Northern Wisconsin advertiser. [volume] (Wabeno, Wis.) 1898-1925, 1903-01-22
WIRELESS TELEGRAPHY.
All Systems Operate on the Same Gen
eraI Plan.

eral Plan.
In a recent article NJ. Solomon dis
cusses the state of the art of wireless
telegraphy Up to quite recent date.
So far as can be judged, the various
systems differ chiefly in the matter of
detail. the design of circuits and the
special construction of apparatus. I'm
provements depending upon the intro
duction of a princile fundamentally
new are few and far between At
tempts which have been made at syn
tonization are far from encouraging,
although many inventors claim to
have solved the problem. From a con-
sideration of the Carlo Alberto expert
ments it is thought to be possible to
tap the signals that are being sent
over long distances without special
preparation. The author then takes
up the discussion Of the success which
has been attained in sending and re-
ceiving signals over great distances.
At the time this article was written
the recent announcement that Mr..
Marconi had sent messages from Cape
Breton, Canada, to Poldhu, Cornwall,
England. had not been made. 1t is
regretted that no comparison is pos
sible as to the power required by the
different systems in sending messages
over given distance. A description
of M. Guarini's automatic repeater is
then given. This is an apparatus
which is designed to pick UP mes
sage received at one station and pass
it on to a second. An aerial wire at
the repeating station is connected
! through the contct of a relay and
through the primary of transformer
to earth. 1t is also connected through
spark-gap to earth. The coherer
! is connected in series with the Sec
ondary of the transformer and a con-
denser. When the signal is received
the resistance of the coherer is broken
down and battery sends a current
| through it and a second relay which
closes a circuit actuating the first re-
| lay. The effect of this is to discon-
meet this latter relay from the aerial
wire and connect it to the circuit con-
| tanning a series of batteries and the
secondary of a transformer. The pri-
mary of this transformer is connected
in circuit containing a spark-gap ard
a condenser. This causes a spark to
pass cross the gap and sends the mes
sage on. The author then discusses
the problems presented in breaking
| circuits carrying such heavy currents
as are used at Poldhu, and then passes
, to a discussion of the various types
of coherers. For long-distance work
it is generally found more suitable to
use coherer which requires no tab
ping back, but spontaneously returns
f, to its normal condition. This enables
q telephone to be used as the receiv-
, ing apparatus, the telephone requir-
| ing much less energy than an ordi-
, nary sounder. Such coherers are
those of M. Popoff, consisting of car
the De Forrest anticoherer, which is
composed of viscous material loose
conducting particles and an electro
/ lyte. and the Castelli coherer. this lat
ter being formed of two or more cleo
trolyte. and the Castelli coherer, this
latter being formed of two or more
electrodes, either of iron or carbon,
between which is introduced a minute
drop of mercury. The Marconi mag
| netic detector is then described and
illustrated diagrammatically. The
author expresses regret that so much
work has been spent in signaling long
distances. while the desirable appli-
cation to ships has been more or less
eglected.-Nature. London.