On this page of our game guide to Batman: Arkham Knight we have provided a description that depicts how to use the Panessa Studio antenna. You have to do so in order to find Scarecrow.
Leave the Clock Tower through the hatch in the roof. Listen to a conversation with Gordon and head to Panessa Studios. When you reach it, investigate one of the top shelves and try to use the Remote Hacking Device. You will fail because of the generator problem. Wait until Lucius Fox contacts you and head to the airdrop area. When you're there, summon the Batmobile and park in the area marked by the game. Soon, a Winch will be attached to your vehicle.
Point the Batmobile towards the train station neon and switch to Battle Mode. Now use the Winch - you have to catch the neon and move the analog stick down or hold the down directional key. This will remove the obstacle (it will take you a few seconds to detach the neon from the building). Head straight and use the booster to reach the roof of the nearby building.
There is another interactive object on the right. Use the Winch on it (after entering the Battle Mode). Raise the platform, head towards it and use the booster to make a long jump with the Batmobile. Now you muse carefully drive across the fragments of the roof. You can stay in the Pursuit Mode or use Battle Mode and "slide".
Soon, you will reach the last part of the roof. Locate the third interactive object and use the Winch. This time, you will not be pulling the object to you, but you will pull yourself towards the object. Allow the Batmobile to turn 90 degrees up (so it's in a vertical position) and when you're on another roof, detach the Winch.
With the Batmobile, reach the generator near the antenna and use the Winch one again. You have to charge the generator using the acceleration pedal. Observe the revolution gauge in the bottom-right corner. The arrow has to constantly stay in the orange area. Fortunately, you can retry if you fail. After activating the first antenna, listen to a conversation with Oracle and Robin.