Most early radio stations used simple spark transmitters, whose transmissions often spread broadly over much of the band, causing significant interference, especially to the crude equipment used at this time by the U.S. Navy. In this article, there are numerous references to the need for perfecting "syntony", which is an older term for "tuning".
 
Electrical World, March 3, 1906, pages 437-438:

REGULATION  OF  WIRELESS.
    The cruise of the Dewey floating dock across the Atlantic gave opportunity for some very valuable practice in long-distance wireless telegraphy, messages from the guardians of that huge but not speedy craft having been received over something like 1,800 miles. These records were made, of course, under the favoring shelter of night, like practically all the other long-distance records. This is very encouraging, albeit it chances to be coupled with home news of a somewhat amusing character, when some high school boys of an experimental turn of mind threw the Newport naval wireless station into a succession of fits with an old Morse key, a broken incandescent lamp and a few dry batteries. These youngsters had the commendable Yankee spirit and no desire to make trouble for their country's defenders. They gave incidentally a valuable demonstration of the need of improvement, to which we trust the Navy Department will give due heed. If such rudimentary equipment accomplished so considerable a disturbance, what would happen if a hostile fleet went deliberately to work with powerful and skilfully devised apparatus? Of course, in working disturbance at a distance, much more power is needed than when working nearby. Still it appears safe to conclude that the navy system as now used could be hopelessly, tangled up, without going to much trouble. And the same so far as has yet transpired is true of every other wireless system in use for practical purposes. Where is the syntonic wireless of which we have heard so often enthusiastic reports?
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    Of course, for long-distance work everybody likes to use as long waves as practicable, and there being limits on the feasible lengths of vertical antennæ, the natural tendency is for all hands to use waves of about the same order of magnitude. The work of these Newport boys, however, signifies that with the apparatus now commonly used one can get interference with almost any sort of sending wave provided it carries a reasonable amount of energy. If there is any such thing as a syntonic system, it is high time Uncle Sam hunted it up with a view to adoption. There have been many very ingenious schemes of syntonism proposed, and if any one of them is really effective his owner should pack up his kit and head for Newport. His welcome is already guaranteed. Meanwhile, it is time something were done in the way of preventing malicious or improper use of private wireless stations. There is no need of interfering with legitimate experimenting. These boys with extemporized outfits may some day help the Government out of a scrape, but means should be provided to confine their efforts within definite bounds, just as it would be proper to check indiscriminate trials of searchlights in the neighborhood of lighthouses. The rights of the Government in the regulation of commerce would seem to be sufficient to cover the case, if judiciously exercised. Perhaps as good a way as any would be to require the registration of wireless stations, without expense, and their operation under permits revocable for persistent misuse or other sufficient cause. It would be an excellent thing for the Government thus to keep in touch with all the available experts on the subject, so as the more readily to utilize their services in case of need. State authority is sufficient in this case, as all wireless stations are willy-nilly engaging in impromptu interstate commerce. One of the serious dangers is that various enterprising newspapers may undertake to install private wireless plants for perfectly legitimate ends, but in such wise as to cause very serious trouble.
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    Suppose, for example, one of our metropolitan dailies were to arrange with its Washington correspondent for a regular wireless service reporting every evening the proceedings of Congress, and were imitated by one or two others. Things would be lively all along the coast, and officers anxiously awaiting reports from incoming vessels would not be particularly edified by an hour-long speech of the member from Buncombe. The international aspects of the case are not very serious in the United States, but rise to vital importance in Europe where distances are smaller. Altogether the new art presents some rather startling problems, quite aside from the technical ones, and it looks very much as if something rather sweeping would have to be done, not in repression, but in friendly and thorough regulation. Meanwhile the inventors who are working on the subject ought to contrive some effective means of preventing interference. At least half a dozen such have been announced, of which none to our knowledge has as yet amounted to much. The difficulties in syntonism are, of course, great. The sending apparatus must be able to deliver waves of one or several very definite wave lengths, and the receiver must respond to these and to these alone irrespective, within wide limits, of the strength of the impulses. Here seems to be the major part of the difficulty. If directed waves could be sent out, the questions of interference would be simplified, and some experimenters have been striving to accomplish this end, with some hopes, at least, of success. The whole situation has become very complicated and unless something is done about it soon the effect will be like a telephone exchange with all the subscribers on the same line and all trying to talk at once. We believe strongly in the potency of individual effort, and look with distrust upon too intimate Governmental control of private enterprise. Nevertheless, the time has now come when in wireless telegraphy it is either regulation or chaos, and of the two the former is certainly to be preferred. Its proper form is not altogether clear, considering the various interests involved. Surely, however, sufficient regulation to prevent frequent and serious interference with service can be applied without material injury to any one disposed to fair dealing.