Brian excited about finding a transmitter because he thought that the transmitter is broke.
Step-by-step explanation:
Brian seen twice using the transmitter in the chapter and the first time he finds it, the signals which were send from the transmitter to the operator were blurry and thought that the transmitter is broke.
The result operator could not help Brian for landing the plane and because of this reason Brian did not get very happy after seeing or finding a transmitter again when he saw it which was the emergency transmitter and it was a little tough to use also for sending the signals to the operator.