Billy Burpelson wrote:


What I -did- speculate on is that a *portion* of the echo (the
echo's leading edge) will be QRM'd *right as it leaves the moon*
(the first 0.75 seconds of the echo) by the trailing edge of the
incident wave (its last 0.75 seconds). Therefore, either a
shortened echo (due to full cancellation of the 'overlap', which is
unlikely) or an echo with a distorted or weakened leading edge
(more likely) will ultimately reach the earth, depending on how
much out-of-phase cancellation at the moon end of the circuit
occured.



Your error is assuming that echo is modified by the incident wave. The waves
pass by each other without interacting.

When you try to observe the waves, using any method, you get the sum of the
two signals. So anywhere they 'overlap' you will see interference. This is
superposition.

If you look at a point where there is no overlap, you only see one signal.
Then you observe no interference.