VBA PivotTable variable range

I want to automate the production of charts I produce on a regular basis, but although I have a standard txt download & pull it in OK, it varies as to the number of records each week, and the Pivot Table DataSource Property doesn’t seem to want to accept a named range or any of the UsedRange, CurrentRange type entries. Can someone tell me how I can work around this so that each week’s charts will run off the full download, but without throwing blank records into the equation?

Thanks, Crystal