Boston as an independent consulting engineer, although he was also retained by his former employer as a "Consultant and Expert in patent causes". His first client was Herman W. Ladd, who was attempting to perfect his "Telelocograph" system for using radio signals as "wireless lighthouses" and for navigational direction-finding. Ladd's approach turned out to be impractical, but the work gave Stone insight about the difficulties facing the embryonic technology of radiotelegraphic signalling, and he recognized that his earlier work on resonant circuits on telephone lines could be applied to improve radio transmitter and receiver designs. Moreover, unlike most other early radio experimenters, Stone had the mathematical background needed to fully analyze electrical circuits. In late 1900, the Stone Wireless Telegraphy Syndicate was started in Boston, with an initial funding of $10,000, to do experimental work in devising a commercial system. Stone used his knowledge of electrical tuning to develop a "high selectivity" approach to reduce the amount of interference caused by static and signals from other stations. Starting with Tesla-style open-core electrical transformers, he developed adjustable "selective four-circuit tuning" that employed "loose coupling" to help insure that the transmitter and receiver were operating on a single common frequency. (In some cases an extra intermediary "weeding out" circuit was added, for additional selectivity. In contrast, transmitters operated by most other companies employed "close coupling" that produced signals on two separate frequencies). He also took special care to mathematically analyze transmitter and receiver designs to increase efficiency and reduce losses. In early 1900, he applied for a U.S. patent for his tuning work, which was divided into three patents that were issued in 1901 and 1902. In mid-1902 the Stone Telegraph and Telephone Company, also based in Boston, was formed, in order to begin commercial operations. Stone acted as Chief Engineer, and two stations separated by sixteen kilometers (ten miles) were constructed at Cambridge and Lynn, Massachusetts. Beginning in 1905, demonstration radiotelegraph stations, using spark transmitters and electrolytic detectors, were installed for evaluation by the U.S. Navy. By the end of 1906, the government had purchased five ship and three land installations. The company's first commercial radiotelegraph link was between the Isle of Shoals and Portsmouth, New Hampshire, which operated during the summer of 1905, replacing a failed Western Union telegraph cable. In 1907 Stone founded, and served as the president of, the Society of Wireless Telegraph Engineers (SWTE), which was created