I have found the trick to prevent 0's from showing in a chart when the data
is blank:

If(H2="",NA(),H2/F2)

However, the chart line extrapolates from the previous data point to the
next datapoint instead of showing a gap. I've looked at Tools-Options-Chart
and the Active Chart - Plot Empty Cells as "Not Plotted (leave gaps)" is
selected.

The data is being charted on a secondary Y axis if this makes a difference.
Please help. I need to have gaps.