Burnley Comms tower is located in the east part of the district. You want to approach the building with the tower on it from the south. There is a window close to the top of the building. You will also notice that you can use your remote claw gadget in between the window and next door building. Do this and zipline through the window. There will be a fake comm station inside you can decipher, but Enigma tells you things won’t be that easy this time. If you look up you will se a vent grate you can pull on with your batclaw. This is where the bug happens. If you can enter the vent you will climb up on top of the building and disable the real jamming device. Here are some screenshot showing the first part.
Now, if you got stuck, you might be in the room with locked windows and can’t get out. Fast travel to the nearest drop point and come back to Burnley tower. The video bellow, posted by Steam user Kein Zantezuken in this thread, shows a bug you can exploit to jump over the fences and land on the rooftop and hack the jamming device. This will unlock the tower. It took a few tries, but it’s doable. If you are playing on the PC some people say that you want to turn off Physx in the game options for this to work, and others say to turn it on. Just try a few times and than change the physx setting just in case.