There is a relationship between SR, TPK and speed:
this can be re-arranged to:
and:
TPK is specified on the page. So, if have boxes for SR and Speed, when one box is left empty, we can calculate it. We probably need a Calculate button for this. If both SR and Speed are populated, show a warning. If one is populated, calculate the other.
This could be called Speed Calculator and be added to the bottom of the harmonic calculator.

There is a relationship between SR, TPK and speed:
this can be re-arranged to:
and:
TPK is specified on the page. So, if have boxes for SR and Speed, when one box is left empty, we can calculate it. We probably need a
Calculatebutton for this. If both SR and Speed are populated, show a warning. If one is populated, calculate the other.This could be called
Speed Calculatorand be added to the bottom of theharmonic calculator.