The concept electricity took shape in the early 19th century by means of the scientists Volta, Ampère, Ohm,
Léclanché, Örsted, Hertz, Faraday and others. The voltage (volt) has been derived from the Italian Volta and
the current (ampère) from the Frenchman Ampère. The German Ohm discovered the connection between
voltage, current and resistance, recorded in the Ohm’s law (I=V/R). Léclanché designed an electric element
that was the basis for the battery of today.
The electric capacity (farad) was derived from the name of the physicist Faraday. Örsted demonstrated the
relation between magnetism and electricity. Heinrich Rudolph Hertz showed the existence of Maxwell’s
wave movements and gave consequently his name to the division of the frequencies, the hertz (Hz).
The American lawyer and portraitist Samuel B. Morse during the crossing from Europe to North-America invented
in 1832 the morse alphabet, meant as long distance communication device, with which signs could be sent by
means of electricity. Between two offices electric current was switched on and off by means of a telegraph key
in the rhythm of morse signs. A receiving machine reacted to this switching and wrote automaticly the
dots and dashes on a narrow movable paper strip situated on a reel. The first public telegraphline was
realized between Baltimore and Washington in 1845.
Morse designed an alphabet suitable for:
26 characters, 12 punctuation marks, i.e. - = : , . ? / “ + ‘ ( )
10 figures and the indications -.-.- (begin), .-.-. (end), .-… (wait) and …….. (mistake).
The most used characters were kept short and the less often used characters long. This way one could send a
message at a reasonable speed.
In practice it is possible to send an average of 25 words per minute (or 125 characters). The speed of the
transmission is adapted to the quality of the contact and the capacity of the opposite collegue.
Abbreviations were invented to shorten a long story. Many of these abbreviations were used, such as:
CQ = call to all stations ETA = estimated time of arrival
WX = weather bulletin SLT = ship letter telegram
SVC = service message COL = repeat certain figures of a message
RPT = repeat CFM = confirm
NIL = nothing to send to you BN = all between ….. and ……
AA = all after …. AB = all before …. WA = word after …. WB = word before ….
Three character codes were designed to shorten sentences, such as
QRA the name of my station is ……….
QTP . I’m going to enter the port of ……….
QRK 5 the intelligibility of your signals is excellent
QTC 3 I have three telegrams for you
QSW 8391 I’m going to send on 8391 kHz
QRZ ? who is calling me ?
QRX 1630 I will call you again at 1630 GMT
QSP 2 PCH? are you willing to relay 2 telegrams to PCH free of charge ?
In 1895 Marconi in Bologna succeeded in generating electromagnetic waves (radio) and was able to transmit
wireless morse signals. He managed to do this by means of the so-called “sparkbridge of Righi”, a big induction
spool and an adapted Branly coherer. The first radio contact bridged two kilometers from Marconi to his brother
with a primitive receiver.
Marconi's first transmitter by which he in 1895 sent the letter Sfrom his father's garden to his aid Magnani three kilomters away
His invention met with little or no response in his own country, so he left for England. Here he found out that not
only electromagnetic groundwaves were generated, but waves in space as well. He noticed that if the wavelength
was changed, the distance to cross was influenced. In 1889 he transmitted across The Channel and on December
12th 1901 a distance over 2000 nautical miles was bridged by transmitting the character S in morse (three dots)
from Poldhu in Cornwall to Signal Hill near St. Johns on New Foundland.
In 1899 the German s.s. “Kaiser Wilhelm der Große”, bearer of the Blue Riband, was the first ship to be equipped
with long- and middlewave radio, one year later followed by the lightvessel Borkum. Within ten years also the short
waves were discovered.
In 1904 the PTT-coaststation Scheveningen Haven (later Scheveningen Radio) was founded, rapidly followed
by Norddeich Radio in Germany, Lapanne Radio (later Oostende Radio) in Belgium, New York Radio in the U.S.A.,
Portishead Radio in the U.K. and St. Lys Radio in France.
.
International the following was regulated:
a) The wavelength 600 meters (500 KHz) became (and still is) the distress- and callingfrequency. Radio
broadcasts begin at 540 KHz; nautical radiotraffic takes place between 405 and 535 KHz
b) Initialy the distresscall was CQD (seek you, distress), but as CQ was a much used general call
this was not satisfactory. It had to be a signal which would draw attention between
all other morsesignals; thus the characters S, O and S were transmitted together (…---…).
The unofficial meaning Save Our Souls was given to this signal.
c) Nautical frequencies were also allocated in the longwave band and the shortwave bands 4,
8, 12, 16 and 22 MHz (later also 25 MHz).
The following requirements for a ship’s radiostation were made:
- The radiostation has to be situated as safe as possible in the upper part of the ship
- The prescribed emergency source of power (accumulators) for the installation has to be situated as high and
safe as possible.
- An effective connection between the radiostation and the bridge must exist (megaphone or independent
telephone connection).
- There must be a reliable timepiece showing Greenwich Mean Time (GMT). The face of the clock has to show
the silentperiods for radiotelegraphy and radiotelephony.
- The radiostation has to be equipped with a reliable emergency lighting, operating independent from the
main lighting.
- Tools and the necessary reserve radiotubes, transistors and fuses have to be present.
- A complete reserve antenna, suitable for immediate hanging, has to be present.
- A fire extinguisher with a capacity of maximum 2 kg dry powder or carbonic acid CO2 has to be
fitted in the direct vicinity of the radio installation.
- The radiostation has to be operated by someone in possession of a certificate of proficiency
in radiotelegraphy of the second (or first) class.
When the Titanic sunk in 1912, the sparks used on the 500 KHz the old and new distress signal:
CQD SOS de MGY = we have struck iceberg sinking fast
come to our assistance position lat 41.46N long 50.14W = MGY
Only a few ships heard the call. On the freighter Californian, at a distance of some 18 nm, rockets were seen,
but no action was undertaken because it was presumed there was a party going on on the big ship.
The sparks could have proved the contrary, but he was off duty and was asleep at that time.
This resulted in a new radiowatch arrangement for radio operators. During the daytime four radiowatches of two
hours each were kept with two hours of free time in between. In this way there was no listening watch on the
distress frequency, so a receiver was developed that reacted on an alarmsignal transmitted by a ship in
distress (8 dashes of 4 seconds eacht devided by an interval of 1 second).
This receiver activates three alarm bells, one situated on the bridge, one in the radioroom and one in the
sparks’ bedroom. The intention of course is to reach the radioroom as soon as possible to switch off the noise
and to listen on the distress frequency. Happened the distress to be too far away to go for assistance the
sparks returned to his bed empty-handed and in a bad mood.
The question whether or not to proceed for help in a case of distress depends on the distance, are there
(enough) other ships closer to the distress position and the time it will take to reach the ship in distress.
All this is for the captain to judge, who will be kept informed of the latest developments that can make him
to decide to set course to the ship in distress.
Radioroom s.s. "Melchior Treub" (K.P.M.)
Anticipating on the chapter “The training” I’d like to quote former radio operator and former director of Radio-
Holland J. Grootes, the author of “The textbooks of Regulations”, in which he outlines in part 1 a brief
summary of distress traffic:
The commander (captain) orders the radio operator to do whatever is necessary to obtain help, as soon
as he considers that the situation gives him the right to do so, in other words when his ship is in serious and
instant ominous danger and needs immediate assistance. As a rule the radio operator starts with the
transmission of the alarm signal.(He will refrain from doing that only then when the captain tells him that there
is no time left).If circumstances allow him, he waits for 2 minutes prior to transmitting the distress call.
In this case he transmits in those 2 minutes, immediate after the alarm signal,three times the distress
signal. If circumstances do not allow him to wait 2 minutes, he transmits at once after the alarm signal the
distress call (on which no receipt will be given).
After this he transmits as soon as possible, i.e. as soon as he has received the necessary information from the
bridge, the distress- m e s s a g e. Receipt will immediately been given by those stations which are doubless
in the vicinity,while stations doubtless not in the vicinity shall give more favourable situated stations the
opportunity to send a receipt.
The radio operator of the station in distress passes those receipts on to his captain immediately. It is true
this information is of no use to the captain, but at least he is reassured that several ships are in his vicinity.
The radio operators who gave receipt, did that on their own authority and had notified their captains of the
case of emergency. Furthermore they write the entire distress traffic in the radio logbook.The captains then
compose a message as supplement to the receipt and as soon as the captain of the ship in distress gets notion
of this message, he can proceed to claim one or more ships, which seem to be the most suitable.
Are captains notified by their radio operators that the claimed ships carry out the claim or do they consider
that, on base of any regulation of the International Treaty of Safety of Human Life at Sea, they are exempted
from the obligation to render help to the persons in distress, then they resume their normal route to the
port of destination.The job of the radio operator however is n o t ended. His exertions with the distress
case are over when he receives the message that announces the end of the distress traffic.
Of all telegrams belonging to the distress traffic the call and the official introduction start with the distress
signal.
Some abbreviations used during distress traffic:
QUF - I received a distress signal sent by ………. (callsign of the distress station)
QUM - Normal working may be resumed
QUI? - Are your navigation lights functioning ?
QUN - My position, true course and speed are ……..
QUR2 - Survivors have been picked up by rescue vessel
QUS? - Have you sighted survivors or wreckage? If so, in what position?
QUT? - Is the position of the incident marked?
A (relayed) distress message sent by Land’s End Radio/GLD in connection with a truly happened distress case
in the entrance of The Channel, directly south of Land’s End.
ddd sos sos ddd de gld gld = from henriettab/ovrh on 2182 khz at 0420 gmt begins mayday 13
crew members onboard heavy list my posn is 49.10n 05.30w I am in sinking condition immediate
help necessary stop I am trying to attract attention of french warship nearby me = gld 140420z +
col 2182 13 49.10n 05.30w+ gld
ddd sos means the the transmitting station (GLD) itself is not in distress, but is realying the distress message of the
ship in distress.
Land’s End Radio/GLD intercepted at 0420 GMT on 2182 kHz a distress message from the Danish ship Henrietta
B/OVRH with the text shown above.
Land’s End Radio finishes with the date/time group and repeats the figures in the message.
With the transmission GLD achieved that the distress message sent on the telephony distress frequency 2182 kHz,
was received ty bigger ships, that listen 24 hours a day on the telegraphy distress frequency 500 kHz, partly by
ear and partly by the automatic alarm receiver.
Persons at the base of modern communication
Persons eternal inseperable connected by Ohm’s Law.
André Marie Ampère (1775-1836), Alexander Volta (1745-1827),
who gave his name to the unity of current, the ampère. who gave his name tot the unity of voltage, the volt.
Georg Simon Ohm (1787-1854), who gave his name tot the unity of resistance, the ohm.
Ohm's Law: I=V/R , V=I*R , R=V/I , W=V*I
Heinrich Rudolph Hertz (1857-1894), Guglielmo Marconi (1874-1937),
gave his name to the division of frequencies, In 1895 he was the fist one to transmit
the hertz waves, or Hz signals wireless over a distance of 2 km.
Samuel Finley Breese Morse (1791-1872), the American lawyer and portraitist,
who invented a language composed of dots and dashes, with which telegraph
messages could be sent and would later be used for radio communication.
In 1845 he opened the telegraphline Baltimore-Washington
with the words: “What hath God wrought?”
Two pages from Morse’s sketchbook (1832) with the initial plans for the morse code.
.-.-.