A City in Chains | Walkthrough Homefront: The Revolution Guide
For the first time, you will reach a yellow zone, Earlstone. This zone is governed by different rules than those of red zone. Above all, at the beginning try to sneak past the patrols, rather than fight with them. The enemy numbers will be much higher than in the red zone, while new reinforcements arrive constantly. With this mentality, you have to get to the marker shown on the map, and take over the derelict warehouse.
At the beginning, ignore every pedestrian needing help, and try to walk away from patrolling guards. After you reach your destination, you should see the view like on the screenshot. The area is patrolled by 2-3 soldiers, so move as close to the left side as possible and enter the restricted area. You will find a camera here, which monitors everything. You can destroy it so it won't detect you. You can also go under it and slide into the warehouse.
The KPA transmitter is on the first floor of the warehouse. Get upstairs and hack it to complete the task. You will receive 600$.