Sony AVD-C700ES - Manuel (Page 18)

18 US
If you have poor FM reception
Use a 75-ohms coaxial cable (not supplied) to connect the receiver to an outdoor FM antenna as shown below.
Note
If you connect the receiver to an outdoor antenna, ground it to protect against lightning. To prevent a gas explosion,
do not connect the earth wire to a gas pipe.
FM
75
COAXIAL
AM
ANTENNA
To earth
Outdoor FM antenna
Receiver
Earth wire
(not supplied)