On Wed, 16 Jan 2008 10:42:32 -0500, "Jim"
wrote:

I know how to measure amplitude or time with a scope. I just can't figure
out how to measure distance.

You don't measure distance on the scope, it measures time. Given the
speed of the wave, typically 300,000,000 meters/sec, it is easy to
calculate distance, e.g., a 1 microsecond wave equals 300 meters
wavelength.