[AtomicOrbital]

Essence of radio is very simple ... radio station broadcasts a high power RF signal into which some human listenable audio (your favorite singer's song) is mixed ... so the radio station propagates this RF signal modulated by the song being played ... across town at your house your radio synthesizes an RF signal identical to that broadcast from the radio station ... your radio amplifies the result of combining its local RF signal together with the received RF signal from the radio station ... this combining will add together both RF signals it will also subtract both ... when it subtracts ( wave interference ) the result is the difference between the radio station modulated RF signal and your radio RF signal (both at identical frequencies) which leaves you with just the song

[luyu_wu]

That's not what the article is about... Many people lack details on how antenna designs are optomized and the application of Faraday and Lenz's law in signal propogation. This is what the article addresses.