Use `xdpyinfo' (a standard X client that is provided as part of the X core distribution) to check several server parameters. (As with virtually all X clients, it doesn't matter which machine you find `xdpyinfo' on; it will query your server from wherever it is run.) `xdpyinfo' will report the version and release numbers of your server; you should have version 11, release 3 or later. It will also report the screen size in pixels and the resolution in pixels per inch. Take a minute to verify the screen resolution by direct measurement of the screen with a ruler. If the resolution reported by `xdpyinfo' is incorrect, WAVE will not be able to draw waveforms at properly calibrated scales. The sample X11 servers from MIT all support a `-dpi' option, which allows you to specify the correct screen resolution at the time the server is started; read the man page for X for details. (If your server does not support this feature, WAVE can be given a similar `-dpi' option.)
You can also double-check your display calibration using WAVE itself.
Run WAVE, enable the grid display, and set the display scales to
their default values (25 mm/sec, 10 mm/mV). (Click on
to pop up the controls for the grid and the display
scales; remember that any adjustments you make become effective only
after you click on 
within the View window.) The
grid intervals should measure exactly 5 mm in each direction. If they
are too small, use a larger value for the `-dpi' specification; if the
grid lines are more than 5 mm apart, decrease the `-dpi' values.