How exactly do shortwave relay stations work? Your customers may ask that.

Print out these webpages:

http://CBC.am/rci-bc.htm
http://CBC.am/rci-sask.htm
http://CBC.am/radio.htm


how exactly do shortwave radio's work? Can someone please direct me to
a website which explains the essential aspects behind this technology?

I feel bad because I work in an electronics store, and we do carry
shortwave radio's....although customers haven't really asked in-depth
questions about it as yet. I just want to prepare myself. Thanks.