Step 1: Open the front case by removing the 4 screws from the back of the radio.

Step 2: Unplug the antenna cable shown gently from circuit board

Step 3: Pry out antenna gently using a screw driver

Step 4: Install the new antenna. Gently hammer the brass base of the antenna until it sits firmly

Step 5: Reverse the previous steps to reinstall the radio.
Bend the root of the antenna left, right, front and back once each direction slowly, at about 80 degrees. This operation is to prevent the snap of antenna cover under impact.

Done!