macro to create charts in worksheets with arbitrary names

I'm trying to write a macro to create and modify charts in
spreadsheets with many worksheets. The problem I cannot
solve is that the macro uses the current worksheet name
(here Channel_1) in the code, as in the following short
example:

' Keyboard Shortcut: Ctrl+a
'
Range("G2:H11").Select
Charts.Add
ActiveChart.ChartType = xlXYScatterLinesNoMarkers
ActiveChart.SetSourceData Source:=Sheets
("Channel_1").Range("G2:H11")
ActiveChart.Location Whe=xlLocationAsObject,
Name:="Channel_1"
End Sub

which prevents it from running in a different worksheet. I
tried invented statements like .ActiveWorksheet. etc, but
it didn't work...

How to make the worksheet name generic to the macro
without having to rename the worksheet before the macro is
run?

z.entropic