The Wolf Point herald. (Wolf Point, Mont.) 1913-1940, 1922-06-08
THE HOME RADIO
Hoxu 70 MaLa and IIsa II 60 By A. HYATT VERRILL
49," ~ A~ N Oo~ ~ CWyahty Harper Brothers
II. PRINCIPLES OF WIRELESS TRANSMISSION

Before attempting to explain the functions and the principles Of the radio
to understand something Of the underlying principles and fundamental laws
It is not however necessary to enter into a long discussion Of the theories
merely tc illustrate and make clear a few important and salient laws causes
and results which make the transmission of sounds possible without the use
of wires between the sending and receiving instruments
The first m los important principle , Of all radio adj transmission is IN
tons o. IS we may call them for the sake # simplicity, waves. We arr accus-
toned to think of the atmosphere about US IS aemoe or less uniform sub
stance which W call air, but in reality the air O atmosphere space, and in
fact all solids as well are pervaded by an invisible odorless and almost weight
# is h means of This ether tatan heat light electricity ETC. are ransmitted
in the form of waves or vibrations. Light and heat waves have been known
to science for a long time but it is only within comparatively recent years
that a has learned that electric or electromagnetic waves also travel
through the ether. and it was through this discovery and by means of these
waves that wireless telegraphy and telephony became possible In a way,
bv dropping a stone in a aim pool Of water for lust as the water aves
travel in gradually widening circles from the splash, % the electric waves,
started by the spark If a wireless transmitting or sending instrument spread
in overwhelming circles through the ether. Moreover just as the waves in
the pool are short and clear near the spot where the stone is thrown and grad
the splash, Sc wireless waves are clearer and sharper neart the instrument and
decrease in ceaness and size a they get farther and farther away and, to
draw still another comparison. just as the shore of the pool or any object in
u interrnnt o. receive n aecfricaI waves 81 te ether indeed INST as The
waves o vibrations set up by the wireless spark are electromagnetic waves
are started by muscular n mechanical energy. You can readily understand
if "A person at a distance should toss stones into the water at stated intervals
a person watching the shore, and noticing the intervals of the waves. could
. por crnde and an@ nnc cti D matbod of Of mmnoGatt h." f vl con I5% devise
creating waves of definite sizes and numbers a practical means of communiGa,
ton could be established 1t is just this which occurs in the transmission and
reception of electromagnetic or wireless waves for by breaking or nteruptng
the waves sent out by the spark they are transformed into long and short sec
These vrayas St in motion nv tbe sendinga nnarst1e nossas te nranerp ~
aerial O antennae o a wireless station they start oscillations in the wires,
but 20 faint and weak that they would not be detected unless sensitive tnsru-
were provided to magnify and catch them. Such instruments are known
as detectors IN consist OF various substances or devices which are adjustable
and from which wires lead to a telephone receiver The high frequency o31-
latons Of the ether, which are known as alternating currents, as they flow
back and forth, ire cut off by the magnets in the receiver, while the detedor
is designed to allow the oscillations to pass through in ne direction, but will
not allow them to return and thus it acts as a checkvalve in a water pipe and
the alternating, back-andforth currents are transformed into impulses going
in one direction only and known al direct currents These will flow through a
telephone receiver md aus the diaphragm % vbrate, an thus the ear detects
the interrupted buzzng sounds which Indicate the dots and dashes of the code.
Another very important part of the mechanism of the wireless apparatus is the
tuner for without this the various vibrations Of the ether sent out from num-
berless stations would come as a hodgepodge of meaningless sounds to the
receiver. But by arranging the receiving instrument Sc it may be adjusted to
receive O. pick up only those waves of a certain length, all other vibrations,
s snu ay uh he is Receiving Giving mes meaa @s may n%" adjust IT. his it instrument p9r s@ B back k" and forth pb
until he picks up any message which may be passing through the ether at the
time.