In his Ongoing History of New Music, the veteran CFNY/Q107 broadcaster offers a primer on radio frequencies.

Part 1: FM and how it differs around the world

Part 2: AM Spacing in North American and Europe

Part 3: What is "Medium Wave" and Shortwave?

Part 4: An explanation of DAB

For some here, there isn't anything entirely new, but it's certainly a concise and interesting read.