02/01/2017. Student ID: Product Logic Report MANG1018. Word Count: 1644

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1 02/01/2017 Student ID: Product Logic Report MANG1018 Word Count: 1644

2 Radio is the transmitting and detecting electromagnetic (EM) waves carrying sound for communication and entertainment purposes. Radio technology invention began in the late 1880 s, with Maxwell and Hertz forming the basis of the technology. Numerous inventors contributed to radio s development in the succeeding decades. The technology began with Maxwell mathematically proving the existence of EM waves (Fleisch, 2008). Then in 1887, Heinrich Hertz physically demonstrated EM waves existed with spark gap equipment. Radio adheres to Arthur s interpretation of technological development. Technology builds from harnessing phenomena largely uncovered by science (Arthur, 2009, p.65). In this case, harnessing EM waves using spark gap equipment. These technologies develop knowledge and help uncover yet further phenomena such as the superheterodyne receiver and transistor receiver. Oliver Lodge contributed to popularising the coherer a technology initially used to detect radio waves - in Guglielmo Marconi foresaw radio technology s potential purpose: to communicate over great distances. After many experiments, he enhanced the distance of signal detection. He developed coherer technology, before magnetic detectors replaced coherers - which he used during the first transatlantic wireless transmission. Despite magnetic detectors later being surpassed by vacuum tubes, the technology was used on ships as it was reliable and insensitive to vibration. Continual technological developments resulted in the invention of; crystal sets, the superheterodyne radio and, the transistor radio. A new radio technology - the superheterodyne radio - surpassed crystal sets and tuned frequency receivers (TRF) to meet consumer needs of better gain and selectivity. The superheterodyne receiver was manufactured by General Electric and marketed by RCA (Jerome S. Berg, 2013). The receiver could be purchased as a complete set or a radio kit for the consumer to create (Time Inc, 1963). The superheterodyne receiver was invented in It enabled the user to select from different stations by using a variable frequency oscillator. The receiver s frequency mixer changed incoming radio frequency to an intermediate frequency (IF). A demodulator extracted audio, from the signal, which was amplified by an audio amplifier (Radio-Electronics, 2013). IF was a frequency conceived by Edwin Armstrong in 1918, solving the short-wave amplification problem (Armstrong, 2006). The superheterodyne radio and its principle were both invented by Armstrong. The principle behind the receiver was to reduce incoming frequency to efficiently amplify it allowing for greater levels of gain. In the early 1920s there were only a few accessible stations, so the superior performance of the superheterodyne was not required. Despite being accepted by the military, the superheterodyne radio was initially unpopular for commercial broadcasting due to price and the skill required to operate it. Instead easier to operate and cheaper to purchase TRFs were used. But as vacuum tube technology developed TRF s cost advantage was lost. More stations came on air as the decade progressed so there was a need, especially in America, for the selectivity and gain of the superheterodyne radio. 600 radio stations sprung up by 1922 in America alone. Armstrong s receiver started to be widely used for broadcasting local information and entertainment. Domestic use of the receiver resulted in development. Originally the radio set was difficult to use. Ganged tuning capacitors were introduced allowing for the local oscillator and radio frequency to be controlled by a single remote (Chattopadhyay, 2006). Other refinements, like developments in valve technology, contributed to making the superheterodyne easier to use. Originally all valves were directly heated. The introduction of indirectly heated valves enabled an alternating heat supply to be used, allowing required conditions 1

3 to be met irrespective of the filaments being connected in series or parallel (Electronics Notes, 2016). In 1920 there were broadcasts, by the Marconi Company, founding radio technology as a means of broadcasting entertainment and news. These initial broadcasts had an enormous social impact. By 1922 the British Broadcasting Corporation (BBC) was formed and took over the London station - established by the Marconi Company. It offered a coverage of 40 miles. In 1934 Edwin Armstrong, conceived Frequency Modulation (FM) and later convinced people of its superiority, eventually leading to the BBC offering its wideband FM service in The superheterodyne radio improved the technology and it became a mass market product (Mollgaard, 2011). The technology s appeal was demonstrated with the growing number of radio stations. Each station was initially specialised offering an exclusive genre of music or entertainment. Radio began to provide a sense of community as stations diversified. Stations began to broadcast; popular music, sport event commentary, fictional stories, news updates and weather forecasts/warnings. Each social and ethnic group could tune into stations that appealed to their diverse interests. Families also relied on radio to deliver evening entertainment. Radio was commonly seen as a public service before the late 1920 s. Radio DJs and announcers generally worked without profit. As the decade progressed stations began to sell advertising time to local companies to generate revenue. This changed the medium s public service image. Legislation also influenced the technology s use. The government were slow to regulate the airwaves. Laws, like The Radio Act of 1912 and later 1927, eventually asserted governance over broadcasting (Keith, 2012). The superheterodyne radio enabled stations to prosper from advertisements as the radio market become saturated. Its performance allowed listeners to tune into the plethora of stations that became available during the age. Once the superheterodyne radio was well established it was the only radio topology used. The radio was developed into double and even triple superheterodyne radios that had correspondingly high levels of performance. Regardless of the replacement of the receiver Armstrong s principle is still in use as modern radio receivers still use the superheterodyne principle. The next significant development in radio technology was the emergence of the transistor radio. John Bardeen, Walter Brattain, and William Shockley invented the transistor while working for Bell Labs in 1947 (Bathgate, 2012). This electronic component enabled radio signals to be amplified while using smaller circuits and batteries. This development illustrates that, a technology improves as better subparts are swapped into its assemblies. (Arthur, 2009, p.134). However, the technology was initially expensive, restricting its use. Radio manufactures were content with vacuum tubes, and their profitability, having used the technology as an amplifier for years. Texas Instruments proved transistors, and products that used them, could be mass produced and so were affordable. Soon after General Electric and Emerson, among other companies, began to sell technologies with transistors. Transistor radio components, like the antenna and battery, were manufactured separately, usually at different firms around the country. Radio components were then purchased by manufacturing companies, which hand assembled each radio. This supports Arthur s claim that each technology has a recursive nature they consist of technologies within technologies (Arthur, 2009, p.38). Each component was attached to the circuit board by hand. The circuit board was dipped in a 2

4 solder bath soldering each component to the circuit board. After passing a series of electrical tests the speaker was attached and the radio was placed in its case. The Regency TR-1 was the first commercially produced transistor radio, selling 100,000 units by the end of 1955 (Glover, 1995). By the early 1960s transistor radios were the most popular electronic communication device in history. Although transistor radios gained acceptance as broadcast sets, their introduction was slower in the professional market. Early receivers, that used valves, performed poorly but as semiconductor technology surpassed valve technology transistors performance improved. This enabled advancement in radio size and weight. Further developments in semiconductor technology led to the introduction of the integrated circuit, enabling further radio receiver technology development. The Regency TR-1 weighed only 340 grams. It s compact dimensions (length five inches, width three inches and thickness 1.25 inches) and transistor enabled the radio to be pocket sized (Regal, 2005). The radio s size revolutionised media consumption, users could listen to music, hear breaking news, and weather forecasts anywhere on the go. This portability provided radio users with previously unimagined convenience. The TR-1 ignited an international demand for portable electronics, forming the DNA of numerous technologies used today like smartphones. Transistor radios succeeded due to a combination of social forces; a young population with abundant disposable income and, rising interest in rock n roll music. Transistor radios were more elaborately designed as suppliers tried to differentiate themselves from each other. This was caused by extensive competition, and new competitors entering the radio receiver market. Eventually, transistor radios doubled as novelty items and were used as a means of advertisement by companies. Since 1980, portable radio popularity deteriorated due to portable audio players that allowed users to listen to their own collection of music and tune into radio stations. Portable cassette players like the Sony Walkman and later portable CD players reduced transistor radio use. Invention of multi-purpose technologies like the ipod, smartphone, and laptop enable users to access desired radio frequencies without a dedicated radio via digital radio. Radio receiver technology has also been replaced with intuitive music services like SoundCloud and Spotify, that enable users to listen to their collection of music via an internet connection. This technology has changed music consumption. Earlier technologies like crystal sets and superheterodyne receivers encouraged communal media consumption. Consumption has become a private experience, for most, due to the technological developments mentioned and the introduction of other technology like headphones. From Marconi s experiments to the use of superheterodyne radio and the popularisation of the transistor receiver, radio technology s purpose undertook significant change. Radio technology s initial purpose was to enable long range communication for cities and even countries to connect. With station numbers rising, radio being used domestically, and the introduction of the superheterodyne receiver the purpose of radio shifted. It became a medium providing local relevant information to listeners, and began to develop into a source of entertainment. Radio had developed into a multi-purpose medium, by the introduction of transistor radio, which paved the way for future portable audio technology. Despite radio s replacement, radio technology remains in the modern day in the shape of digital radio. 3

5 Reference List: Arthur, W.B. (2009) The Nature of Technology. London: Penguin. Bathgate, G. (2012) Voices from the Ether: The History of Radio. North Carolina: lulu publishers. Available from: ary_r&cad=0#v=onepage&q&f=false [Accessed 3 January 2017]. Chattopadhyay, D. and Rakshit, P.C. (2006) Electronics (Fundamentals and Applications). New Delhi: New Age International Publishers. Available from: _r&cad=0#v=onepage&q&f=false [Accessed 2 January 2017]. E. H. Armstrong (2006) Proceedings of the Institute of Radio Engineers. A New System of Short Wave Amplification, 9 (1), Electronics Notes (2016) History of Vacuum Tube / Thermionic Valve. Available from: [Accessed 4 January 2017] Fleisch, D. (2008) A Student's Guide to Maxwell's Equations. Cambridge: Cambridge University Press. Available from: [Accessed 3 January 2017]. Glover, C. (1995) Bulletin of The British Vintage Wireless Society. Wireless, 20 (6) Hand, R.J. and Traynor, M. (2012) Radio in Small Nations: Production, Programmes, Audiences. Wales: University of Wales Press. Available from: ary_r&cad=0#v=onepage&q&f=false [Accessed 4 January 2017] Jerome S. Berg (2013) The Early Shortwave Stations: A Broadcasting history through North Carolina: McFarland. Available from: st+superheterodyne+receivers+%22manufactured%22&source=bl&ots=qblvbj2qrc&sig=wax- 7JYvxdztVhff7vt6ArkGsLQ&hl=en&sa=X&ved=0ahUKEwidiNTzn6bRAhVqDcAKHaYzAS4Q6AEIGjAA#v= onepage&q=built&f=false [Accessed 3 January 2017]. Keith, C.M. (2012) The Radio Station: Broadcast, Satellite, and Internet. Abingdon (UK): Taylor & Francis. Available from: y_r&cad=0#v=onepage&q&f=false [Accessed 3 January 2017]. Mollgaard, M. (2011) Radio and Society: New Thinking for an Old Medium. Cambridge: Cambridge Scholars Publishing. Available from: ry_r&cad=0#v=onepage&q&f=false [Accessed 2 January 2017]. Radio-Electronics (2013) Superheterodyne Radio Receiver. Available from: [Accessed 2 January 2017] 4

6 Regal, B. (2005) Radio: The Life Story of a Technology. California: Greenwood Publishing Group. Available from: ry_r&cad=0#v=onepage&q&f=false [Accessed on 4 January 2017]. Time Inc (1963) Life. November 22, 55 (21),

Postcard Radio Project

APPLIE TEHNOLOGY & ENGINEERING Postcard Radio Project Name: ate: Grade: Section: Postcard Radio Project ESIGN HALLENGE >> esign and build a simple radio that will receive an AM signal through the air without