I've made something like that b4... Just looked in a book, and stuck all the electronic pieces together (I ripped the pieces out of old phones/tape playesr/etc) then I could broadcast AM radio for 10feet
And about the pirate radio station... Just get a laptop, some external battries (enough for 24 hours) and the card. Bury it somewhere with a small hole + fan to ventilate the laptop + looooooong uninsulated wire wrapped around the antenna that is run around a circle with a radius of 20feet, then connected to a huge metal thingy (sign pole for example) so the signals can get far
Heheheheheh that would be funny