Marantz AV7703 Owner's Manual page 346

Important: External Antennas
The removable external antennas are required for both
Bluetooth and Wireless network connectivity. Please make
sure to connect the antennas before attempting to use the
Bluetooth or Wi-Fi features of the AV7703.
3
n Connecting the external antennas for
Bluetooth/Wireless connectivity
For each of the two antennas:
Place the antenna evenly over the antenna terminal
located at the upper left or right corner of the rear panel.
Turn the antenna clockwise until it is fully connected. Do
not over tighten.
Rotate the antenna upwards for the best possible reception.