Continuous Tone-Coded Squelch System (CTCSS)

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Continuous Tone-Coded Squelch System (CTCSS)
CTCSS vce.jpg
Frequencies 30 MHz,800 MHz
Frequency Range 30 MHz - 800 MHz
Mode NFM
Modulation CW
ACF
Emission Designator
Bandwidth 5 kHz,12.5 kHz,30 kHz
Location Worldwide
Short Description CTCSS, also known as Private Line and Channel Guard, is a low continuous tone transmitted on NFM voice transmissions that is used to squelch and manage transmissions on a given frequency.
I/Q Raw Recording Download file
Audio Sample

Continuous Tone-Coded Squelch System (CTCSS) is a low continuous tone transmitted on NFMNarrowband Frequency Modulation voice transmissions that is used to squelch and manage transmissions on a given frequency. This is also known as Private Line® (PL) by Motorola, Channel Guard® (CG) by General Electric and generically as tone squelch. The CTCSS system sounds like a low hum to listeners.

CTCSS is used in many analog FMFrequency Modulation public safety radios. They have a characteristic look on the waterfall, as continuous lines emanating around the center frequency carrier.


Mode Samples[edit]

151.4 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz). CTCSS 173.8 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz). CTCSS 186.2 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz). CTCSS
151.4Hz ctcss.jpg
173.8Hz ctcss.jpg
CTCSS 186.2.png

CTCSS Full Range
CTCSS.jpg
Table of tones, source from RadioScanner.com. Note: 150.0 is the standard tone used by military radios in the 30-88 MHzMegaHertz (MHz) 10^6 Hz band.

Decoding Software[edit]

Video Examples[edit]


Additional Links[edit]

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