In article 76070442-c8f1-4043-8437-d9e3cbaad885
@y5g2000hsf.googlegroups.com, says...

Note - There is a 2 1/2 Second Round-Trip Lunar Propagation Delay.
http://www.setileague.org/eme/emepix3.htm

EP .= = = = _ _ _ _ _ _ 5s
LR ._ _ _ _ _ -- -- -- -- _ 5s

"." Start of the Time Sync for 5 Second Signal Cycle
"=" Earth Pluse Time
"_" Non-Signal Time
"--" Lunar Reflection Time

~ RHF
.

I don't think that is quite correct. If the pulse were only a
millisecond long, 0 to .001 on the time line, you would receive the echo
at between 2.500 and 2.501 seconds on the time line. If you think of a
two second pulse as only a series of millisecond pulses, the first pulse
(or the beginning of a two second pulse) would be hitting the moon after
1.25 seconds and starting on its way back before the last millisecond
pulse (or the end of the 2 second pulse) even left.

I think you are treating the pulse as a single discrete object that
actually doesn't leave until the pulse is complete, like bouncing a ball
off the wall. I don't think that is the case.

I think it is more like a long train (2 seconds long) on a short U
shaped track (1.25 seconds on each leg). The engine coming back will
pass the caboose still on its way to the end of the U. The engine will
reach the end of the return leg 2.5 seconds after it left. The caboose
will also reach the end of the return leg 2.5 seconds after it left, but
it will be 4.5 seconds after the engine left making the total time for
the train (2 second pulse) to make the trip (one cycle) 4.5 seconds.