When you turn on the receiver for the first time, the module on the right side will have four numbers entered and the light will be green. These numbers are the broadcast frequency for the Radio Station. I recommend writing these numbers down somewhere, maybe on a sign in game, although they should appear in your journal as well. On the radar part of the receiver you may see some green dots, which represent the large islands in your surrounding area, but you will also see a blue marker which shows the story location based on the broadcast frequency number that you have entered.
Sailing in the direction of the blue marker will take you towards the Radio Station. You can turn off the receiver to save battery power and you can replace the battery without the location of the Radio Station changing. However, I recommend checking the receiver regularly to make sure you are still going the right way. When you get to be about 300 blocks away from the Radio Station you will begin to see it faintly.
Climbing up to the top-most room of the Radio Station and standing in front of the whiteboard will grant you the achievement.