Bangladesh Betar (Bengali: বাংলাদেশ বেতার) or BB is the state-owned radio broadcasting organisation of Bangladesh. It was also known as Radio Bangladesh between 1975 and 1996. Radio transmission in the region now forming Bangladesh started in Dhaka on December 16, 1939. Initially, the station was located in old Dhaka. Later, the station was relocated to Shahbag. It played an important role during the Bangladesh Liberation War of 1971. On March 26, 1971, the broadcasting center of Radio Pakistan was used to transmit a declaration of independence, which was picked up by a Japanese ship in the Chittagong Harbor and retransmitted. During the war, it was known as Shwadhin Bangla Betar Kendro (Independent Bengal Radio Station). Due to heavy shelling, the station had to be relocated several times, and ultimately moved to Calcutta on May 25, from where it would broadcast until the end of the war. On December 6, it was renamed Bangladesh Betar. Today we have 10 radio stations running in Bangladesh. Those are_ * ABC Radio (Bangladesh) * Bangladesh Betar * DHAKA FM 90.4 * Radio 2fun| * Radio Amar
* Radio Dhaka
* Radio Foorti
* Radio Metrowave
* Radio Today
Types of Radio_
FM (Frequency Modulation) Radio
Frequency modulation, FM is widely used for a variety of radio communications applications. FM broadcasts on the VHF bands still provide exceptionally high quality audio, and FM is also used for a variety of forms of two way radio communications, and it is especially useful for mobile radio communications, being used in taxis, and many other forms of vehicle.in view of its widespread use, frequency modulation, FM, is an important form of modulation, despite many forms of digital transmission being used these days. FM, frequency modulation has been in use for many years. However its advantages were not immediately apparent. In the early days of wireless, it was thought that a narrower bandwidth was required to reduce noise and interference. As FM did not perform well under these conditions, AM predominated and FM was not used. However, Edwin Armstrong, an American engineer looked at the use of wideband FM for broadcasting and introduced the idea against the trend of the thinking of the time. Since its first introduction the use of frequency modulation, FM has grown enormously. Now wideband FM is still regarded as a very high quality transmission medium for high quality broadcasting. FM, frequency modulation is also widely used for communications where it is resilient to variations in signal strength.
FM, frequency modulation basics
The most obvious method of applying modulation to a signal is to superimpose the audio signal onto the amplitude of the carrier. However this is by no means the only method which can be employed. It is also possible to vary the frequency of the signal to give frequency modulation or FM. It can be seen below that the frequency of the signal varies as the voltage of the modulating signal changes.
Concept of frequency modulation
The amount by which the signal frequency varies is very important. This is known as the deviation and is normally quoted as the number of kiloHertz deviation. As an example the signal may have a deviation of ±3 kHz. In this case the carrier is made to move up and down by 3 kHz.
Community radio stations are community owned and operated entities that serve either localized geographic communities or communities of interest, such as minorities, religious groups and universities.
Community radio is unique because the stations are run by the communities themselves. They are owned and managed by the people they serve. The management is usually a small team of paid staff with the programming conducted by volunteers.
Unlike commercial stations, community stations are not...