Brief History of Telecommunication part 4
by matt_bird on 08-12-2011 15:29 - last edited on 08-12-2011 15:56
A Brief History Telecommunications
part 4
Wireless and Carphones
Now that the last three articles have given us the background about the phone networks, this time we are going to look specifically at the origins of mobile services.
As we already know Alexander Graham Bell was the first to make a truly wireless call with his "Photophone" in 1880 which used a beam of light to carry a call 250ft between buildings. Bell himself considered this his most important invention and he wasn't wrong, this was an early version of laser (as it were) and more importantly the first ever wireless call, so it was the ground zero in terms of the mobile phones that we all depend on so much nowadays.
The most influential early discoveries about wireless transmission were the theory put forward by Michael Faraday, of Faraday's Cage fame, around the 1870's before the end of his life, and the actual demonstration of electromagnetic waves by Heinrich Hertz in 1888. There was no immediate use of this technology but it was soon expanded upon by pioneers like Nikola Tesla who demonstrated wireless energy transmission in 1891. Six years later Tesla filed the first patent for Radio and in 1898 he gave a demonstration of a radio-controlled boat to the US military who he believed would want to use radio-control torpedoes. Tesla also patented the spark plug for internal combustion engines that same year.
Tesla in his lab, Colorado Springs. 1900
After Hertz's death in 1894 his earlier work was republished and this inspired the Italian Guglielmo Marconi, who at the age of 21 in 1896 moved to London and gained the support of the British General Post Office under their Chief Electrical Engineer, William Preece. Marconi had already in Italy been able to broadcast morse code over 1 & 1/2 miles and with the Post Office backing was soon working on Salisbury Plain and able to transmit morse over 4 miles. Later over the summer of 1897 Marconi sent the first ever wireless communication over open sea and was soon transmitting 10 miles from Lavernock Point in South Wales to Brean Down Fort on the Somerset coast.
Around the turn of the century Marconi had his sights set on trans-atlantic broadcast to compete with the telegraph cables that had been working for about 40 years and by February 1902 he was able to transmit from Poldhu in Cornwall to the SS Philadelphia 2100 miles away. In December of 1902 the first true trans-atlantic radio message was received in Nova Scotia, Canada from the Poldhu base. The following year from South Wellfleet, Massachusetts the first American sent trans-atlantic message was greetings from Theodore Roosevelt, the President to King Edward VII in the UK.
In 1899 Marconi started a factory in Chelmsford, Essex to make his radio equipment and it was from here in 1920 that the first British radio entertainment programs, featuring Dame Nellie Melba, were broadcast from the two 450ft masts at the factory / studio. The peak of Marconi's career was arguably in 1909 when he shared the Noble Prize for Physics with Karl Braun the inventor of the cathode ray tube (television) for their work in radio.
Marconi's New St factory Chelmsford 1920
Whilst Marconi was behind the first British radio broadcasts they were in fact pioneered in the US by the National Electric Signaling Company, funded by two Pennsylvanian businessmen Hay Walker Jr and Thomas H Given to back the research of inventor Reginald Fessenden. Using his own equipment and in conjunction with General Electric, these broadcasts were made around Xmas and New Year 1906/7.
Fessenden was a great inventor but a far less successful businessman, with Walker and Given he tried & failed to sell NESCO to larger companies like AT&T and this failure led him to start up the Fessenden Wireless Company of Canada. This in turn led to his dismissal from NESCO in 1912 and was followed by long legal proceedings which were finally settled in 1928 by the then owners of NESCO's assets and patents the Radio Corporation of America. In these years NESCO had been in receivership, emerged as the International Radio Telegraph Company and had been sold to Westinghouse before coming under the control of RCA.
Fessenden's Rotary Gap transmitter 1906
Fessenden had also demonstrated "ship to shore" radio communication and this was taken up by the US military and was developed and used throughout the 2nd World War. The first civilian radio telephony services came about soon after the war. The first car call was made using Bell System's Mobile Telephone Service in June 1956 using equipment that weighed in at nearly 40kg over lines provided by AT&T using operators to connect the calls. This system used the one-way "push to talk" button (like walkie talkies) and the service was charged at $30 a month and 30 to 40 cents per minute for local calls, which equates to roughly $340 a month with calls costing $3.50 to $4.50 a minute.
In Europe the worlds first semi automatic car phones system, Mobile System A (MTA) was launched in Sweden in 1956 based on old vacuum tubes and relays, it weighed in at 40kg. This was followed in 1962 with MTB which used transistors and a push-button telephone to cut the weight down to 10kg. MTB was replaced in 1971 by MTD which was the first real commercial success with several competing brands selling the kit. MTD lasted until 1987 and achieved a customer base of near 20,000 users calling through 700 operators across Sweden, Denmark and Norway. It was superceeded by NMT, Nordic Mobile Telecom and their fully automatic calling system.
In the UK the first car based calling system was launched in 1959 in Lancashire and expanded to London in 1965, coinciding with the opening of the Post Office Tower.
System 2 the 9 channel Radiophone
By the early 1970's there were 3 licenced UK suppliers of mobile equipment for vehicles, Marconi, Pye and Storno. Storno also produced a battery operated version for pedestrian use. By 1983 and system 4 there was no longer a need for operators to connect the calls as Public Radio Telephone System 4 (PRT4) used direct dial technology and full duplex (2 way) transmission which removed the need for the "push to talk" button.
PRT 4
The PRT4 system was overtaken in 1985 by the mobile phone systems we are now familiar with, ie 1g followed by 2g in 1991 and 3g in 1999 which we have covered in the previous articles.
To follow on from this article there will be a more focused look at car based calling technology with another series of articles written by a new blogger stan.
I must also thank paul_gray and adsb for pointing me in the right direction for this article. Cheers guys.
Thank you all for reading, there will be more soon.
Matt
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