HISTORY OF VHF!

Early days

Marine  radio was first installed on ships around the turn of the 20th century.

In those early days, radio (or "wireless" as it was known) was used primarily for transmission and reception of passenger telegrams.

Radio watchkeeping hours were not standardised, and and there was no regulatory requirement for carriage of radio by ships.  Indeed, there was a general lack of regulation of the radio spectrum.  

Amateur/experimental stations often interfered with commercial stations and vice-versa. 

All that changed one clear and cold April night in 1912...

The most modern passenger liner of the time, RMS Titanic, sank on her maiden voyage after a collision with an iceberg. 

Some 1500 people perished in the disaster.  Fortunately, 700 odd people were saved, thanks mainly to the efforts of the Titanic's two radio officers, who managed to summon help from nearby vessels.

The only known photo of the Titanic's radio room

However, the vessel closest to the disaster (the Leyland liner Californian) could not be summoned, as her Radio Officer had just gone off watch after 12 hours on duty. The Californian managed to establish communications with other searching vessels after the Titanic had sunk.

But by then, it was too late - one thousand five hundred people, including the cream of American and European society, had frozen to death in the North Atlantic.

The Titanic disaster brought about a number of fundamental changes to marine radio:

 - carriage requirements and radio watchkeeping hours were standardised;

 - message priorities were standardised - i.e.: distress and safety traffic always has priority;        

 - distress frequencies were standardised; and

 - radio silence periods were introduced.

The Titanic disaster also served as the catalyst for the introduction of the International Convention for the Safety of Life At Sea (the SOLAS Convention).  The introduction of the first SOLAS Convention was delayed by WW1 - the Convention came into force in the 1920's.

For more detailed information on the radio aspects of the Titanic, have a look at the RMS Titanic Radio Page.

1920s-today

During the 1920's, 30's and 40's, marine radio advanced with the technology of the day - radiotelephone operation was introduced, and most importantly, High Frequency (HF) came into widespread use, thereby allowing communications over ever-increasing distances.

Radio room - RMS Queen Mary

Of course, marine radio played a vital role in WW2 - the war provided a great boost to radio technology in general.  Amongst other things, WW2 introduced direct bridge to bridge communications, through the use of what was to become the marine VHF radio band - known during the war years as "talk between ships" (TBS).

After the war, Marine Radio incorporated the latest achievements in electronics - solid state (i.e.: transistorised) equipment and Marine Radar became commonplace.

However by the late 1970's, despite tremendous general advances in communications, Morse Code still ruled the marine radio waves.

After some 80 odd years of development, marine distress alerting still relied on a human being sitting in front of a receiver. 

Ship's Radio Officers sent a distress message using Morse Code (or radiotelephone) in the hope that another ship or shore station would hear the call and respond.

Typical merchant ship radio room - mid 1980's..note the morse key

The main Marine Radio distress frequency of 500 kHz had remained unchanged since the Titanic had sent her plaintive calls for help that April night in 1912... The stage was set for some significant change....

  Time for a change...

Since the time of the Titanic, Marine Radio has helped to save tens of thousands of lives, and become the key element in Marine Search and Rescue (SAR).

Without radio, there can be no SAR...

Before the Global Maritime Distress and Safety System came into force, marine radio equipment was required to provide operation over a minimum specified range of 150 nautical miles.

This was based on the (not unreasonable) assumptions that ships usually travelled well-used routes and that there were sufficient ships at sea and shore stations dispersed about the world to receive distress calls.

However, if a ship was outside of the normal shipping lanes or was rapidly overwhelmed by the forces of nature, her distress alert may go unheard.... many ships have gone to the bottom without any distress signal being sent - they have "sunk without trace".....

The pre-GMDSS systems were, in reality, based on 1920's technology....

A new system

The International Maritime Organization (IMO) pondered the shortcomings of the existing marine distress systems in the mid to late 1970's.

The 1979 IMO Assembly decided that a new global distress and safety system should be established in conjunction with a coordinated SAR infrastructure to improve safety of life at sea.

And so was born the Global Maritime Distress and Safety System (GMDSS).

The GMDSS is designed to automate a ship's radio distress alerting.  It removes the requirement for manual (i.e.: human) watchkeeping on marine radio distress channels.

The new system is quicker, more efficient and reliable than the old manual Morse Code and radiotelephone alerting systems.

The basic concept of the GMDSS is that Search and Rescue (SAR) authorities ashore, as well as shipping in the immediate vicinity of the ship or persons in distress will be rapidly alerted so that they can assist in a coordinated SAR operation with the minimum of delay.

One of the principal advantages of the GMDSS is that the system is actually an amalgam of various individual radio systems, both terrestrial and satellite.  Distress alerts may be sent and received over short and/or long distances, by ships of all sizes.

In other words, every ship is able to perform those communication functions which are essential for the safety of the ship itself and of other ships operating in the same area - irrespective of the area through which it sails and its size...

Credits: Google Images.