Improvements in Hertzian Wave Telegraphy to Enable Signals to be Transmitted to any Distance by Means of Intermediate Relay Stations.
Year: 1899

page_text: Date of Application, 11th Apr., 1899
Complete Specification Left, 11th Jan., 1900 - Accepted, 17th Mar., 1900
Improvements in Hertzian Wave Telegraphy to Enable Signals to
be Transmitted to any Distance by Means of Intermediate Relay
Stations.
We, PHILIP HENRY COLE, of 20, Lessing Street, Honor Oak Park, London, S.E.,
Electrician, and BERTRAM COHEN, of 41, Cornwall Road, Westbourne Park,
London, W., Electrician, do hereby declare the nature of this invention to be
as follows:-
In this invention the improvements consist of a means of transmitting signals to
any distance through space by the use of intermediate stations which can receive
and automatically re-transmit the signals by means of relays on to the next
station and so on until the desired station is reached.
This may be accomplished by providing at the intermediate stations a relay in
the local circuit of the coherer so that when closed it completes the circuit of an
induction coil and the signal is re-transmitted to the next station.
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It is found that when a signal is re-transmitted, oscillations are set
the whole system; thus if No. 4 is retransmitting, it affects both No. 3 and No. 5
which in turn react on those on either side of them, and this action will go on
until the source of power is exhausted.
There are several methods of preventing these surgings of which we mention
the following.
In one method the armatures of the relays at each station can be arranged to
cut off the receiving apparatus whilst re-transmitting and so adjusted that when
the back surging reaches the station the receiving apparatus is still disconnected.
This method would rather slow down the message speed.
Another method using a synchronized commutating arrangement at every
station might be adopted, connected in such a manner that as soon as a signal
has been sent, the receiving apparatus is cut out at the sending station and so
cannot be effected by the back surgings from the next station. Thus sav No. 2.
is transmitting, the receiving apparatus at No. 1 is out of circuit and No. 3 only
will receive the signal and the same applies when No. 3 transmits and so on.
A third method can also be employed in which two vertical wires are used at
ach station the pair being screened from each other in their entire length by
wo semi-cylindrical metal poles placed with their convex sides together and fitted
with hoods at the top so that signals can only be received from one direction by
one wire and transmitted in the opposite direction by the other and vice versa.
Dated this 11th day of April 1899.
PHILIP HENRY COLE.
BERTRAM COHEN.

page_text: Improvements in. Hertzian Wave Telegraphy to Enable Signals to
be Transmitted to any Distance by Means of Intermediate Relay
Stations.
We, PHILIP HENRY COLE, of 20, Lessing Street, Honor Oak Park, London, S.E.,
Electrician, and BERTRAM COHEN, of 21, Tavistock Road, Bayswater, London,
W., formerly of 41, Cornwall Road, Westbourne Park, London, W., Electrician,
do hereby declare the nature of this invention and in what manner the same is to
De performed, to be particularly described and ascertained in and by the following
statement:
In the accompanying drawings Sheet I shews the apparatus and connections
of an intermediate station in which a a' are poles, each for receiving and trans-
mitting in one direction only, this being effected by means of metal screen b
this is shewn in detail on Sheet II) c is an induction coil with spark gap d for
transmitting waves, c and el are coherers for receiving purposes and in conjunc-
tion with these are main relays h and actuated by cell w also auxiliary relays
and, main battery s, decoherers f and f', condenser t and earth v.
The method of operating, and details of connections are as follows.
The terminal or first and last stations of a system are equiped in any suitable
manner for transmitting and receiving Hertzian waves, the intermediate stations
being equiped as shewn on Sheet I.
1.
Let us presume a wave is sent from the first station, which is received on pole a
of the first intermediate station, this wave passes from pole through relay
tongue m of auxiliary relay to upper contact o, through coherer e to earth,
thereupon closing circuit of main relay h, the armature and contact of which
are joined through main battery s to auxiliary relay, which is actuated, thereby
depressing tongues m¹ and n¹ on to contacts p¹ and respectively. The upper
tongue m thereby disconnnecting, coherer from pole a and connecting the
latter through contact p¹ to spark gap d of induction coil c. The lower tongue n¹
connects up through contact the main battery s, decoherers f and fi and
primary of induction coil c, thus re-transmitting from pole a to the second inter-
mmediate station the signal received on pole ae The same action takes place at
every other relay station, the signal being received in the ordinary way at the
last station.
When signals are being sent in the opposite direction a similar action takes
place. It will thus be seen that a wave is transmitted in one direction only.
Two methods of screening the poles are shewn on Sheet II.
Fig. I shews the two poles a screened from each other in their entire length
by two semi cylindrical metal shields 6 placed with their convex sides together and
capped by metal hoods y, (another elevation of this pole is shewn on Sheet I
letters a ab and y). Fig. II shews a method by which the effects caused by the
close proximity of the metal shield b to the poles a a¹ are obviated, these being
placed some distance apart and metal screen 6 placed midway between; th's
figure shews a plan and elevation of this arrangement, 2 and 3 are huts con-
taining the apparatus, these are preferably made of corrugated iron so as to screen
the apparatus contained both from atmospheric and Hertzian wave effects, 4 and 5
are stays to support screen b.
In Sheet I the auxiliary relays are introduced to avoid placing a number
of contacts and tongues on the delicate main relays h h¹.
In practice the tongues of auxiliary relays and would be constructed so
as to have a large range of motion and to make contact in mercury cups.

page_text: There would also be a screen between contacts so as to prevent leakage of
waves across air gaps.
Signals in either direction can also be sent from any intermediate station by
attaching press buttons to armatures of auxiliary relays and using them
as Morse keys.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that what
we claim is:-
1. Improvements in Hertzian wave telegraphy to enable signals to be trans-
mitted to any distance by means of intermediate stations inserted between the
two main or end stations, each of said intermediate stations being provided with
transmitting and receiving apparatus and a combination of relays so that a signal
received at the first of such intermediate stations is retransmitted to the second one
and so on, each intermediate station being also provided with a means of pre-
venting the re-transmitted signals affecting the stations on the route back towards
the station which originated the signal all substantially as and for the purpose
set forth.
2. The use in connection with any system of wireless telegraphy of the herein
described intermediate relay stations adapted to operate and connected up sub-
stantially in the manner and for the purposes set forth.
Dated this 11th day of January 1900.
PHILIP HENRY COLE.
BERTRAM COHEN.