A thank you note.
 

Thanks to everyone for your input about waves, and
other questions. It's not practical to write thank you notes
all the time, but I do want to let you folks know I appreciate
your help, and people sharing their knowledge.

On the wave topic, I'm going to post it to some physics
and space related groups, and will make a post to these
groups if I learn anything interesting.

Thanks again!
David