTO data_ok (data) VALUES ('" & DateAdd("h", i, start_date) & "');"
Next