Selected range of cells via VBA doesn't work - excel

Question

EDITED
I would like to ask you for help & revision of my VBA code as I am new to VBA.
I have pivot table with 3 columns. Via slicer I choose the items I want to add in new data table, each item must be added 3 times - therefore in the code I used loop 3 times.
The VBA works perfectly when 2 or more items are chosen.
However, when only single item is selected, the VBA crashes because the "selected copied range" does not have the same size as "pasted range" size. Basically, it selects all cells from column "F2:H2" until the end of spreadsheet.
Sub Copy()
Dim i
For i = 1 To 3
StartRange = "F2:H2"
EndRange = "F2:H2"
Set a = Range(StartRange, Range(StartRange).End(xlDown))
Set b = Range(EndRange, Range(EndRange).End(xlDown))
Union(a, b).Select
Selection.Copy
lastrow = ActiveSheet.Cells(Rows.Count, "T").End(xlUp).Row + 1
Cells(lastrow, "T").Select
Selection.PasteSpecial Paste:=xlPasteValues, Operation:=xlNone, SkipBlanks:=False, Transpose:=False
Next i
End Sub
How to modify the code, if only single item is selected, it will copy the cells in new data table as well?
I can provide a test file for reference.

Answer 1

Use .End(xlDown) from the header row.
Option Explicit
Sub Copy()
Dim ws As Worksheet, rng As Range
Dim i As Long, lastrow As Long
Set ws = ThisWorkbook.ActiveSheet
Set rng = ws.Range("F2", ws.Range("H1").End(xlDown))
For i = 1 To 3
lastrow = ws.Cells(Rows.Count, "T").End(xlUp).Row + 1
rng.Copy
ws.Cells(lastrow, "T").PasteSpecial Paste:=xlPasteValues, Operation:=xlNone, SkipBlanks:=False, Transpose:=False
Next i
End Sub
or to copy single rows
Sub Copy2()
Const REPEAT = 3
Dim ws As Worksheet, rng As Range
Dim row As Range, lastrow As Long
Set ws = ThisWorkbook.ActiveSheet
Set rng = ws.Range("F2", ws.Range("H1").End(xlDown))
lastrow = ws.Cells(Rows.Count, "T").End(xlUp).row + 1
For Each row In rng.Rows
If Not row.Hidden Then
ws.Cells(lastrow, "T").Resize(REPEAT, row.Columns.Count).Value = row.Value
lastrow = lastrow + REPEAT
End If
Next
End Sub