At the time the Titanic sank in 1912, there were no laws regulating radio in the United States, and for years there had been complaints about interference caused by undisciplined amateur operators. In the hours following the Titanic's sinking, amateurs were blamed, perhaps unfairly, for causing problems in getting accurate information from the rescue ships. In any event, this extract reports how, during the next night after the sinking, amateur transmitters around New York City voluntarily maintained complete radio silence, in order to aid the reception of signals coming from ships reporting Titanic information.

The Book of Radio, Charles William Taussig, 1922, pages 203-205:

    Many other stories of amateur usefulness in times of trouble can be told. The author recollects a case of such assistance, which was rendered by amateurs on April 15, 1912. On the previous day, the Titanic had struck an iceberg and sunk with an appalling loss of life. Effort was being made to rush a list of the survivors to the newspapers, but owing to the severe atmospheric conditions, the scout cruiser Salem near the scene of the disaster was finding it difficult to get the names through to the naval stations at Newport, Rhode Island. This was prior to the radio law, and every evening around Greater New York, the air was full of pleasantries, foolishness, bantering, squabbling, quarreling, jamming in both the Morse and Continental codes, for at that time both of these codes were in use on the wireless. There was no organization then to line up the amateurs and keep them from interfering with the important work that was going on. But that invisible bond which binds them to one another, held them in check that night for the important work to which they were to contribute their share.
    New York's little radio population was aghast the morning after, when they read of the horrible disaster. Each and every one thought unto himself, "How can I be of some assistance?" Little by little, news was arriving in New York, giving some of the details of the horrible event. Anxious relatives were awaiting word of the survival of their dear ones. The newspapers told them that the names of the survivors were being held up, due to the severe static disturbances in the ether, and when night came, only a partial list of the survivors had reached New York.
    Without being told, and with no organization to get them together, the amateurs of New York and vicinity discovered the part that was allotted to them to render assistance in this tragedy of tragedies. At eight o'clock the evening following the sinking of the Titanic, when the author picked up his telephone receivers and tuned in on that little world of ether, he was not greeted by the usual din and noise, but in its stead was an oppressive, awful shroud of silence. Except for the mournful rumblings and grumblings of the static, not a sound was to be heard, and yet every amateur was at his post, with the self-imposed grim task of trying to copy the names of the survivors of the Titanic that the valiant little ship, the Salem, not far from the scene of the disaster, was trying to get through to the Newport Naval Station. 'Twixt static crashes, they were copying the names of those who were fortunate enough to be saved from a watery grave.
    Hour after hour, they copied what little they could get, for the static would at times completely obliterate the signals from the Salem. Twice during the long period, the silence was broken; once by the German station in the Trinity Building on Broadway, TWT. Hardly had their loud spark been impressed upon the ether, when the stentorian spark of Dr. Hudson, the most prominent amateur at that time, warned them to keep out. Dr. Hudson was the self-appointed patrolman that night and his spark was the law and no one disputed its authority. Once again during the long night, an amateur sent out a call, but he also bowed to the reproving signals from old "D. R."
    All through the night, they labored at their task, and when morning came, fragmentary records of the messages sent out by the Salem, pieced together with the messages copied by the Newport Naval Station, enabled the newspapers to bring cheer to the homes of many, by the publication of a full list of the survivors of the Titanic.