What's a "high-frequency radio signal" and how do baby dragons emit it?

[elementofloyalty]

Character(s): Rainbow Dash and Jack Spicer
Location: Engineering Classroom
Rating: PG
Open/Closed/Finished: Closed
Summary: Equestria does NOT have the sort of communications methods that class is talking about.

( 'Mailpony' doesn't seem to be an option here either... )