The early history of "wireless" is sometimes a bit confusing, because the term "wireless" referred broadly to a number of similar technologies. The earlier "induction" method employed by Preece was able to signal for relatively short distances, but it also required long transmitting and receiving wires, arranged in parallel lines, which were approximately as long as the distances being bridged. Marconi's use of a spark transmitter to produce electro-magnetic radiation (radio waves) was a much more compact and efficient technology, especially when he began to use longer wavelengths than those described in this initial report.
Scientific American, January 23, 1897, page 56:

Telegraphy  Without  Wires.
    An invention which promises to be of the greatest practical value in the world of telegraphy has received its first public announcement at the hands of Mr. W. H. Preece, the telegraphic expert of the London post office. During the course of a lecture on "Telegraphy Without Wires," recently delivered in London, Mr. Preece introduced to the audience a young Italian, a Mr. Marconi, who, he said, had recently come to him with a system of telegraphy without wires "which depended, not on electro-magnetic, but on electro-static effects, that is to say, on electric waves of a much higher rate of vibration, not less than 250,000,000 a second; that is, Hertzian waves." These vibrations were projected through space in straight lines and, like light, were capable of reflection and refraction, and, indeed, they exhibited all the phenomena which characterized light.
    Telegraphing without wires was, of course, no new idea. Mr. Preece stated that in 1884 operators in the telephone exchange, London, were able from sounds heard to read messages that were in transit from London to Bradford by the telegraph wires. The post office wires were underground and the telephone wires above ground, and careful experiment showed that this fact accounted for the telegraphic messages to Bradford being read by the telephone company. In 1893 telegrams were transmitted a distance of three miles across the Bristol Channel by induction, and during a break in the cable connecting the island of Mull with the mainland communication was established by means of parallel wires as follows: On the mainland an insulated wire was laid along the ground, earthed in a running stream at one end, the other end being in the sea. Skirting the coast of the island was an overhead wire suited to the purpose. In the course of four days one hundred and fifty-six messages were dispatched.
    The invention of young Marconi solved the problem on entirely different principles. The post office officials had used it successfully on the roof of the general post office, and then made a successful test on Salisbury Plain at a distance of three-quarters of a mile. The great difference between the Marconi and the inductive methods of wireless telegraphy was that the former did away entirely with the wires at each end. Vibrations were set up by one apparatus and received by the other.
    The apparatus shown at the lecture consisted of two plain boxes which were placed at opposite ends of the hall. The current was set in motion in one box, and immediately a bell was rung in the other. Mr. Preece said that the British post office authorities had decided to spare no expense in experimenting with the apparatus and one of the first trials would be from Penarth to an island in the English Channel.
    If the experiments were successful, it would be of inestimable value to shipping, for it would provide another easy way of communicating with lightships and lighthouses. To take an instance: Since last year they had had a cable with the Fastnet Light (the first light seen by Atlantic voyagers), but in the early part of this year it broke down, and they had never been able yet to land on the rock in order to repair it. But there was a possibility beyond this of enabling ships as they came near dangerous seeks and shallows to receive an intimation of the fact by means of these electric waves. Neither day nor night made any difference, fog or rain or snow would not interfere with them, and if the invention was what he believed it to be, our mariners would have been given a new sense and a new friend which would make navigation infinitely easier and safer than it now was.