Alexander Popov – a Great Contributor to the
Development of Wireless Communication
Anna P. Konstantinova
Student of the
St Petersburg State Electrotechnical University “LETI”
IEEE Student Member
Co-author: Dr. Larisa I. Zolotinkina
Memorial Museum of A. Popov in St Petersburg State Electrotechnical University Director
Abstract “This paper is devoted to the life
and scientific activities of Alexander
Popov who is regarded in Russia as the
inventor of radio communication. It
touches upon the most important
contributions made by Popov to the
development of electrical and radio
engineering. In addition, it presents a
brief review of the collection of the
Memorial Museum of A.Popov in LETI
(The St Petersburg State Electrotechnical
University).”
I. Introduction
Looking back at the most amazing
discoveries and inventions of the 20th
century we, the people of the 21st century,
can’t help feeling admiration of those of
them, which had profound influence on the
further development of mankind.
One of the most significant achievements
of the very end of the 19th century and the
beginning of the 20th century was the birth
of wireless communication.
This important event is surely a
milestone in the formation of the new
information environment and consequently
in the formation of modern lifestyles.
Nowadays it is impossible to imagine any
successful cooperation, cultural or human
contacts without such a considerable
technological breakthrough as the
transmission of electromagnetic signals, that
is “inventing” wireless.
It is absolutely obvious that our ability to
communicate with each other easily has
made our life more enjoyable and has
allowed us to exchange information
including information on science and
technology.
We have got this wonderful opportunity
due to joint efforts of many prominent
scientists. Among the great pioneers of
wireless are such outstanding scientists as
Mickle Faradey, James Maxwell, Henri
Hertz, Edouard Branly, Nickolas Tesla,
Oliver Lodge etc.
It is broadly agreed that the works of
Mickle Faraday, Maxwell, Henry Hertz
were vital in laying the foundation for
practical application of electromagnetic
waves.
Oliver Lodge provided independently a
number of the essential elements that
enabled to develop a system of wireless
communication.
In most European countries Guglielmo
Marconi is generally recognized as the first
to exploit the practical application of
electromagnetic waves. While in Russia
Alexander Popov is regarded as the inventor
of radio communication.
1
II. Popov’s biography and scientific
activities
Alexander S. Popov was born on the 16th
of March in 1859 in Tourinskii Mining
Village in the Urals where his father was a
priest. He received a free seminary
education to encourage him to follow his
father’s profession.
After graduating from the seminary in
Perm he didn’t continue his clerical
education for he had become interested
instead in physics, mathematics and
engineering. He was admitted to the Faculty
of Physics and Mathematics of St Petersburg
University in 1877. While still a student
Alexander Popov worked as a guide at the
first Electrical Engineering exhibition in
1880 and an assistant to a professor of
physics. In 1881 he began to work at the
Electrotechnik workshop which ran the first
electric power stations in Russia and the first
electric lighting installations using arc
lamps.
Thus Alexander Popov graduated from
the University being not only an educated
physicist, but also an experienced electrical
engineer.
After graduating the St Petersburg
University where he was awarded a higher
degree upon completion of his dissertation,
Alexander Popov was recommended by the
Scientific Counsel to remain at the
University in order to prepare for an
academic career. However in summer of
1883 Popov was offered the post of a
lecturer and the head of the physical
laboratory in Kronstadt where he could do
experimental research in electrical
engineering.
In 1883 he started to teach at the
Kronstadt Torpedo School, one of the most
prestigious Higher Naval Engineering
Schools in Russia at that time which trained
naval specialists in all branches of electrical
engineering.
In 1890 Alexander Popov began teaching
in the Marine Engineering School which
belonged to Naval Department. He was
obliged to make a signed statement on non-
divulgence of military secrets which later
prevented him from getting a patent for his
invention. He taught electrical engineering,
mathematics and physics. Popov also
conducted laboratory sessions in electricity
and magnetism as well as on electrical
machines and motors. It was in Kronstadt
that he realized quite well the Russian
navy’s acute need for wireless
communication.
The excellent equipment of the physics
laboratory enabled Alexander Popov to run
many physical experiments. He stayed at
Kronstadt until 1901.
At the beginning of 1895, Popov re-ran
the experiments of Henry Hertz and Oliver
Lodge and refined the Branly-Lodge
coherer. He ensured automatic sensitivity
restoration of a coherer after receiving a
signal by its shaking with a bell clapper.
Besides, Popov added a receiving antenna
and a relay to his scheme. As a result Popov
designed the wireless telegraphy working
receiver which was both reliable and stable.
Using this apparatus A. Popov demonstrated
that it was possible to transmit short,
continuous signals (applying an improved
Hertz oscillator as the transmitter) over a
distance up to 64 meters.
In a public lecture “On the Relation of
Metallic Powders to Electrical Oscillations”
presented on the 7
th
of May 1895 to the
Physical Section of the Russian Physical and
Chemical Society in St Petersburg,
Alexander Popov demonstrated the
reception of electromagnetic signals for the
first time. An account of this meeting was
subsequently published in the August 1895
issue of the Russian Physical Chemical
Society Journal which was widely known in
the international scientific community.
The newspaper “Kronstadtskiy vestnik”
2
reported:
“Honorable Prof Popov… combined a
special portable device responding to
electric oscillation by a ringing bell, the
device being sensitive to the Herz waves at a
distance of up to 30 sazhens.
Last Tuesday Prof. Popov reported on his
experiments to the Physical Department of
the Russian Physical and Chemical Society
and his report was met with a great interest
and enthusiasm. These experiments were
induced by a theoretical possibility of
wireless signaling, like it is with optical
telegraph but using the electric beams.”
In January 1896 the same journal carried
an article by A.Popov together with a
detailed circuit diagram of the wireless
apparatus which was called “an Apparatus
for Detecting and Recording Electrical
Oscillations”. (See Popov’s apparatus
scheme in the reference №1 in the
Appendix)
The article concluded with the following
words: “… I hope that my apparatus, when
perfected, may be used for the transmission
of signals over a distance with the help of
rapid electrical oscillations as soon as a
source of such vibrations with sufficient
energy is discovered”.
In the summer of 1895 A. Popov had
adapted his instrument for the automatic
registration of atmospheric oscillatory
discharges; it was later called a lightning
recorder. Experiments with it led A. Popov
to study the possible influence of
atmospheric disturbances on the
transmission of signals. Popov’s lightning
recorder was in wide use all over the world.
A. Popov went on to perfect his device
for wireless communication enhancing the
sensitivity of the apparatus and increasing
the distance over which the signals could be
carried. By the beginning of 1896 A. Popov
had substantially improved his receiver and
had obtained important results in
transmitting and receiving signals. He
demonstrated his apparatus at the meeting of
the scientific society in March 1896. The
distance between the transmitter and the
receiver was 250 meters. Apparently A.
Popov had signaled “Heinrich Hertz” in
Morse using the telegraphy apparatus and
the words had been written down on a
blackboard by professor Petruchevsky – the
president of the Russian Physical and
Chemical Society. Before the summer of
1896 the improved apparatus was described
in a total of 11 publications which made this
invention accessible for a practical use.
In May 1897 the signaling system using
electromagnetic waves was well tested at
Navy in the Gulf of Finland at the distance
over 600 meters.
III.
Practical Application of Popov’s
Experimental Results
A. Popov took an active part in bringing
wireless telegraphy apparatus into practical
application. The first of them were
manufactured according to his instructions
by E. Diucretet, a French engineer and
businessman in 1899 in France. Both
Russian and French Navy were equipped
with the wireless telegraphy apparatus. Its
production in France started under the name
Popov-Diucretet.
In 1899 A. Popov developed a wireless
receiver based on the detector effect
discovered by his assistants P. Ribkin and D.
Troytskiy. This receiver was later patented
in Russia, England and France.
On January 22, 1900 - this receiver was
patented in France (№296354), on April 7,
1900 – it was patented in England (№2797),
on November 30, 1901 - patented in Russia
(№ 6066).
There exists the document which describes
the A. Popov invention of the first practical
semiconductor crystal diode. The copy of
the patent which A. Popov accepted in
3
England on the 7
th
of April 1900 is enclosed.
(See reference №2 in the Appendix)
In 1900 The Diucretet Firm in France started
the industrial production of such diodes and
A. Popov’s detection radio receivers.
In 1875 Braun worked on the subject of
semiconductors but his works were only
theoretical. They showed one way
conductivity of contacts between different
objects (crystal and amorphous).
After the A. Popov’s patents Braun has
returned to the matter in question. The
Germans refused a patent to Popov as Braun
has already made a research on this subject
but there was no practical application of his
works.
As a result the German firm Siemens and
Halske/Telefunken has signed a 3 sided
agreement on the application of A. Popov’s
invention for the radio apparatus production.
In 1900 Popov’s device was used when a
47 km kilometer long radio line, linking the
island Kutsalo (town Kotka - Finland) and
the island Gogland in the Finnish gulf was
installed. The radio line was constructed to
help a battleship “The General – Admiral
Apraksin” which ran aground because of a
navigation error. The first wireless message
received by the radio line allowed saving the
lives of 27 fishermen who had been carried
away on a block of ice in the sea-way. That
successful operation of the radio line
resulted in taking a decision to use the radio
at ships of the Russian Navy. This line was
the first to use radio communication and it
worked more than 3 months.
Continuously improving his
radiotelegraph Popov succeeded in
implementing radio communication in the
army, navy and newly born aviation as well
as civil branches. But the development of
radio in the tsarist armed forces proceeded
very slowly, compared with those of other
European countries.
Popov was personally involved in
launching the production of Popov system
equipment not only at the E. Diucretet
factory in Paris (1898), but also at the radio
workshop in Kronstadt founded on his
initiative in 1900 and at the Siemens and
Halske factory in St Petersburg (1904).
In 1901 A. Popov was appointed
Professor of Physics at the St Petersburg
Electrotechnical Institute where he set up a
wireless telegraphy research laboratory and
gave a course on the subject.
Electrotechnical Institute founded in
1886 became the first to specialize in
electrical communications. Together with
his post-graduate assistant S. Y. Lifchits in
1904 A. Popov conducted experiments in
transmitting the human voice via radio.
In 1905 he became the first elected
director of this institute.
In December 1905 A. Popov was ordered
by the Governor of St Petersburg to take
repressive measures against student political
disturbances (it was the time of the first
Russian Revolution which was supported by
many progressively – minded people
including students and lectures). A. Popov
refused to do it. He took these events too
close to his heart which badly affected his
health.
He died on the 13
th
of January 1906 at the
relatively young age of 46.
IV. A. Popov’s Heritage in St Petersburg
Historians of science in many countries
of the world including Russia do full justice
to numerous experiments and investigations
sifting out from them those facts and
interpretations that remain meaningful
today. It should be mentioned that the most
valuable arguments for the history of science
are supposed to be those facts which are
confirmed by archives documents.
There are 3 museums in St Petersburg
that commemorate the prominent Russian
scholar in the field of physics, electrical and
radio engineering.
4
The first exposition of Popov’s
experimental devices was opened in
Kronstadt in 1906.
The biggest collection is in The Central
museum of communication named after A.
S. Popov which keeps original devices
designed by A. Popov himself such as his
radio receiver, a lightning recorder, Hertz’s
vibrator (oscillator) used by A. Popov as a
transmitting device in his radio signaling
system.
The memorial museum of A. S. Popov in
“LETI” (The St Petersburg State
Electrotechnical University) is a scientific
research and a scientific educational branch
of St Petersburg State Electrotechical
University which collects, keeps and studies
apparatus, different publications, findings,
historical facts, concerned with the life and
activities of A. Popov – the inventor of radio
and the founder of teaching programmes on
wireless telegraphy for military and civil
higher schools.
The Museum also takes great interest in
the documentary material on the origin and
development of electrical engineering and
its main directions, the foundation of which
was laid by A. Popov, his co-workers and
followers. In collaboration with the
Electrotechnical University the museum
carries out scientific research on the history
of the development of electrical engineering,
radio engineering, electronics and
communication.
On the basis of its scientific
investigations the museum organizes
different stationary and temporary
exhibitions devoted to the history of science
and engineering and to famous scientists and
inventors.
The memorial museum of professor
Popov was opened on the 25th of June in
1948 in his former laboratory in ETI where
the scientist worked during the last period of
his life from 1903 till 1906. A. Popov
performed 42 laboratory experiments using
his devices for the 1st and 2nd year students.
A. Popov was an extremely gifted and
many-sided scientist who carried on his own
investigations in the field of electrical
engineering, optics, radioactivity, wireless
telegraphy. Physical devices and apparatus
kept in the collection of the museum show
Popov’s professional activities and scientific
interests. Numerous museum stands
demonstrate the main periods of the
scientist’s life, his scientific and social
activities. The museum collection started
with over 80 devices which belonged to A.
Popov and professors O. Hvolson and V.
Skobeltzyn. The museum got these devices
from the chair of physics of the
Electrotechnical Institute.
Of special value in the museum
collection is Popov’s apparatus for
transmitting and receiving signals made in
1896. A. Popov demonstrated this apparatus
– the receiver and the vibrator with
parabolic reflector at the section of the
Russian Physical and Chemical Society at
the St Petersburg University on the 24th of
March in 1896. The apparatus transmitted
and received signals at the distance of 250
meters between the buildings of St
Petersburg University. At present the
devices in the exposition of the museum –
laboratory are arranged in such a way that it
is possible to demonstrate the main
phenomena of the electrical engineering just
in the course of the excursion using the
devices on display.
For example, electromagnetic induction
phenomenon can be shown by the
experiment performed with the help of M.
Faraday’s scheme. Riss’s spirals made as far
back as 1900 can also operate quite well
even now enabling to reproduce some
experiments on fundamental physical
phenomena.
The museum collection consists of
devices, instruments as well as scientific
papers, letters and journals which are of
5
special interest to foreign scientists and
historians in the field of science and
engineering.
The museum keeps Popov’s archives
including the papers describing his first
experiments in the field of wireless
signalization as well as his own library and
his correspondence with colleagues both in
Russia and abroad.
The museum collection exceeds 15 000
items. Of special value are Popov’s personal
archives containing over 1000 papers, his
own instruments and devices designed in the
period from 1889 to 1906 and a wireless
telegraphing system of commercial
production.
As a matter of fact Popov’s memorial
museum is a unique scientific technical
museum with wonderful opportunities for
young specialists who take interest in the
origin and history of electrical and radio
engineering.
Speaking about the memorial museum
one can’t help mentioning Popov’s younger
daughter E.A. Popova-Kjandskaya (1899-
1976) who was the first director and founder
of the museum. She was an honorable
person of the Russian Federation involved in
the arts and an honorable member of the
scientific and technical society NTORES
named after A. Popov. For many years the
museum was supervised by her daughter
E.G. Kjandskaya (1934-1994) who
contributed to the foundation and
development of the museum. A. Popov’s
daughter published over 40 papers and
presented about 50 reports. She took part in
the work at 30 films devoted to Russian
scientists and participated in the preparation
of 46 museum expositions in Russia and
abroad.
Due to their efforts the museum was
included in the catalogues of the museum of
the world. It is popular with tourists of St
Petersburg. It is visited by tourists and
delegations from USA, Germany, Great
Britain, France, Poland, China and other
countries.
In September 2003, the IEEE Russia
North-West Section received High ranking
Officers: IEEE President 2003 Michael
Adler, his wife Virginia and 2001 IEEE
President Joel Snyder in St. Petersburg.
They visited the Alexander S. Popov
museum.
V. Conclusion
Every country is proud of its great
people: writers, poets, actors, composers,
painters, scientists and inventors. Russia is
not an exception. It is proud of prominent
scientists and inventors who made great
contribution to the development of different
scientific fields and more rapid progress in
science and engineering. One of such
scientists and inventors was A. Popov.
To summarize Popov’s achievements it is
to be noted that A. Popov’s scientific work
can be treated as a balance between
theoretical assumption and practical
application of the latest findings. He
succeeded in putting his own and other
scholar’s concepts into practice.
A. Popov often went abroad, he visited
many European cities: Paris, Berlin,
London, Zurich, made a trip to USA where
he visited New York and Chicago. He met
foreign scientists, exchanged scientific
information and kept up working contacts
with them. They discussed many scientific
problems of common interest which turned
out to be fruitful and efficient for scientific
and engineering progress.
A. Popov wrote a letter to the editor of
the Journal “The Electrician” on 26
November 1897 concerning the problem in
question: “I constructed an apparatus
very useful for the demonstration of the
properties of the Hertzian
electromagnetic waves and rays in a
large lecture-room, also fit for registering
6
atmospheric electric disturbances... On
using a sensitive relay in the circuit
with the coherer tube, and an ordinary
electric bell in a collateral line for sound
signal and as an automatic tapper for the
coherer, I received an apparatus which
exactly answers every electric wave by a
short ring and by rhythmical strokes, if
electric vibrations be excited
continuously...”
Opening the International Conference on
wireless telegraphy in Berlin in 1903 the
Minister of Posts and Telegraphy of
Germany Kretke said: “… in 1895 A. Popov
invented reception of telegraph signals by
means of the Hertz waves. It is him that we
should thank for the first radiographic set.”
At the end of the 19
th
and at the
beginning of the 20
th
century Popov had
close contacts with prominent scholars of
Russia – D. Mendeleev, S. Makarov, A.
Krylov, A. Lodygin and others.
All these allied to his foresight and wide
knowledge enabled him to get recognition in
scientific community. A. Popov’s
contemporaries highly appreciated his
achievements.
One should make reference to O. Lodge’s
letter dated September 1, 1908 “…I have
always thought highly of Professor Popoffs
work in connection with wireless telegraphy.
It is true that I used an automatic hammer, or
other vibrator driven by clockwork or other
mechanism, to restore the coherer to
sensitiveness; but Popoff was the first to
make the signal itself actuate the tapper-
back; and that I think is the novelty we owe
to Popoff…”
“I conjecture that Popoff may have been
one of the pioneers who applied the method
to ship signaling of some rough kind at an
early date.”
“I shall be happy to answer any other
questions, and am glad that professor Popoff
should have his work recognized in his own
country.”
A. Popov was in the best and truest
senses of the word both a remarkable
personality and a genuine scientist:
kindness, courtesy and consideration were
part of his nature. These features of
character enabled him to guide, assist and
counsel on scientific, organizational and
personal problems with a skill and tact
which were highly effective.
A. Popov paid great attention to all new
investigations not only in the field of
physics, radio-activity and electrical
engineering, but in making electrical
machines and designing roentgen devices.
He designed and continually refined the
apparatus used for radio communication, he
organized the training of experts in this field
and initiated the setting up of the first
wireless telegraphy transmitters in Russia.
During his lifetime A. Popov was being
held in high esteem in Russia and abroad.
He was given many honorary titles and
awards as a great inventor. A. Popov had an
honorary title of an electrical engineer. A.
Popov was awarded a gold medal and
diploma at the World Exhibition in Paris in
1900 for developing wireless apparatus and
a lightning recorder.
Monuments have been erected to him in
several Russian towns. A gold medal and
prize have been instituted in his honor and
awarded by the Russian Academy of
Science to Russians and foreigners for their
outstanding work in the field of radio
engineering. 20 Russian scientists were
awarded this medal. One of them is J.
Alferov, Nobel Prize Winner in the field of
physics, a graduate of the Electrotechnical
Institute who was awarded the gold medal
named after A. Popov in 2000.
In 1945 on the 7
th
of May a state holiday,
the Day of Radio was established. Every
year on the 7
th
of May a tribute is paid to our
great compatriot A. Popov – a great scientist
and inventor.
7
VI. Reference List
1.
Berg A.I. Radio Invention by A. Popov. – Moscow, 1966
2.
Berg A.I. Radovsky M.I. Radio Invention by A. Popov.- Moscow, 1949
3.
Brenev I.V. Radio Invention by A. Popov. -Moscow, 1965
4.
Rybak D., Kryijanovski L. G. Marconi and the development of radio communication//
Radio, - 1995. - №1 – p.15-17
5.
Zolotinkina L.I. Radio Bibliography. – St Petersburg, 2002
6.
Dictionary of Scientific Biography Vol.11 New York, 1975
7.
EBU Technical Review.- Spring 1995.- №263
8.
The Electrician.- 1925.- №4
9.
Urvalov V.A. G. Marconi/Electrical Communication, - 1995. - №2 – p.37-40
10.
The St Petersburg Electronics Journal. – 2002.
VII. Original Publications on A. Popov Invention
1.
Kronstadtskiy Vestnik, 1895, 30 April (12 of May), №51, p.1
2.
Protocol № 151 (201) of the Physical Section of the Russian Physical and Chemical
Society in St Petersburg on 25 of April 1895//Russian Physical Chemical Society Journal,
1895, Vol. 27, p.259
3.
Lachinov D.A. The Fundamentals of Meteorology and Climatology.- St Petersburg,1895,
July
4.
Popov A.S. The Apparatus for Detecting and Recording Electrical Oscillations.// Russian
Physical Chemical Society, 1896, Vol. 28, №1, p.1-14
5.
Popov A.S. The Apparatus for Detecting and Recording Electrical Oscillations. A
reprint// Russian Physical Chemical Society Journal, 1896, St Petersburg, 14 p.,
6.
Popov A.S. The Apparatus for Detecting and Recording Electrical Oscillations.// The
Electrician, 1896, № 13/14, p.177-189
7.
Popov A.S. The Apparatus for Detecting and Recording Electrical Oscillations. A
reprint// Metereologicheskiy Vestnik, St Petersburg, 1896, 7 p.
8.
An Apparatus for Detecting and Recording Electrical Oscillations in the Atmosphere.
//Metereologicheskiy Vestnik, 1896. №3
9.
Protocol № 158 of the Section of the Physical Section of the Russian Physical and
Chemical Society on 12 of March 1896, Vol. 28, p.124
10.
Scobelzin V.V. A.Popov’s apparatus for Detecting and Recording Electrical
Oscillations.// Post – Telegraph Journal, 1896, April, Vol 46, p.546
11.
Wireless Telegraphy. (A letter to the Editorial Office). //Kotlin, 1897, 8 January, № 5, p.2
8
Appendix
Reference №1
Reference №2
A.D.1900 Feb 12 №2797
Popov’s Complete Specification
9
Date of Application, 12th Feb., 1900-Accepted, 7th Apr., 1900
COMPLETE SPECIFICATION
Improvements in Coherers for Telephonic and Telegraphic Signalling.
I,
ALEXANDER STEPHANOVICH POPOV
,
of Cronstadt, Russia, Professor, do hereby
declare the nature of this invention and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement
5 The improved receiver of messages sent into space by means of electromagnetic
oscillations, is based upon Branly's discovery of the tubes filled with filings, known
as coherers or radioconductors and presenting a great resistance to the passage of
electric currents and adapted to become suddenly conductors when influenced by
electric oscillations, even when these oscillations have but
10 little strength, which reach said tubes either directly or through conductors secured to the
tubes, said conductors serving to collect the electric waves.
The change of resistance is ordinarily accomplished instantaneously and continued
after the passage of the electric oscillation: in order to stop the conductibility of the
metal filings, as quickly as is possible, the tube is ordinarily
15 shaken or jogged, and to this end automatic devices have been invented.
My improved receiver comprises the omission of this means for restoring' the
resistance of the filings, and it will be sufficient to compose my tube with the
result to be obtained in view. The result has a real importance and is attained by
composing the tube of a conducting chain formed of carbon and
20 metal portions placed alternately and having what is known as "free micro-phonic
contacts." Thus the changes or variations of the resistance are less considerable,
and of shorter duration and constancy. At the first influence, the resistance of
such radioconductors decreasing, it maintains still a certain value, and during all
the time of the influence of electric oscillation, said
25 resistance will be varying without it being- necessary to shake or jog the tube. These
variations of the resistance are easily perceived in the telephone.
Under these conditions, the arrangement of the improved receiver, according to
the accompanying drawings illustrating the invention by way of example,
embodies in its main portion:—a circuit composing the tube filled
30 with filings, one or more elements of a buttery, one or more telephonic
apparatus in which the operator hears special sounds, which are dry, short or long
and correspond to each discharge at the transmitting station; thus at the receiving
station, I obtain a good reception of the signs of the Morse code. The character of the
action of the switch for the induction coil is not at all affected
35 and it is thus possible to distinguish from each other, cablegrams transmitted bv
different stations and received at different moments.
The employment of the telephone in connection with Hertz's sounding board at
micrometric intervals has been realized by Mr. Turpin, but this arrangement is
convenient only for classic experiments at short distances, and cannot be
40 combined with my system of tube (special radioconductor) filled with steel grains,
having free contacts, and producing the shortest distances between them which
cannot be obtained by any Hertzian sending board. My improved device enables me to
transmit messages without conducting-wires to very great distances.
11
№ 2797,—A.D. 1900.
Popov's Improvements in Coherers for Telephonic and Telegraphic Signalling.
The radioconductors heretofore employed do not attain this result unless they
are arranged as above indicated. To this end, the most convenient metal is merchant steel in the form
of polished pearls, which when crushed, produce grains, by means of which I obtain radioconductors
of steady and perfect sensitiveness.
5
The support of such radioconductors must protect the latter from too sudden jerks during the
reception of a message, which result in easily obtained by securing the support by means of soft
india rubber or in any other suitable way.
The sound in the telephonic apparatus may be perceived at a certain distance from the ear. The
employment оf two telephonic apparatus enables the
10 operator to be insulated from the exterior sounds. The addition of a telephonic apparatus
arranged in microtelephonic relays for the alarm and for recording messages, is well known.
The radioconductor (or coherer) I preferably employ, is arranged as follows: —
(see Fig. 1 of the drawings):—within a small tube of glues or other insulating 15 material arc secured two
small blades of platina arranged in proximity to each other; said blades are secured to the mountings or
pieces, and two outer conductors terminate these electrodes. The interior of the tube, receives
hard steal grains produced by means of crushed pearls as already stated. However metals or hard carbon
may be employed for the same purpose.
2 0
The size of the grains depends on the distance between the inner blades.
The groins produced by means of hard steel pearls have on their polished portions a thin layer of oxide,
whilst the inner portions of the pearl have a thicker layer of oxide. Furthermore the parts which are
broken away, present points or projections on which no oxide is formed. This variation of the state of
oxidation on the surface of the metal grains, together-with the similarity of their form, ensures a
perfect sensitiveness and steadiness, and the improved radioconductor is thus convenient for the telephonic
reception of electromagnetic waves, produced at large distances.
In order to facilitate the uniform distribution of the grains, the tube may 30 be divided by
means of partitions made of non-conducting material, into several sections or chambers.
Fig. 2 illustrates the most simple form of the device at the receiving station, but is possible to
combine other devices intended to guard against the effect of atmospheric electricity and telluric
currents; said devices are applied to 35 the wire or collector C о and to the ground wire and their
circuits.
Fig. 3 shows a device having: a converter Т r (I I' are the primary and secondary windings) as
employed at microtelephonic stations; said device i n creases the intensity of telephonic sounds, but
muy be omitted.
Having now particularly described and ascertained the nature of my said 40 invention, and in
what manner the same in to be performed, I declare that what I claim is: —
1.—The combination of radioconductors with one or more telephonic appara-
tuses, for the purpose of dispensing with the usual means for shaking or jogging the radioconductor
(or coherer), and with the relay usually inserted 45 into .the circuit of the radioconductor.
2.—The application of steel pearls crushed to grains of suitable size substantially as and for the
purpose set forth.
Dated tins 12th day of February 1900.
ROBERT E. PHILLIPS, Assoc. M.Inst.C.E,,M.I. Mech. F.. 50
Chartered Patent Agent, 70, Chaneery Lane, London, W.C., Associate Agent.
Printed for Her Majesty's Stationery Office, by Malconisou & Co., Ltd.—1900.
12
Document Outline - The radioconductors heretofore employed do not attain this r
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