The power from the reverse path is padded down (attenuated) by the same amount. This means that the system is capable of measuring reflected power up to 0dB. This may not be necessary if the system is designed to shut down when the reflection coefficient degrades below a certain minimum (e.g. 10dB), but it is permissible because the detector has so much dynamic range. When the HPA is transmitting +20dBm, the reverse path detector will see an input power of –60dBm if the antenna has a return loss of 20dB.