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2 NM Fog Signal

  • 2 nautical miles range
  • Sound pressure level 133.2 dB at one meter
  • Output frequency 664 Hz
  • Connection to the NAi bus via an external bus coupler
  • Power supply and communication via standard NAi bus interface
  • Suitable for series connection of multiple NAi components

The SFH6 is a compact and lightweight 2 nautical miles fog signal. It satisfies the requirements for sound signals of the IALA recommendations R0109 The Calculation of the Range of a Sound Signal and E-109. The fog signal is equipped with six compression drivers and power amplifier.

The fog signal will be activated and deactivated on demand, according to the data of the visibility meter which is connected to the NAi bus as well. It is emitting a 360-degree beam of sound in the horizontal plane with an acoustical range of 2 nautical miles.

The fog signal is connected to the NAi bus by means of an external BUS coupler. This allows it to be supplied with electric power via the NAi bus and to be controlled via the central NAi Controller so that status values are available to the central SCADA system.


Technical Data
Dimensions (diameter x height)323 mm × 1301 mm
Weight67 kg
MaterialCorrosion resistant aluminium housing
Housing colourYellow
Signal output133.2 db
Output frequency664 Hz
Nominal range2 nautical miles
Operating CodeMorse U 30 s sound signal
(standard, others on request)
Certification2 nm fog signal according to IALA Recommendations E-109. ISVR Consulting, University of Southampton, UK
Operating voltage24 V DC nominal
Power consumption100 W
Environmental temperature-40°C to +55 °C
Degree of protection (acc. to IEC 60529)IP66
Protection classClass III