Radio Broadcasting

Posted on November 25, 2009 by greenstoneradio.
Categories: Radio, Radio broadcasting.

Radio broadcasting is a means of transmitting audio signals via the air as radio waves. These radio waves travel from a transmitter to an antenna and from there are sent to a receiving device to be interpreted.

Radio waves are a form of electromagnetic radiation with a very high frequency. They are invisible to the human eye and sit above infrared waves in the electromagnetic spectrum. They provide a relatively simple and inexpensive way to transmit signals to wide audiences.

Whilst radio stations are commonly known as public systems there are also many stations that exist for non-broadcast purposes, such as base stations used by the emergency services, dispatch stations used by truck and taxi services, amateur radio stations and emergency broadcast systems.

The two primary types of radio station are AM and FM stations.

AM radio stations were the earliest wide-scale broadcasting systems to be developed. AM stations use amplitude modulation to change the radio carrier signal so that it can be interpreted by the listener.

A key advantage of AM radio stations is that the signal being transmitted is relatively unsophisticated, and as such it can be detected and decoded with basic equipment. However, this simple signal is vulnerable to interference by bad weather.

FM radio stations use frequency modulation to alter the radio carrier signal and broadcast a message. FM stations broadcast in the VHF (Very High Frequency) range of airwaves in the frequency range of 88 MHz to 108 MHz.

FM radio was invented in the 1930s by Edwin Armstrong with the sole purpose of solving the interference problems inherent in AM radio. FM radio is almost immune to this interference and has also achieved greater signal clarity by spacing radio stations further apart than AM stations.

The emergence of the Internet has prompted radio stations to broadcast online. Since the 1990s radio stations have been broadcasting on the Internet where they do not suffer from the licensing restrictions applied to other stations, and there is no need to setup air transmission equipment to be able to broadcast to the world.

Radio technology

Posted on October 3, 2009 by greenstoneradio.
Categories: Radio, radio technology.

Radio communication is a widely used form of communication that takes advantages of the characteristics of radio waves to transfer messages across wide distances. Radio messages are sent from a radio transmitter and are received by an antenna which sends them to a receiving device.
The most popular usage of radio communications today is radio broadcasting – an audio broadcasting service widely used by listeners for music and broadcast conversations. Other types of communications sent via radio waves include Morse code, and more recently DAB, or Digital Audio Broadcasting.

The two most common forms of radio broadcast include AM and FM; the two techniques used to broadcast commercial radio stations. Radio waves can also be sent and received via citizens band radio (CB radio) or even transmitted via satellites.

The fundamental idea behind broadcasting radio communications is to transmit a carrier signal which can be received by a correctly tuned receiver and then to vary that carrier signal according to the message you want to send.

AM Radio

A.M. stands for amplitude modulation and was the original method used to broadcast radio stations. It involves changing the amplitude of the carrier signal to send a message. It is a very simple system that does not require a lot of expensive equipment to receive a signal.

AM radio signals are subject to interference by EMI, or Electromagnetic interference. This is most notable to listeners during weather events such as lightning storms.

FM Radio

F.M. stands for frequency modulation and involves varying the frequency of the carrier signal to transmit a signal. This technique is used in the VHF, or “Very High Frequency”, range of airwaves.

FM Radio allows broadcasts to be made with much less interference than AM signals, and by spacing FM stations further apart they are less likely to interfere with each other. The range of an FM broadcast is not as great as an AM broadcast so they are more suitable for local radio stations.

Radio Information

Posted on September 7, 2009 by greenstoneradio.
Categories: Radio.

Green Stone Radio was a women’s radio show run from New York. With high profile support the radio show broadcast on 7 affiliate radio shows and provided women focused humour and information.

The station closed in 2008 after operating for less than a year.