User Manual

WiNRADiO G3XX VHF/UHF Receiver
Squelch Control
The Squelch control can be used to mute the receiver when no signal is
being received. Without a signal, all you will usually hear is noise. Squelch is
provided to cut out the noise until a station is found, making the receiver more
comfortable to use.
There are two types of squelch in the G3XX receiver: Signal level squelch
(selected by the Level button) and Audio noise squelch (selected by the
Noise button).
The Level squelch setting controls the signal level (in dBm) at which muting
occurs. Muting will occur when the signal level drops below the preset squelch
value. When a signal of a higher level returns, the sound will be restored
immediately.
To adjust the squelch control, first tune to an unoccupied frequency that
produces only noise. Increase the squelch until the receiver is muted. You will
see the red-colored segment of the S-meter growing until it gets higher than
the current S-meter value. At that moment the receiver will be muted. Add a
few dB extra (to allow a margin for background noise fluctuation on the band).
Now when you tune to an occupied frequency, if its signal strength is higher
than the squelch level, the receiver will be unmuted.
The Noise setting makes it possible to mute the receiver depending on the
contents of noise in the demodulated signal, and is typically only used in the
FM mode. As the FM demodulator produces strong noise when no signal si
being received, a special filter is used to detect such noise and its level
compared to the specified value. When the noise exceeds this specified value,
the audio is muted. The Noise value is entered as a percentage of white noise:
Zero value signifies a clean signal, while 100% corresponds to pure white
noise (no useful signal). The actual noise level is displayed in the demodulator
panel, alongside the AF Squelch control:
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