NIPPON OKI ODS 5550 1 MARINE TELEPHONE MFG NO 179

NIPPON OKI ODS 5550 1 MARINE TELEPHONE MFG NO 179

The Nippon Oki ODS 5550-1 is a robust, fully synthesized VHF-FM marine radiotelephone designed for professional and commercial maritime use during the 1980s. As a product of Nippon Oki Electric Co., Ltd. (often stylized as OKI), a renowned Japanese electronics manufacturer, this unit was built to the high standards of the era, emphasizing reliability, clear communication, and durability in the harsh marine environment.

Its Manufacturing Number 179 and designation as an SEO Product likely indicate a specific production batch or a variant supplied for a particular market or customer (SEO could stand for a specific export order or a systems engineering office).

Key Features & Specifications

1. Communication & Channels:

• Frequency Range: Covers the international marine VHF band (approximately 156 MHz to 162 MHz).

• Channels: Fully synthesized, providing all international, USA, and Canadian marine VHF channels as standard. This includes:

  • Channel 16 (156.800 MHz) – International Distress, Safety, and Calling.

  • Channel 70 (156.525 MHz) – Digital Selective Calling (DSC) – Note: This unit predates DSC and would not have DSC capability.

  • Standard ship-to-ship and ship-to-shore channels.

• Weather Channels: Typically included receive-only capability for NOAA weather channels (WX1-WX3) in the US, allowing mariners to listen to continuous weather broadcasts.

2. Power & Output:

• Output Power: Selectable high/low power.

  • High Power: 25 Watts (the legal maximum for ship stations). Used for long-range communication.

  • Low Power: 1 Watt. Used for short-range communication in harbors or when close to other vessels to reduce interference.

• Power Supply: Designed to operate from a standard 12V DC negative-ground shipboard power system.

3. Design & Construction:

• Form Factor: A classic, compact “black box” main unit designed for fixed installation at a navigation station, typically connected to a remote control head and an external antenna.

• Durability: Built with a metal chassis and case to withstand vibration, moisture, and salt spray.

• User Interface: The main unit features connectors for power, microphone, remote head, and antenna. The operational controls (channel selector, volume/squelch, power switch) were likely on a separate, connected control panel.

4. Functionality:

• Squelch Control: A manual squelch control to eliminate background noise when no signal is present.

• Dual Watch: A feature that allows the radio to monitor Channel 16 and another selected channel simultaneously.

• Public Address (PA) Function: Many units of this type included a PA mode, allowing the radio to broadcast through an external speaker on the deck.

Typical Use Case & Vessel Application

The ODS 5550-1 was a professional-grade radio suitable for a wide range of vessels, including:

• Commercial Fishing Boats

• Workboats and Tugs

• Medium to Large Private Yachts and Sailing Vessels

• Small Ferries and Commercial Craft

Its 25-watt power output made it reliable for communication with coast stations (Marine Operator services, which are now largely defunct) and other vessels within a typical VHF range of 20-30 nautical miles.