You walked over the cable holding the antenna, right? Now, to jump speak to Argus. After he counts two you should have the Jump arrow visible for a brief moment. That is your cue to jump.
Unlike normal walkthroughs, in Nice Game Hints you can select just the puzzle you want hints for. Here are listed the puzzles for "How to get to the transmitter" in Goodbye Deponia. The guide you choose only contains information about that puzzle, reducing possible spoilers for other puzzles.