If I remember right you have to get it from Mr. Fugi.
Radio Station in Lavander town
You walk through the door. There is nothing interesting in there except for a man who will give the expansion card for your radio.
You will receive it from a person in the Lavender Town Radio Tower.
In Lavender Town, Pokemon Tower If you got the radio card from Goldenrod then I beleive somebody on the ground floor will give you the expansion
Kanto radio broadcast. Top of the radio circle in kanto.
the kanto radio staion is in lavander town
You find the EXPN card in Kanto, Lavender Town at the Radio Tower. I didn't find it there and I need it BADLY!!!Well this is me again I have the Expansion Card, but it won't show the Kanto Radio Station Songs..PLEASE HELP!!! O.K I needed to change it to the Pokemon League Dis-sign on your Poke Gear!!
Do you mean the Power Plant? Are you looking for the way to activate your radio in Kanto? That can be done at the Power Plant.
you go to the Kanto radio tower in lavender town
First you have to power up the Kanto power plant and then go to the Kanto radio tower talk to the man in the buisness suit and he will give you the Kanto radio card. So there! I hoped this helped!
In heartgold and soulsilver it is a new radio channel located at the top of the radio. you can only hear it in Kanto you will need to get the Expansion card from the Lavender Town Radio Manger, after you solve Kanto's power problem. With it you can wake the sleeping, roadblocking, caveblocking snorlax. I played Gold,Silver, & Crystal versions awhile back, I think it was the same way.
The Kanto radio tower is in Lavender Town.