PRE AND POST 1912

From the earliest days of wireless telegraphy, Marconi and his Company controlled the commercial side of radio, and, after much in-fighting, won the day on the naval side too - the story of Captain Jackson Royal Navy {latterly an Admiral of the Fleet} and Marconi himself is legendary.  Marconi was omnipotent, supervising the fitting of ship wireless stations and subsequently supplying the radio officers to man and operate the equipment. His influence over shore radio stations was almost total.

From the very beginning of his invention in the last years of the 19th century until 1912, Marconi had radio installations and radio officers in virtually every merchant ship afloat irrespective of the ship's country of origin or flag.  His control was not limited to the 'technical' side of wireless telegraphy only, for he laid down the operations and procedures to be followed in the daily use of the medium.  Moreover, he chose the ship station callsigns, and every ship carrying his equipment/officers had a callsign which began with the letter 'M' for Marconi: at this period, callsigns were three letters. Very few ships around the world had a callsign which didn't begin with the letter 'M'.   Other ships,  fitted with wireless telegraphy equipment, used  three letter callsigns with the first letter denoting their country i.e. the letter 'D' for Deutschland {although that country was always known as Allemagne in those days}.

To give a indication of the monopoly Marconi had on the 'use' of wireless telegraphy, I refer you to the RMS Titanic sinking in 1912. No fewer than twenty six ships were involved with that tragedy as well as many radio shore stations, also monopolised by Marconi.  Of the twenty six, twenty were 'Marconi Ships', one was a USA warship {USS Chester}, four were German {with 'D' callsigns} and one was Greek [with an 'S' callsign}. The 'Marconi Ships' are listed in the following table which also shows their radio callsign at the time of the tragedy.

NAME OF SHIP MARCONI RADIO CALLSIGN
ANTILLIAN MJL
ASIA MKL
BALTIC MBC
CALIFORNIAN MWL
CARONIA MSF
CARPATHIA MPA
CELTIC MLC
CEDRIC MDC
FRANCONIA MEA
EMPRESS OF BRITAIN MPB
LA TOURAINE MLT
TITANIC MGY {was originally MUC}
MOUNT TEMPLE MLQ
MESABA MMU
MINNEHAHA MMA
MINNEWASKA MMW
NOORDAM MRA
OLYMPIC MKC
PARISIAN MZN
VIRGINIAN MGN

Also in 1912 {post Titantic}, in London, there was an International Radio Conference.  At this conference it was agreed that every maritime nation would have its own unique series of callsigns, thereby introducing the system we have today, namely INTERNATIONAL CALLSIGNS. There was no provision for whether the callsign would be three or four letters, or indeed any other combination, but as demand grew, the four letter callsign became the norm *. Marconi lost his control over callsign allocation, but not over his monopoly of supply and service which was to be eroded by international commercial competition.

As an epilogue I can tell you that the Titanic's sister ships, the Olympic and the Britanic, eventually took the callsigns GLSQ and GDXF respectively.

This page comes from a 1913 document and shows more callsigns of British ships.  Note that those with an asterisk are WARSHIPS. Note that they all began with the letter 'S' - {However Invicta should have an asterisk and so too should the Iphigenia but the Ionic should not have one.   Note also, the continuation of Marconi's ships all beginning with the letter 'M'.  Naval frequencies [wavelengths] were classified but those commercial wavelengths mentioned equate to λ =150 = 1.5MHz:  λ=300 = 1MHz:  λ=600 = 500kHz.

The warships listed were as follows:-

HMS Hyacinth = Cruiser 5600 tons
HMS Illustrious = Pre Dreadnought Battleship 14900 tons
HMS Implacable = Battleship 15000 tons
HMS Indefatigable = Battlecruiser 20000 tons
HMS Indomitable = Battlecruiser 20000 tons
HMS Inflexible = Battlecruiser 20000 tons
HMS Intrepid = Built as a "Protected Cruiser".  In 1910 converted to a Minelayer 5000 tons
HMS Invicta = Pre Dreadnought Battleship 14900 tons
HMS Invincible = Battlecruiser 20000 tons
HMS Iphigenia = Built as a "Protected Cruiser".  In 1910 converted to a Minelayer 5000 tons
HMS Irresistible = Pre Dreadnought Battleship 14900 tons
HMS Iris = Sloop 1600 tons
HMS Juno = Protected Cruiser 5600 tons
HMS Jupiter = Battleship 14900 tons

However missing from this list is the callsign SBZ which was the naval "vessel" HMS AIR SHIP 1.
 

* Now, we are running out of four letter callsigns: see BAD NEWS FOR UK RADIO CALLSIGNS. See also MERCHANT SHIPS IN 2004 particularly the part, just after the snippet about the Aurora, concerning callsigns.