If you restore antique AM radios, you may have noticed that there is little or no decent music available on AM broadcast. In this video, I how how to build a very simple AM transmitter that lets you play MP3 through an antique radio.
Matching transformer: http://www.digikey.com/product-search/en?keywords=MT4153-ND
Xtal oscillator: http://www.digikey.com/product-detail/en/cts-frequency-controls/MXO45-3C-1M0000/CTX775-ND/1801890
MP3 player: http://www.ebay.com/itm/New-Black-Mini-Remote-Control-USB-SD-FM-MP3-Audio-Player-Module-DC5V-12V-DIY-/162193192705