Furuno FS-1575 FS-2575 FS-5075 User Manual

2.  SSB RADIOTELEPHONE

(High) 

→ [NR1] (Low) → Off). When the noise reduction function is active, 

 or 

 

is displayed on the RT screen.

The notch filter removes mixed CW (continuous wave) or beat signal interference. 
Press the 8/NF key on the RT screen to turn the notch filter on and off alternately. 
When the notch filter function is active, 

 is displayed on the RT screen.

The squelch mutes the audio output in the absence of an incoming signal. Press the 
3/SQ key on the RT screen to turn the squelch on and off alternately. When radio noise 
is too jarring during stand-by condition, it can be muted by activating the squelch. 
When the squelch function is active, 

 is displayed on the RT screen.

To adjust the squelch frequency, see section 6.4.

The attenuator reduces total gain and prevents saturation. Push the RF GAIN/PUSH 
TO ATT knob on the RT screen to turn the attenuator on and off alternately. When the 
attenuator function is active, 

 is displayed on the RT screen.

The [USER CH] menu provides for registration of user TX and RX channels, where 
permitted. For further details, contact your dealer. See section 6.2 for the procedure.