Digital processing of foghorn sounds

Excellent performance

The AlphaSSRS is a complete Sound Signal Reception System (SSRS) consisting of a display and antenna, designed to receive and detect foghorn sounds from other vessels and is for use onboard one-man operated enclosed bridge class ships. The display features an adjustable volume and dimmer and is highly suitable for fore and aft bridge mounting.

The sound reception system enables the watch officer to receive warning signals of nearby vessels within a 70 to 2100 Hz frequency from all directions and suppresses unwanted background noise allowing reception of only relevant sounds.

Displaying signals

In standard mode, the unit will be idle until a horn signal is detected. Detected horns will play on the speaker and indicate the direction of the source of the signal.

Within the first 3 seconds of detection, an 80° arch will light up in orange while the center of the arch is lit in red. After 3 seconds only the red light remains active and the indication pointer will remain for a configurable amount of time (7 seconds by default) visible after the detection is finished. Multiple indications can be active at once.

Web interface

A secured web interface is used for logging and configuring the system. It also provides the system status, making it is easy to get access to settings, parameters and errors of the sound signal reception system which can save time during trouble shooting. At the same time, the website interface allows you to easily maintain the system for firmware updates, reset or factory restore functions.

Within the web interface you can get an overview of syslog messages which are sent to specified network addresses. You can set up the three proprietary sentences; Sound Reception Signal (SRS), Volume (VOL) and Heartbeat (HBT), but it is also easy to check the DCC sentence for central dimming control through the network.


The SSRS antenna unit consists of 4 microphones. The acoustic and visual rendition of a received incoming foghorn signal is reproduced and amplified through the SSRS display and processing unit on the bridge.

The antenna unit features a flexible bracket which allows horizontal or vertical installation. The antenna unit comes with a 3 meter multi cable as a pigtail. The wire leads must be terminated in a junction box suitable for the environment. From this location a cable must be installed to the display unit.