The MFJ-1040C lets you copy weak signals. It rejects out-of-band signals and images. It covers 1.8 - 54 MHz with up to 20 dB gain. It has gain control. It uses a cascode FET/bipolar transistor for low noise, high gain. 20 dB attenuator. Connect 2 antennas and 2 receivers. It uses SO-239 connectors. Automatic bypass with transmitting to 125 Watts. Jack for push-to-talk. 9-18 VDC or use the MFJ-1312D power adapter.