Here is the full list of all 23 Alt-Frequencies achievements. It takes around 1-2 hours to unlock all of the achievements on Windows.
Complete the tutorial.
Ask A. None a relevant (???) question.
Suggest a cure for Michelle's flu.
Complete chapter one.
Have Sadie be broadcasted on another frequency.
Complete chapter two.
You sent the RMB-1 scoop to Talk radio.
You sent the RMB-1 scoop to Fresh FM.
You sent the RMB-1 scoop to News One.
Disturb Fred with the voice of his manager Margot.
Shame Ennis with his past.
Complete chapter three.
You sent Kaya's list.
You sent Jenni's list.
Learn about the Landing Plane.
Complete chapter four part one.
Confuse Ennis with the nature of your offer.
Complete chapter four part two.
Reveal the new voice of resistance.
Spoil Ennis' new song.
You stayed in the time loop.
You left the time loop.
Complete chapter five.