Exhibition hall

Exhibition Room
on History of Wireless Communications

In order to further deepen the understanding of the history of wireless communication, the Exhibition Room was opened with the cooperation of exhibitors, mainly companies of the Yokosuka Research Park (YRP).　Please take this opportunity to visit and see the achievements of our predecessors in the field of wireless communication technology.

１．Introduction to Yokosuka Research Park

Yokosuka Research Park (YRP) is a research cluster established in 1997 to unify international standards on mobile phones.  Public research institutions, laboratories of universities as well as leading corporations of Japan and abroad came together at YRP and developed the third generation mobile phone in 2001. In conducting radio wave experiments, interference of radio waves from and to urban areas must be avoided.  This location was selected because of the site conditions as a through area surrounded by hills with favorable access to central Tokyo. One of the most advanced and leading research and development activities in Japan is promoted in an environment rich with nature surrounded by the ocean and greenery.

２．History of Yokosuka

In 1854, Commodore Perry landed on Kurihama Beach in Yokosuka and requested Japan to open the country to the world.  At that time, Perry presented two units of telegraph equipment to the shogunate government and the Emperor.  The intention of these gifts was to show how the world had steadily built telegraph networks as shown in the figure below.

In 1850, the telegraph network crossed the Strait of Dover with undersea cables for the first time in the world. The undersea cables then crossed the Atlantic Ocean in 1866, and it signified the era in which telegraphic communications connected Europe, Asia, South and North America, Africa, Southeast Asia, Australia, and New Zealand.  Japan was not a part of this telegraph network and needed to pour all its efforts into closing this technology gap

In 1889, to respond to the Southward Expansion Policy of Russia, Japan placed orders for battleships with the United Kingdom, and Battleship Mikasa, which is  preserved as Memorial Ship Mikasa in Yokosuka port area, was one of such vessels. 
Shortly after placing these orders, Guglielmo Marconi successfully performed a radio communications experiment in 1895 and gradually extended the range.
Up to that point, the communication method for ships at sea were limited to flag semaphore or blinking lights with a communication range of, at most, 40 kilometers.
The world understood that radio communications was essential for battleships.

Japan therefore negotiated with Marconi to purchase his radio communication equipment, but the price was so outrageous that they had no choice but to engage in their own development. Efforts were made by Senior Researcher Matsushiro of the Electrotechnical Laboratory and Professor Kimura of the former Daini Senior High School (under the prewar education system) which later became Tohoku University, and, in 1897, they successfully completed the first radio experiment off the shore of Shinagawa, Tokyo.

Marconi, at the same time, continued to extend his communication range, and he succeeded in crossing the Strait of Dover, a range of 50km, in 1899.  The Japanese Navy also commenced their radio equipment development with an aim of achieving a communication range of 100 kilometers.  An experiment was conducted in 1900 between Tsudanuma of Chiba Prefecture and Otsu in Yokosuka, a range of 54 kilometers.

However, extending the communication range remained difficult, and it was compounded by the instability of communication itself.  To cope with this situation, the Japanese Navy decided to gather communication engineers at the Naval Arsenal located at Taura (Funakoshi), Yokosuka, in 1902 to engage in radio equipment development.  As a result, the Model 36 radio was created in 1903, the year 36 of Meiji Era, and it achieved a communication range of 1,000 kilometers.  The Navy immediately constructed a radio factory, and the manufacturing work was carried out day and night to equip all their vessels with Model 36 radio.

Yokosuka was selected as the location for the development of radio equipment because it was the center of heavy industries in Japan at the time, with shipbuilding yards and steel mills established in the final days of the shogunate, followed by the establishment of a military port and a weapons factory. It was expected that a variety of knowledge and technologies were available there.

These events led to the telegram transmitted with the Model 36 radio from the merchant cruiser Shinano -Maru at the start of the Battle of Tsushima, on May 27, 1905.  When identifying the Russian Baltic Fleet, a telegram of “Enemy vessel seen” was  sent and relayed by the Battleship Itsukushima  and finally received by the Flagship Mikasa, which succeeded in making the first move in the naval battle.  This became the driving force behind their crushing victory.

Yokosuka thus became the center of heavy industries in Japan and made contributions toward the building of superships.  However, as the trend of the times changed,  in 1975, the gantry crane at Shioiri, which had been indispensable for the town of shipbuilding and had been a landmark of Yokosuka, was removed.

３．Advent of Radio Communications

An Italian inventor, Guglielmo Marconi, succeeded in communicating via radio wave in 1895. Radio communications brought about dramatic progress toward communications between ships, which could not be linked with cables.。

The Model 36 radio communications terminal developed by Matsunosuke Matsushiro and Shunkichi Kimura, which was a driving force behind the victory at the Battle of Tsushima, is currently exhibited in the Memorial Ship Mikasa, preserved in Yokosuka.

４．Beginning of Radio Broadcasts

A rich number of vacuum tube radios were manufactured and popularized in the United States, where radio broadcasting began in 1923.

In 1923, Japan was struck by the Great Kanto Earthquake, which claimed 100,000 lives. The importance of radio broadcasting was reassessed, and the Japan Broadcasting Corporation or NHK (Station JOAK) began radio broadcasting two years later, in 1925. As vacuum tubes were quite expensive at the time, many people listened to radio broadcasts using thin wire crystal detector radio equipment.

５．Development and History of Vacuum Tubes

The vacuum tube makes it possible to transmit and receive radio waves in an efficient and stable manner.

Vacuum tubes evolved significantly in the 1940s, and radio communications with higher frequencies became available. Communications were conducted in high frequency (HF) and medium frequency (MF) at the beginning, but that was expanded to include very high frequency (VHF) and ultra-high frequency (UHF), which is the frequency range available to current mobile phones.

６．Evolutionary History of Radio Communication Equipment

The evolution of the vacuum tube led to more powerful communications equipment, but people suffered economically from material shortage during the World War II. In order to ensure that people could still listen to radio broadcasts, the Government directed manufacture of radios available at low prices. Radios built with “Nami” (meaning “frugal” in Japanese) tubes having three or fewer electrodes were popularized as “Nami San” (Frugal Model 3) and “Nami Yon”(Frugal Model 4) radios.

Amateur radio operations that enabled people to communicate freely with people overseas spread explosively after the war. Manufacturers in the United States that were producing communications equipment for military use also started producing receivers for amateur radio operators. Radio equipment made in Japan for amateur operators that offered high performance at low prices and good design was actively exported.

Advent and Evolution of Semiconductors

Transistors were invented in the United States in 1947, and they rapidly replaced vacuum tubes. Transistors became popular because, unlike vacuum tubes, they had no heater, did not operate at high temperatures, and had semi-permanent life. The technology for stacking up many transistors on top of a crystal, the integrated circuits or “IC” came about soon after, and electronic equipment became increasingly small. This miniaturization also made it possible to create equipment with signals of even higher frequencies.

7. Advent and History of Mobile Phones

The demand for transceivers that made it possible to engage in conversations even while in transit became increasingly high as the world entered a peaceful era and flourished economically. Varieties of transceivers were created, but their biggest shortfall was that they did not link up to a public network.

Car phones started to circulate in Japan in 1979, and it was in 1987 when the phones became light and small enough for people to carry around on their person. There had been four times of generation changes so far. In order to achieve the third generation, to unify the systems around the world, the YRP was established, wherein the forces from Japan as well as overseas gathered.

As a result, the 3rd generation (W-CDMA/CDMA-2000) service started in 2001. The number of people using the Internet on mobile phones has increased rapidly, and we are now in the age of fourth-generation mobile phones, which have the same heart as PCs (personal computers).

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3-4 Hikarino-oka, Yokosuka-City, Kanagawa-Prefecture, 239-0847, Japan