Interacting with a CB Radio will help you finish a Legendary quest in Fortnite Chapter 2 Season 7.
Appearing during Week 5, and following on getting orders from a payphone this has you find a CB Radio within Believer Beach.
This challenge is also a useful way to get abducted by the mothership - which tends to happen more often than not in the Believer Beach area.
This article explains where to find the CB Radio location - alternatively, you can watch the following video to see footage of the challenge being completed:
CB Radio location: How to interact with a CB Radio explained
The CB Radio can be found on Believer Beach, the named location in the north-west of the map.
Specifically, you'll want to go to the west side of the beach. This is a little different to what the challenge screen suggests - which points it closer to the centre of the beach than where it is.
You know you are in the right location when there are some picnic tables and a campfire, with the CB Radio itself glowing blue.
Stand next to the CB Radio, then interact with the prompt to tune in and complete the challenge.
Once you've done that - it's time to take on the next challenge, place Welcome Gifts in Holly Hatchery.