the dawn of amateur radio in the u[1].k.(收音机雏形的诞生)-第23节
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Hague Concerts'。 The original wavelength of 670 metres was later
changed to 1；150 metres。
At that time most of the people who heard these concerts would have
been using headphones and they would not have been very critical about
the quality of the sounds they were hearing compared to the magical
novelty of snatching voices and music apparently out of thin air。 This
historic transmitter can be seen in the museum of the Dutch Postal
Services in the Hague。
The first transmissions of speech and music in England were made
from Chelmsford； Essex； when a 15kW transmitter of the Marconi
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The dawn of amateur radio in the U。K。 and Greece ： a personal view
Company began regular transmissions in February of 1920。
In the summer of 1924 the world's greatest radio companies … British
Marconi； German Telefunken； French Radio Telegraphie and American
R。C。A。 … met in London to discuss transatlantic communications。 The
learned gentlemen all agreed that the Atlantic could only be spanned by
ultra…long waves of 10；000 to 20；000 metres； which would require the use
of hundreds of kilowatts of power and receivers as large as a trunk； not to
speak of antennas more than a mile long。 Dr。 Frank Conrad； who was also
present at the conference； had brought with him a small short wave
receiver less than a foot square。 When he connected it to a curtain rod as
an antenna the faint but clear voices of his assistants in the U。S。A。 were
heard from nearly four thousand miles away。 With this spectacular
demonstration he administered the deathblow to all plans for high power
ultra…long…wavelength transmitters； and from then on the commercial
companies concentrated their efforts on developing equipment for
international communications on the short waves。
With present…day electronic news gathering and world…wide satellite
links； the problems faced by broadcasting organisations fifty years ago
when transmitting programmes which did not originate in a studio were
thought to be very complex。 In the B。B。C。 Handbook for 1928 there was
an article entitled ‘Outside Broadcast Problems' which said；
〃Work outside the studio is often the most difficult that the broadcast
engineer can be asked to undertake； not so much from a technical as from
a practical point of view。 Very often he has to take his apparatus to some
place he has never seen before； set up his amplifiers in most awkward
positions； test his lines to the studio； decide on his microphone placings
and run out the wiring in the space of an hour or so； with little previous
experience to guide him。 It is in fairly echoey halls； theatres and churches
that the majority of outside broadcasts take place。 For example； a sermon
preached in a church would be intelligible probably to the whole of the
congregation。 But to render it intelligibly on a loud…speaker； the
microphone would have to be； say； not more than ten feet from the speaker。
In broadcasting a play from a theatre； when the speakers are moving about；
the only way of dealing with the problem is to use several microphones
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The dawn of amateur radio in the U。K。 and Greece ： a personal view
and a mixing device which enables the engineer to change silently from
one microphone to another； or to combine them in varying proportions。
Some rapid switching may sometimes be necessary。
〃Even with good microphones and amplifiers the engineer in the field
may often experience difficulties with the lines connecting the outside
point to the studio。 The majority of such lines do not transmit the higher
frequencies adequately； especially the longer ones。 The problems become
immense when European simultaneous broadcasts are attempted。
Experiments on the continental wireless link have done no more than
reveal its unreliability。 The undersea telephone line； however； does not
give either good or even intelligible quality of speech if it is longer than a
couple of hundred miles； and it is quite unusable for the transmission of a
musical programme。
〃The B。B。C。 has been the first in the world to exploit Simultaneous
Broadcasting to its fullest advantage for a national system； and thanks to
the co…operation of the Post Office engineers； it is possible to pick up a
programme wherever it may take place within the British Isles and radiate
it simultaneously from all distribution centres。
〃Looking ahead still further and assuming that the wireless will
supplement the wire line link； there is no reason why a simultaneous
broadcast of something of fundamental importance to the whole civilised
world should not take place some time in the future。〃
In a book entitled 〃Radio Goes to War〃 published by Faber & Faber
in 1943； Charles J。 Rolo wrote；
〃Radio went to war on five continents shortly after the Nazi Party
came to power in Germany。 In nine years it has been streamlined from a
crude propaganda bludgeon into the most powerful single instrument of
political warfare the world has ever known。 Spreading with the speed of
light； it carries the human voice seven times round the globe in one second。
When Hitler makes a speech in the Kroll Opera House in Berlin； listeners
in America and the whole world hear his words by short wave even before
his own immediate audience hears them。 Radio speaks in all tongues to all
classes。 All pervasive； it penetrates beyond national frontiers； spans the
walls of censorship that bar the way to the written word； and seeps through
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The dawn of amateur radio in the U。K。 and Greece ： a personal view
the fine net of the Gestapo。 It reaches the illiterate and the informed； the
young and the old； the civilian and the soldier in the front line； the policy
makers and the inarticulate masses。 So great is the importance of radio to…
day that the seizure of a defeated nation's transmitters has become one of
the primary spoils of war。〃
In Greece； broadcasting was started in the northern city of
Thessaloniki （Salonica） by the pioneer of Balkan broadcasting Christos
Tsingeridis； in 1928。 A museum in that city tells the full story of the first
broadcasting station in the whole of the Balkans。
Broadcasting in the capital； Athens； started on March 25th 1938 when
a second…hand 15 kW Telefunken transmitter was put into operation in the
suburb of Liosia。 The centre…fed T antenna was supported between two
pylons of 85 metres （279 feet）。 In 1944 when the German army was
pulling out of Athens they tried to blow the the pylons up but one of them
remained standing at a crazy angle； because one of the explosive charges
had been placed incorrectly。
2。 Avlis ‘The Voice of Hellas'。
The 5th Programme of the Greek broadcasting service （Elliniki
Radiophonia） is transmitted from the short wave transmitting centre at
Avlis； about 70 kilometres north of Athens。 The station was put into
service in 1972 and has two 100KW Marconi short wave transmitters and
a veritable forest of antennas covering 1；100 acres； arranged in three lines
to cover the desired directions； as can be seen on the great circle map。 The
pylons supporting the 6 MHz arrays are truly impressive at 328 feet。 Each
line has eight separate antennas for the 6； 7； 9； 11； 15； 17 and 21 MHz
broadcasting bands。
Each antenna consists of two curtains with a total of 8 horizontal
dipoles。 The dipoles are all fed by open wire feeders which can be
remotely switched to enable radiation in two directions 180 degrees apart。
There are also three curtains for the 11 metre band （26 MHz） which may
be put into service during sunspot cycle 22 if the M。U。F。 allows it。
For transmissions to neighbouring countries like Cyprus； Turkey； the
Balkans and the countries of the Middle East； there are two rotatable log
periodic antennas
