- Availability: Steam only; must complete the entire game first and play each chamber again. Completing a chamber or chapter does not enable the radios to be available.
The newest achievement, added in March 1, 2010 to Steam only, requires the player to find one (or more in some of the larger stages) radio(s) in each level and bring each to a specific point. A radio will have a red light on the front if it hasn't been brought to the correct location. The music will change to static as you approach the correct location, and then to a hidden signal when you have arrived, at which point the light will turn green. The achievement for an individual radio persists across saved games, though the light will change back to red. Since this achievement is only available after you have played through the game once, during the first play through only the initial radio exists and its blue light and signal will not change if brought to its achievement location.
- Hidden signal
The hidden signal that is picked up after bringing a radio to its achievement location is either Morse code or a slow-scan television (SSTV) signal, which can be decoded into a picture with free SSTV decoding software (like RX-SSTV). To get full benefit out of them, you need to use sound recording software, or otherwise extract the audio files from the game.
|Chamber||Radio initial location||Achievement location|
|Chamber 00||In the relaxation vault.||The button room, just over the button.|
|Chamber 01||On the camera to the right of the entrance. It can be grabbed before dropping down.||The exit, just before the door to the emancipation grid.|
|Chamber 02||On the wall containing the hole through which the portal gun fires. One way to reach this is to, while near the orange portal, shoot a blue portal at the ceiling just above the radio.||Where the portal gun was initially located.|
|Chamber 03||On the camera near the exit. Knock the camera and radio down by shooting the wall with a portal.||By the ceiling above the second pier and the wall facing the orange portal, at the corner.|
|Chamber 04||Released with the storage cube.||The entrance.|
|Chamber 05||Behind the door opened by two buttons. Shoot a portal under it before stepping through the door.||The pit previously containing a cube.|
|Chamber 06||Above the pellet launcher. Shoot a portal near the launcher and grab it through the portal.||The exit lift.|
|Chamber 07||Under the entrance platform, behind the stairs.||The exit.|
|Chamber 08||Below the moving platform's initial position.||Near the chamber number.|
|Chamber 09||Within the small opening between the two sections. Methods of retrieving are described in the walkthrough for this chamber.||The exit.|
|Chamber 10||In the third section, on a tiny ledge on the left. To get it, proceed with the test until you are on the other side of the gap. At this point, either set a portal on the lower right panel and fall through the orange portal, or stand as close as you can to the radio and jump towards it. In either method, pressrepeatedly for the best chance of grabbing the radio.||The orange portal.|
|Chamber 11||In front of the door between the main and final areas. To reach it, shoot a portal near the radio, and grab it by standing within the portal.||Where you collected the orange portal gun.|
|Chamber 12||On the middle support of the panels that are extended furthest. To reach it, place portals on the angled platform and the bottom, then fall through starting from the first level.||Directly under the angled panel.|
|Chamber 13||On the right-hand side of the main room. Grab it from the moving platform.||The window above the button of the initial room.|
|Chamber 14||Between the button and the door it powers, on the right wall. Use momentum and a portal below it to grab the radio.||The stationary platform in the middle of the sludge.|
|Chamber 15||Hidden up behind the extended panel you use to launch yourself through the field. Place a portal on the wall next to and behind the panel, and you can grab it.||The entrance.|
|In the final room, within the pellet receiver container. Press the two buttons, and then place portals in a way that allows you to jump into the enclosed area (two portals on the ground, one being in front of the container). GLaDOS will release you from the area.
|Chamber 16||In the side room with multiple storage cubes.||In the secret area behind the extended panel, next to all the scribblings.|
|Chamber 17||Under the third lift leading to the exit.||The incinerator.|
|Chamber 18||In the side room after the first gap.||The signal point can be reached by firing a portal on the ceiling directly above the two dot symbol on the floor of the next platform, and holding the radio through a second portal on the floor (while crouching). You can also just drop it through, or fall through yourself while holding it.|
|In the room with all the turrets on platforms. It is on top of the box which contains the pellet receiver. Use a floor portal fling to get on the box.||The back of the area with a small button, below the cube dispenser area.|
|At the bottom of the pit to the left in the final room.||In the middle of the exit platform.|
|Chamber 19||In the giant incinerator, on the left (right from the balcony). Set a portal just above it, then create another portal, and go through half of it to catch the radio without being burned.||In the center of the side office, soon after the two big fans.|
|Escape 00||Just after the load screen, you will find some stairs to the right. Under the stairs the way is blocked, but portal through the fence and crawl into the vent to a small area containing supplies and the radio.||The center and back of the top of the platform just above the two vertical pistons that you use to get through a ceiling portal.|
|Escape 01||After being ambushed by three turrets, you will find the radio near the broken sentry.||In the next room, after knocking down the turret, enter the alcove containing supplies.|
|Escape 02||When you enter the turret arena, the radio is in the lower section, on the opposite side of where you entered the arena.||When you exit and reach the two turrets that are dropped from the ceiling, fling up to the next level and bring the radio near the green generators.|