What device increases the transmitted output power from a transceiver?

To boost the radio frequency (RF) signal coming out of your transceiver before it reaches the antenna, you use an RF power amplifier. These devices take a lower power signal (like 5 or 100 watts) and amplify it to a much higher level (like 500 or 1500 watts). The other options serve completely different purposes in electronics. A voltage divider reduces voltage, and an impedance network (like an antenna tuner) matches impedances between the radio and antenna to transfer power efficiently, but it cannot magically add power to the signal.