• Underwater Acoustic Beacon for aerospace, maritime & military markets
  • Provides a minimum of 90 days of uninterrupted operation once activated, at an acoustic output of 160 dB operating frequency of 37.5 kHz
  • 4" Length Beacon
  • Designed to provide outstanding performance and reliability
  • Capable of operation at depths of up to 20,000 feet
  • Detectable at a range of 2000 to 4000 yards based on environmental factors
  • Sustained pressure up to 8700 psi
  • Water switch actuation initiates beacon operation upon immersion in either fresh or salt water
  • Tested to meet, or exceed, all requirements of FAA TSO-C121b/SAE 8045A
  • Additionally tested for batteries as per TSO-142a

Theory of Operation

  • The DK120-90 is a battery operated underwater acoustic pulse generator (beacon/pinger) that is activated when the water switch is immersed in either fresh or salt water
  • The water switch is part of a low current triggering circuit, which when closed will initiate normal pulsing of the beacon oscillator circuit. The output voltage of the oscillator is coupled to the Piezo-ceramic transducer ring
  • The resultant mechanical motion is transmitted to the metal case of the beacon, which in turn radiates acoustic energy into the surrounding water at 37.5 kHz. The pulse generated are approximately 10 ms in duration, and occur about once per 1 second
  • The beacon will operate for a minimum of 90 days after being immersed in the water. The beacon will withstand depths to 20,000 feet. It can be detected at a range of 2000 to 4000 yards with N30A5 series of Locator
  • The sea state, nearby boats, marine animals, gas or oil lines, and other factors contributing to the ambient noise level will affect the range at which the beacon can be detected
  • 42A12/1 Ultrasonic Test Set, or TS200 Portable Test Set shall be used to perform operational tests on the beacon


OPERATING FREQUENCY:37.5 kHz ± 1 kHzOPERATING DEPTH:Surface to 20,000 feet
PULSE LENGTH:9 milliseconds minimumPULSE REPETITION RATE:Not < 0.9 pulse per second
ACOUSTIC OUTPUT INITIAL:1060 dynes/cm2rms pressure @ 1 meterACOUSTIC OUTPUT AFTER 90 DAYS:700 dynes/cm2rms pressure @ 1 meter
OPERATING TEMPERATURE:28°F to 100°FACTUATION:Fresh or salt water
RADIATION PATTERN:Rated output over 80% of sphereSIZE:1.3" D x 3.92" L (less mount)
BATTERY:Per TSO-142a, Replaceable

Contact us

Harlow Office: +44 (0)1279 86 87 86

or email