2003 / 10   Digital Terrestrial Radio test transmission started, employing the unused TV channel 7 VHF bandwidth. Programs are transmitted by the Digital Radio Promotion Association (DRP), a licensed broadcasting corporation run jointly by NHK, several commercial radio stations in Tokyo and Osaka, and some new entrants into the digital radio market. 2003 / 12   Digital terrestrial television broadcasting started in three major cities of Tokyo, Osaka, Nagoya.  Terrestrial broadcasting has been the mainstream format of television broadcasting in Japan since its introduction nearly half a century ago, and accordingly, the viewing public has come to enjoy its widespread availability.  Although Japan's land area is only 1/25 that of the United States, the country's mountainous topography and numerous isolated islands have required twice the number of relay stations, each of which must use a different frequency to avoid interference. The resulting channel congestion is said to be 50 times worse than that of the U.S., leaving insufficient frequencies for the introduction of digital terrestrial broadcasting. In order to secure enough frequencies for digital broadcasting, NHK is spearheading a multi-year, nationwide project to change the current allocation of TV channels through employing a process known as "analog-analog conversion." This process is carried out jointly in cooperation with governmental agencies, NHK, commercial broadcasters and equipment manufacturers. This conversion will proceed at a measured pace to ensure the understanding and acceptance of the viewing public, with the aim of facilitating digital terrestrial broadcasting of local programs attuned to regional needs.  Compared with digital satellite broadcasting, which provides uniform programming throughout the country, digital terrestrial broadcasting is better suited for local broadcasting and will enable more programming focused on regional needs. The introduction of digital terrestrial broadcasting in Japan will provide the viewing public with numerous advantages, including access to stable, clear reception and high-quality mobile reception via cellular phones and other devices.     2004 / 9  Multi-channel Service started on the Digital Educational TV channel.  With digital terrestrial broadcasting, viewers can enjoy two to three standard-definition (SD) programs at the same time on a single HDTV channel.  The Digital Educational TV channel started offering a full-fledged multi-channel service in September 2004, offering three SD channels on one Hi-Vision channel. ETV1 is a simulcast of regular analog Educational TV channel. ETV2 and ETV3 are dedicated to various programs on welfare, science, hobbies, the game of go and shogi, and foreign language lessons.     2006 / 4  Digital terrestrial broadcasting for mobile reception will start in April 2006. This new service called “One Seg” uses one of the 13 segments which compose bandwidth of one channel.  Thanks to digital technology, it is possible to receive remarkably clear images, sound and data broadcasting on mobile phones anytime, anywhere even while on the go.  “One Seg” will start in 29 prefectures in April 2006, and will be introduced to other areas in phases.     2007  Home Server-based Broadcasting will start in 2007.  This is a new form of broadcasting and internet connections with a large-capacity data storage system at home. Viewers can watch programs whenever they like, picking up favorite sections and using various control functions to suit their needs. NHK is working with commercial broadcasters and receiver manufacturers to launch the service.  With home server-based broadcasting, the audience will be able to “read” as well as watch each program, as text data (comments by the cast, etc.) will be provided with the broadcast.