Evening star., 1924-05-09
TALK TO NEIGHBORS
! WITH RECEIVING SET
Simple to Do, But Expert Refuses
to Reveal Secret
Hook-Up.
AFRAID OF INTERFERENCE
Air Already Crowded With All
Sorts of Noises.
AFRAID OF INTERFERENCE
BY l.. o. MARSTELIER.

BY l.. o. MARSTELLER.
nadio Engineer. Westinghouse F,Iec-
1c and Manufacturing Company.
Every one is interested in learning
the trouble that has been and NAV
oe caused by operating a miniature
oroadcasting station. and moro
greatly interested in how to prevent
this Interference,
Nearly all the sensitive receiving
sets In use are capable of broadcast
ing speech and music. This can
readily be done by the use of a
inlcrophone properly connected to
receiving set. Before proceeding
iurlher, let me explain that a micro
phone is a simple little device, one
form of which we use every day.
namely, the part of the telephone
INTO which we talk. Talking into a
very sensitive microphone causes the
voice to affect the powerful radio
waves sent out by the transmitter
WhIch is fundamentally a large sensi-
I've receiving set having a micro
pnone connected to it. The tickler
On lhe transmitter is necessarily ad-
Justed so as TO make the circuit
oSc!llate and consequently transmit
radio waves. just as your receiving
SeI VIII do with similar tickler ad-
1ustment.
Hook-Up Secret.
II l thought you would use the
mlcrophone only to reprmand your
neighbor, who is causing his receiv-
ing set to transmit whistles and
squeals, then I certainly would ex-
plain how to connect the device to
Your set. However, there is always
nf hn 1o1 h~nn
casting tea party gossip or the un-
canny east or west wind from
mah-jong party, so l shall leave the
home broadcasung'' idea for you to
think about.
The purpose of mentioning the pos
sibility of using your receiving set
aS a broadcasting station is to call
your attention to the power you con-
troll with the knobs and dials on your
set.
If you do not have a microphone
connected to your receiving set, you
can still transmit. but 1t Will be
source of interference to your neigh
borS-
Can Be Eliminated.
Many times during the reception
of an interesting program one will
hear whistle or squeal caused by
neighbor who improperly manipulates
he can very easily prevent such in
reference is an excellent reason for
paying him visit and explaining the
situation. Before paying your neigh
Dor this instructive visit, however, II
would be well to learn the cause, Ell
feet and remedy for such interfer-
ence.
There are several types of receiv-
ing sets which can be made to act as
a transmitter. Tho first of these Is
the favorite set, a single circuit re-
ceiver. One of these controls IS
known as a tuner handle or knon.
This control makes it possible to
tune in one station and eliminate an
other The other control is a ticker
or intensifier. Its purpose is 10 IN
crease the signal strepgth, IS hs n,erefed efed
simultaneously Now let us consider
the proper operation of this set.
Proper Operation.
With the ticker set near Zero bring
the tuner control to approximately
the setting where you would expect
to find the desired signal, and, with
the other hand, bring the ticker
control up to the point where SllSnt
hiss or rustic is heard and keep the
tickIer so adjusted as you more ac-
surately tune in the signal Never
increase the tickler beyond the point
where the kissing sound is heard or
YOU will hear whistle or sQueai,
indicating that you are sending an
interfering wave which Will inter-
fere with your neighbor's reception
If a slight change of the tuner ad-
justment causes a Squeal or whistle
to be heard, you should Immediately
remedy matters by decreasing the
ticker until the whistle disappears
If you do not decrease the ticker
setting your set will continue to act
as transmitter and radiate an In
terfering wave. This will cause your
neighbors to receive whlstlellke
noise mixed in with the concert music
from the broadcasting station. Many
times music of excellent quality is
condemned because of the interfer
ence caused by the wave sent out
from a neighbor's receiving set
With very little practice the
single circuit receiving set can be op
Grated, night after night, without
causing any Interference.
Another Type of Set.
Another type of receiver which
often finds a place in the amateurs
home and sometimes is used for
broadcast reception has one more
control than the single circuit set
making a total of three controls.
One control tunes the primary or
antenna circuit, and the other tunes
the secondary or tube circuit. The
third control is marked tickler or in
tensifier. This receiver is very Sc
lective, but requires considerable skill
and patience in order to tune in weak
signals. AS this type of receiver has
three controls, and, as the average
person has but two hands, it is rather
difficult to keep the tickler properly
adjusted as the primary and secon-
dary controls are operated. The gen.
era1 tendency is to set the tickler to
maximum and then tune the primary
and secondary until the whiStlelike
note of a broadcasting station is
heard. That means that the opera
I- l.
your neighbors reception of the con-
cert
Celebration Essential.
For people who have only two
hands, there is only one way to oper-
ate such set and not cause inter-
ference-that Is, to calibrate the sec
ondary circuit by marking the proper
setting down on a chart Then, to
tune in station, it is only necessary
to set the secondary control to the
proper point as determined from the
celebration chart and adjust the tick
ler to the point where a slight hiss
or rustic is heard as the primary cir
cult is tuned to the desired signal
There is one other receiver which
is commonly used. This receiver
ence, as it has three tuned circuits.
Two of the controls are marked 'pri-
mary and secondary" and are ma
nipulated to tune in a signal. The
third control acts as ticker, and
has a definite adjustment for each ad-
justment of the secondary circuit.
with this type of receiver it is al
most impossible to tune in a station
without radiating an interfering
wave Every time that the third con-
troll is tuned to the secondary circuit
an interfering wave will be radiated.
Range Four Blocks
How far will any one or all Of
these three types of receivers trans
nit? Any one will cause interference