NEC-Win Plus+
Equations
Type an equation directly into a cell.

After you click ENTER the cell will hold the value of the equation.

Using variables!
You define variables and formulas on the Equations page.
By default the start frequency and wavelength from the toolbar is tracked for easy use.

Enter a value and comment in the A variable cell.

Now go back to the Wires page and click on a cell and type
=A
and hit Enter. When the cell is highlighted you can read the
forumula for the cell in the text box above the spreadsheet. You can
also see that wire one coordinate x1 is actually spreadsheet cell
B1.

Using the scratchpad
You can use the scratchpad to write larger formulas.
Enter the following in the scratchpad:

Now you can reference the scratchpad using column-row indexing:

You can even reference the scratchpad back on the Wires page. To
do this you type =Equations! and then the column-row index.
e.g. =Equations!E5

You can reference the Wires page in the Equations page:
