NOAA

NOAA Tone Detection

A special RX CTCSS tone value of 105.0 can be assigned to a channel to enable NOAA alert-style tone detection.

When this tone is configured:

• The channel’s squelch remains closed until a 1050 Hz tone is detected on the received signal
• Once detected, the squelch opens and remains open
• The squelch will close again when:
  • The signal is lost, or
  • The user manually intervenes

When the channel is tuned to a designated NOAA weather frequency, this configuration effectively enables NOAA alert monitoring.

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Visual Indicator

When NOAA Tone Detection is active, a raincloud icon is displayed on the VFO.

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Detection Latency

The radio requires approximately 250 milliseconds to detect the presence of a tone.

Because NOAA frequencies typically transmit a continuous carrier:

• The radio cannot immediately reject the signal
• It must wait the full detection period to determine whether the tone is present

As a result, when monitoring NOAA frequencies, particularly while Multiwatch is enabled, the radio may feel slightly less responsive.

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Configuration

See:
Radio → Main Menu → RX CTCSS