the dawn of amateur radio in the u[1].k.(收音机雏形的诞生)-第4节
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In Italy； a young 22…year…old electrician became interested in
electromagnetic radiation after reading papers by Professor Augusto Righi
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The dawn of amateur radio in the U。K。 and Greece ： a personal view
（1850…1921）。 It was Guglielmo Marconi （1874…1937）； the son of a well…to…
do landowner who lived in Bologna； and who was married to Annie
Jameson of the well known Irish Whiskey family。 Guglielmo； their second
son； had his early education at a private school in Bedford； England； and
later at Livorno and Florence in Italy。 When he read about the experiments
of Heinrich Hertz and about Popov's suggestion； he saw the possibility of
using these waves as a means of signaling。 His first transmitter； shown in
the accompanying photograph； did not radiate very far。 When he folded
the metal plate into a cylinder and placed it on a pole 30 feet above the
induction coil and connected to it by a vertical wire； he was able to detect
the radiation nearly two kilometres away。 Marconi realised that his
signaling system would be most useful to shipping； and in those days
England possessed the world's greatest navy and the world's biggest
merchant fleet。
The Italian government was not interested in young Marconi's work；
so after a family conference he was brought to London by his mother； who
had influential relatives there。 Not only did they finance his early
experiments but they also put him in touch with the right sort of people。
One of these was Alan A。 Campbell Swinton who became the first
President of the Radio Society of London （now the R。S。G。B。） many years
later； in 1913。 Campbell Swinton introduced the young Italian to William
Preece； then Engineer…in…Chief of the British Post Office。 Preece had
already been investigating various methods of 'induction' telegraphy。
In a book entitled Wireless Telegraphy published in 1908； William
J。White of the Engineer…in…Chief's department at the G。P。O。 wrote；
〃The work of Sir （then Mr） William Preece； important though it was；
did not attract the attention of the public to the extent that might have been
expected。 This was due to the fact that no sooner had he demonstrated a
method of wireless telegraphy which was a commercial possibility than
his system was superseded by another； and a better one； brought to
England by Mr Guglielmo Marconi in 1896。 The possibilities of Mr
Marconi's system were at once recognised by Mr William Preece。 The
experience of the elder and the genius of the younger man； who must be
given the credit of having devised the first practical system for wireless
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The dawn of amateur radio in the U。K。 and Greece ： a personal view
telegraphy； combined to turn apparently disastrous failures into success；
and now （in 1908）； wireless telegraphy has become； in less than a decade；
part and parcel of commercial and national life。〃
The world's first patent for wireless telegraphy was awarded to
Marconi on the 2nd June 1896。 In it he stated that 〃electrical action can be
transmitted through the earth； air or water； by means of oscillations of high
frequency。〃 In the first public demonstration of his equipment Marconi
spanned the 365 metres between the G。P。O。 and Victoria street。 Later； on
Salisbury Plain； in March 1897； his signals were detected over 7
kilometres away。 On the 11th & 18th May 1897 messages were first
exchanged over water。 On the 27th of March 1899； during naval
manoeuvres； Marconi bridged the English Channel for the first time； a
distance of about 140 kilometres。 His transatlantic triumph came on the
12th December 1901 when the morse letter 'S' was transmitted from
Poldhu； in Cornwall and received by Marconi himself at St。 John's；
Newfoundland； who recorded the historic event in his pocket book simply
〃Sigs at 12。20； 1。10 & 2。20〃。
The operation of Marconi's transmitter was itself quite spectacular。 To
produce the oscillations he employed the oscillator designed by Augusto
Righi。 Depressing the key closed the circuit and brought the inductor coil
into action。 Vivid sparks occurred between the balls of the oscillator； to the
accompaniment of a succession of sharp cracks； like the reports of a pistol；
and some energy was sent off the square metal plate in the form of trains
of electromagnetic waves； which radiated out in all directions。 But the
energy occupied a very large bandwidth and the receivers of that period
could not separate two transmissions。 William J。White of the Post Office
wrote in 1908； 〃The chief objection which has been raised against modern
wireless telegraphy is its want of secrecy。 With a transmitter sending out
waves in all directions； it is possible for unscrupulous persons to receive
the messages and make an improper use of them。 This form of 'scientific
hooliganism' has； in fact； become somewhat notorious。 When two or three
transmitters are each sending out their electromagnetic waves； the result；
naturally； is utter confusion。〃 White added that the British Postal
Administration was refusing to grant licences for more than one system in
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the same area； in spite of the fact that there had been some 'alleged'
solutions of the problem。 The phenomenon of resonance was known and
Dr （later Sir Oliver） Lodge had taken out various patents between 1889
and 1898 in connection with receivers。 Marconi and his assistants
ultimately solved the problem by modifying Lodge's syntonic Leyden jar
tuned circuit。 They added a tapped inductance in the aerial circuit of the
transmitter and used variable capacitors instead of fixed ones。 This was
probably the most significant modification made in the development of
wireless telegraphy。 （In Greek the word syntonismos 'to bring to equal
tone' is used for 'tuning'。）
Apart from the patents taken out by Sir Oliver Lodge and Dr
Alexander Muirhead； in 1897； patents were taken out in Germany by
Professor Braun of Strasbourg； who was joined by Professor Slaby and
Count D'Arco in 1903 to form the Telefunken company； and in the U。S。A。
by Dr Lee De Forest of the American De Forest Wireless Telegraph
Company who was the first to use a high A。C。 voltage of 20；000 volts to
obtain the necessary high…potential discharges； thus dispensing with the
induction coil。 Again in the U。S。A。； Professor R。O。Fessenden was
responsible for the design of new types of transmitting and receiving
apparatus。
During this period Marconi had resisted all offers by financiers to
acquire his patents。 In July 1897 he entrusted his cousin Jameson Davis to
form The Wireless Telegraph & Signal Company Ltd which soon became
Marconi's Wireless Telegraph Co。； and ultimately the Marconi Company。
William Preece of the Post Office detached one of his assistants；
George S。 Kemp； to help Marconi。 Kemp was destined to become his
right…hand man and served Marconi faithfully throughout his life。 By
today's standards； Marconi can be said to have been a highly successful
entrepreneur。 He had the great knack of selecting the right man for the job；
and inspired deep loyalty in his staff。 He regarded himself as an 'amateur'
and often paid tribute to the work of radio experimenters。
（Most of the above passages are quoted from 'A History of the
Marconi Company' by W。J。Baker； published by Methuen & Co Ltd。
reprinted in 1979。）
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