cqd second - the cqd signal.
by G. E. TURNBULL
in The Yearbook of Wireless Telegraphy and Telephony, 1913, pages 320-322:

As time went on the organisation of wireless communication at sea became more and more perfect, and it was found desirable to embody in one Circular the various directions which had been given to operators regarding the use of the apparatus in the event of accident to the ship. Thus so long ago as January 4th, 1904, the famous "C.Q.D." call was instituted by the Marconi Co. and embodied in its "General Orders." This instruction, a landmark in the history of the organisation of wireless communications, is reprinted below from the original, which is carefully preserved in the archives at Marconi House.
When the "C.Q.D." signal achieved a lasting fame, on the occasion of the wreck of the S.S. Republic, many interesting stories were spread about as to its meaning and derivation. Probably the most amusing explanation of the signal was that it indicated "Come Quick, Danger," but perusal of the above Circular will show our readers exactly how it originated.
"C.Q." was the recognised signal used by one ship to attract the attention to it of others within hearing, so that telegraphic traffic could be commenced and transacted, and it was thought that the most appropriate distress signal would be arrived at by adding the letter "D." (denoting "Distress") to "C.Q.," the general call to attention.
It is a great compliment to the foresight of the Marconi Company in instituting, as they did at the commencement of 1904, a special distress signal, governing its use by stringent regulations, that the International Radiotelegraphic Convention of Berlin, which entered into force in July, 1908, ratified the practice in regard to distress signals initiated in 1904.
It is a matter of regret to some that the Berlin Convention should have superseded the old "C.Q.D." call by the new "S.O.S." This regret is shared by many of the oldest operators, and even when the new call came into force it is noteworthy that in each case of accident the "C.Q.D." call was sent out as well as the "S.O.S." The change of the call letter is, however, a sentimental regret, and "C.Q.D." is being gradually forgotten.
It is, further, instructive to note that the International Radiotelegraphic Convention which sat in London in June, 1912, endorsed the Marconi practice in regard to emergency apparatus by deciding that all ships equipped with Wireless Telegraphy should have an emergency set as part of their wireless equipment. This prescription comes into effect in July of the present year, but as by far the greater number of the merchant vessels of the world at present equipped with Wireless Telegraphy have been so fitted little change to existing arrangements will be necessary. The United States of America, which was a party to the London Convention, gave effect to the ruling of compulsory equipment with emergency apparatus almost immediately after the London Convention of 1912 was signed.
Much attention has been devoted to the design of apparatus suitable for distress calls, not only of special types, but also with a view to its handling by other than skilled operators. While it is true that a large number of passenger vessels are equipped with Wireless Telegraphy--and, indeed, only until a short time ago nearly all merchant vessels so equipped were passenger steamers--it is also true that a considerably larger number of cargo vessels are not fitted with this means of communication. Cargo-boat owners have hesitated to incur the cost of the equipment, and the expense of an additional person to be placed on board to operate it. Gradually these objections are being overcome by the simple question of pounds, shillings, and pence, it having been conclusively proved that this expense can be recovered many times over by considerations referred to elsewhere in this volume. With a view of simplifying equipments on small vessels (which in many cases may be able to fully justify the expense of their equipment by receiving distress calls and then proceeding to the assistance of the ship issuing them) it has been suggested that ships be so fitted and the distress call be so arranged that when issued this call should cause a bell to ring or sound a special alarm on board all ships within range.
In the earlier days of Wireless Telegraphy, when very few stations existed, wireless signals were registered by a Morse Ink Writer, or could be made to ring a bell. This could only be done by the use of that detector of wireless signals known as the coherer. This instrument had, however, so many inherent disadvantages, the chief of which were instability, slow rate of working, and necessity for constant attention, that it had to be replaced gradually by auditive reception, and its use at the present day, even for distress purposes only, has now become impracticable. Mr. Marconi, in answer to a question put to him at the Board of Trade Inquiry into the wreck of the Titanic, has shown how a distress call could be arranged under present methods of working to ring a bell or give some other alarm in ship station at a distance, and the method he suggested is now being worked out. Instead of the "S.O.S.," which consists of a series of dots and dashes, several long dashes would be used in transmitting. The special receiver would not respond to ordinary Morse signals made up of dots and dashes, to stray signals from other vessels communicating with each other, or to atmospherical disturbances, but only to a succession of long dashes, being actuated solely by the accumulation of energy in a long sustained dash. It goes without saying that the sustained dash, or series of them, would have to be longer than any existing Morse sign, and would have to be retained solely for the purposes of distress.
In cargo boats, where only one skilled operator is carried, the advantage of this arrangement is obvious, while in the case of any wireless station where it would be difficult to maintain constant watch at all times its utility cannot be gainsaid.
Meantime the best possible is being done in the way of giving members of the ship's crew an elementary instruction in Wireless Telegraphy on ships where only one operator is carried, to enable them to listen at the instruments while the operator is off duty. A short practice in Morse and in the handling of the receiving instruments will enable any intelligent person with normal hearing to detect the easily-distinguishable "S.O.S.," call in the event of its being sent out. He could then at once call the operator back to the station to attend to the communication.
We have referred above to lights, flags, rockets, guns, and sirens as means of distress signalling, and as accessories to wireless. We must not omit to mention as another and one of the most valuable accessories of the present day--namely, that of the Direction Finder, or, as it has been termed, the Wireless Compass. By means of this invention it is possible to detect, independent of weather conditions to which visual means of signalling are subordinate, the direction of one vessel in respect of another. The range of this instrument in the average mercantile equipment extends up to 50 or 60 miles. Neither must we omit to refer to one more invaluable accessory to Wireless Telegraphy in summoning assistance to a distressed vessel, and that is the submarine signalling apparatus. The apparatus is arranged with one receiver on the port side, and another on the bow of the ship, for direction finding, but as the detection of sound by this means is limited at present to between 10 and 15 miles it can only be used as an adjunct to the direction finder, and as a check upon the readings of the latter, should it be desirable to have them up to ranges within these figures.
To describe distress signalling in all its details as it can be accomplished at the present day, and to discuss fully all its possibilities, would fill many pages more, but a general survey only has been attempted here with a view of noting the principal features. If this essay has conveyed to the mind of the reader a fair understanding of what is actually being done and what is still possible, if it has impressed upon him that science and invention are being energetically applied in this direction, under the watchful and encouraging patronage of the Authorities at home and abroad, he will be assured that everything humanly possible is being done to diminish the perils of the sea.
 
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