8
II
V IMS (M i
BT SAUL EMANUEL
O you know tha difference be-
een a "volf and ao' -am
pere" 7
Thea two terma. which are ued
the measurement of electricity
Knd electrical circuits, often have
been confuted by the norlce In the
radio same. Many think they are
wo names for the same thins;.
The terms "toll," "ampere."
"watt" and "ohm" are being en
countered dally by the thousands
Eho hare taken bp the radio as a
eana of amusement or entertaln
ent. y
A knowledge of thee common
Mectrlcal terms ahould prove of
krreat Interest to these persons and
there who are reading of the radio
rniraclea nearly every day.
ho volt la the unit of electrical
rresaure. r rather, difference in
ressura. Wherever there happens i
to be a difference i.: preau-,
' whether I; be in water or electricity.
there wll! be a movement or flow.
If thf presure of one end of the
electrical circuit Is greater than that
of the other end. whit is known a
current of electricity will flow. This
wilt flow as Ionic as the difference
of pressure exists. The voltage Is
the amount of difference; In the
pressures.
When the current flows it must
have a certain strength or amount
of flow. This strength is measured
In amperes. If the pressure be
tween the ends of the circuit Is
raised a larger amount of current
will flow. Thus, by increasing the
pressure, or voltage, we also In
crease the amount of current or am
pereage in proportion.
In all electrical conductors there
is something which holds back the
flow of current or offers resistance
to it. The amount of the resistance
Is expressed in ohms.
The relationship of these different
electrical factors is expressed In
what Is known as Ohm's law. The
pressure In volts divided by the
resistance in ohms will equal the
amount of current In amperes. If
any two of the factors are known
and the third is desired. It can be
easily obtained by using this
formula.
When we have a certain pressure
setting a certain amount of current
to flowing an amount of power Is
being expended. This power Is ex
pressed In watts. Tha watt is the
product of the pressure, multiplied
by the amount of current.
With this formula, as In the other.
If any two of the fsctora are known
the third may be found easily. ,
"ADAPTER" MAKES PHONE WIRES SERVE
AS ANTENNAE FQRRADIQ RECEIVING SETS
Puget Sound Telephone Company of Everett Offers to Patrons Use of New Device Invented by Seat
tle Man Construction of Aerial Wires for Radio Reception May Be Made Unnecessary.
RADIO QUERIES AND ANSWERS
Idttor Radio Waves and Ripples:
X. Would yo a kindly oalwe me hr
ndtcc a hookus f some STra le
nroea lAe tumnc of a shert wave re-
aerative set eoasistlng of two v rlo
neterev a vmelo-coopier and one stase of
d!o frequency!
1 Would shortening the distance he
ween the rotors sad the staiors ot the
arlometers helsT
a Contd a variable condenser be uee.i
a lacreeee the elreoslh vf the aisaa'.s IB
aw circuit ana so. wot
W. eV. Chit wood. Or.
F TOUR" regenerative set is cor
j rectly constructed. It should be
ver- sha.ro In t'.a tuning. Sug-
st that you place a variaote cui.
Is thts ljrp of antenna suitable for
raJU.pno:ie? ft O. U . Portland. Or.
1. The rotor is generally three
Inches thick and three and three
quarters inches in diameter. The
small ribs at the edge of the rotor
are made 1-1 Inch high and 1-1
inrb wide. For a plate variometer
4i turna of No. IS aire wound on
the rotor and the same on the stator
wi.l give you a good combination.
For the grid variometer wind the
rotor with S turns of No. 22 and
about the same on the stator.
2. Any blade switch of 0 am
peres capacity will do very well.
1. The V-shaped antenna should
enser in h. aer... circuit in series , HZ fee Hong Con-
ith the primary ti me j thl!, iead-ln- wire to the bottom
oupler. This will sharpen the tun- I of ,h, v
. - ..;i...kt- " !
i constaeraoiy. i
'o. Such urocedure would tend !
o do the opposite.
J. .v condenser does not Increase
1 strength of the signals. The use
f one la the circuit will allow a
.ner adjustment of the circuit's ca-acity.
.tllor Radio Waves aad Ripples:
I. What can be dona for a rnea
te hookup that woa.d stop howling on
o meters? My srid and p:ate leads are
.t rlnae ,;oIher. 1 think that the
wling lavraued by the Cioee coupling
' my variometers.
; Would a tube that works on more
B ' tvattery howl more than a tube that
m less?
. Woo d a bad -B- battery cauaw
ime bowilng?
4. In Armstrongs super-reeeoerattve
eok-op. should the eeconoarv ot ID
eond counter where tnefirimary is ran-
cted to the srld of the second tub, be
r-p4 as well ee having a vartaDie cod
cev across it T
5. Kow mane tarns on both for 15 to
V meter workT
Does the above hookas ampUfy
adtophose as well as spark station?
t. May the two lubes In the atmve
oknr be lit by the iuii "A" battery?
S Can seod reaalts be obtained ea t.
W. with aa ordinary areuad laataad ot
eovaterpoiee?
T. X. X-, Portland. Or.
1. Tha causes of bowling and Its
Umlaatlon ara taken up fully In an
rticla in thia week's radio section.
Not always. The howling Is
arely caused by the tuba Itself but
due to poor battery, etc
. Tea.
4. No; tha inductance are fixed.
5. Tha primary coll consists of
J 00 tarn, tha secondary of lzi9
urn a.
. Tea. .
7. Tea.
t. Tea. Good reaults can often be
btalned with a regular ground. It
a a matter of experimenting to see
vhether the ground will work as
Ivell as tha counterpoise.
Miter Radio Waves and RiPeUs:
1 Would It ba ail right If I need
l-md speaicer with a varuora tube,
s.d condenser ana tatting eoliT
3. If en. would It b aU right te ue
ox Colainbla Orafonola aa a lend
email
. How far can I be able to hear with
V loop aerial tuning ceil and fixed eoa-
siieirr A. ras, Laanton. ur.
X, It la doubtful If you will be abla
a srt loud enough signals out of a
-ud speaker using only one vacuum
a be. Tha loud speaker works best
rhen at least two stages of amplic
ation is used In addition to the de
eetor. If you can ret signals loud
nough from your telephone recelv
rs to hurt your ears when you are
veartng them, you may bo able to
s tha sound chamber 01 tna poon
graph as a loud speaker.
1. The loop aerial can only ba used
uccessfuily with a set consisting
f at least two stages of ampllfica
tdttor Radio Waves and Rioplea:
1. Could any of tae western broed
aatir.c ataiioiu be picked op by a station
rate! at Faedlatoo with the almp.e re
nerattve receiver described In The
ren:an ef Jane 4?
2 Wouid a (rid leak Improve Hie set
i la the wire from the "A" batterv
the around connected with the wire
t:n from the phones to the variable
ndenrT K. Miava.e. ma
1. Picking up the western stations
rom Pendleton will depend on many
ther conditions besides the receiv
es set alone, such as heighth and
nd of aerial, type of ground used,
lose proximity of power lines snd
cal atmospheric conditions.
I. Yes. the grid leak is necessary
cr the successful funellon of the
acuum tube.
. Yes.
Kdttor Radio Wtm and Rtppar
1 When I connect mv receivers to the
aertal and the around there Is a contin
uous rirctne. What la this and what is
the cure?
2. Please send me a hook-up of two
honercomb coils 11-plal tariabie con
denser, and a eryjstai detector. 1 en -cioe
stamp and envelope for same.
a Could I receive from Portland with
this set; The distance la -S miles.
4. Can a sood varlo coupler be made?
If so. how. aod how sha:l I hook -it up?
A. E. O., Forest Grove.
1. What you hear Is the induc
tion set up by nearby power lines.
The only way to overcome this Is to
place your lead-in wires as far away
from the power lines aa possible.
I. The hook-up has been mailed
to you.
I. It Is doubtful
be able to hear 25 miles with your
set. Would advise the use of a good
loose coupler Instead of the honey
comb coils, as the fixed colls are
not suitable for crystal detector cir
cuits. 4. This column Is too limited in
space to take up the construction
of a vario-coupler. It will be taken
up in the radio aection In. a future
issue.
. : - , ,si
. , ,,. '7?:.,' I ' - .
: '""!' V" ' K"" ' i
I sLljiLMawawwawawwwswaaa
I
lavealor Wlghtaaaai llatealng la by wee- of his radio adapter while aa ordinary conversation la going; on over
the telephone. i
it is best to mount the binding posts
cn the rear of the panel on fiber
strips. - The large meter holes may )
be drilled with a regular expansion
oit. .
First smooth the wood off with I
sandpaper; then purchase a pint of i
dark metal primer, such as is used I
by automobile body painters. After
V U U llSLVe O Li a-l UCU LUC ll liuoi
througrh cheese cloth, give the panel
a good, heavy coat and leave it for a
day to dry. Then rub it with a very
fine sandpaper, always rubbing it in
the direction of the grain. Now give
the panel another coat of primer,
applied in a room where no dust will
fall upon the panel. This second
coat should be applied very thinly
and evenly.
A wooden , panel, is not recom
mended for an amplifier.
71
Radio Notes.
HOOKUP OF NEW ARMSTRONG
SYSTEM IS VERY SIMPLE DEVICE
Super-Regenerative Receiver, With Which Amplifications of 100,000
' , Can Be Obtained, Not Difficult to Install.
PIXIKT S
Wash..
of aerl,
Editor Radio Waves and Ripples:
1. I have made a variometer with B0
turns en the primary and i'S on the
secondary. Will this do with a crystal
receiving set for radio phone work 7
2. Which Is the better, an aerial
grounding switch or a protective device?
S. txes It spoil a tuning coll If the
enameled wire gets loose?
4. Some dare I hear Portland well and
other davs I can barely hear the sta
llena. What does this mean?
W. W., Corvallla. Or.
1. Tou wil have to have the
sam number of turns In the sec
ondary or rotor coil as you have in
the primary or stator coll to get
any results.
2. The protective device is con
sidered the best, as It works auto
matically. I. Yes. This will cause slight
change in the tuning when the wire
vibrates.
4. This Is due to the changing
atmospheric conditions, which are
never the same two days in succes
sion. However, such difference in
the conditions will not be so no
ticeable during the winter months.
IXIKT SOUND BUREAU. Seattle,
Aug. 12. Construction
ial mires for radio recep
tion may be maife unnecessary and
the questionable use of the electric
light and power wires prevented by
means of an "adapter" that can bo
janacnea to teiepnsne boxes, wnicn
will make telephone wires serve aa
safe and certain antennae for radio
receiving sets. Use of this adapter
and connection of a radio receiving
hether you will! set does not In any way Interfere
with regular telephone service.
The adapter is the invention of
Merle J. Wightman. an electrical
engineer, who is president of the
Seattle Radio association. Its serv
iceability has been worked out and
proved In collaboration with Major
Garrison Babcock. Inventor of the
telechronometer. who Is also an
officer of the radio association.
Everett, scene of the first experi
ment In measured telephone service
by means of the telechronometer. Is
also to have first opportunity to
listen In on radio over telephone
wires by use of Air. Wightman's de
vice. The Puget Sound Telephone .com
pany of Kverett. with the conaent
of the state public aervice commis
sion, is offering the use of the radio
adapter to all of its patrons. There
Is, of course, nothing compulsory
about the matter." It is a service
without profit to the telephone com
pany. Telephone subscribers wish
ing to have the adapter installed
have to become members of the Se
attle Radio association. ' paying the
regular dues of J5 a year. The tele
phone company, by contract with
the radio association, undertakes to
install the adapter on the request
of any subscriber and to see that
all users of the adapter are supplied
with the weekly bulletin covering
the broadcast programmes of the
ensuing week. This is done without
cost to the subscriber beyond the
annual $5 association dues.
The "national board of insurance
underwriters. according to Mr.
Wightman and other officers of the
radio association, has held that the
use of aerial wires for radio recep
tion Involves some hazards; but still
more serious objection has been
raised to the connecting of radio
receiving sets with high-voltage
light and power wires. The com
paratively negligible voltage of
telephone wires eliminates the pos
sibility of objection to the use of
the adapter.
The adapter itself consists of a
condenser, triangular in shape, twoi
inches to the side and half an inch
in thickness. This is connected up
inside the telephone receiving box
and with the radio receiving set.
Any receiving set may be connected,
permitting the present wide range
from simple home-made devices to
the most costly apparatus.. The
adapter or condenser does not im
pair or interfere with the ordinary
uses of the telephone. , On the con
trary. Mr. Wightman maintains that
its use will tend to steady telephone
circuits against any sway current
or unbalanced Induction.
The Seattle Radio association has
a membership campaign well under
way covering the whole Puget
sound region. The declared purpose
of the association is to establish a
broadcasting station of the best and
most modern equipment, capable of
a wide range of service. The asso
ciation officers believe that the
telephone ' wires offer an ideal dis
tributing system. The first con
tract offering use of the adapter
was made with the Puget Sound
Telephone company of Everett be
cause this is an Independent con
cern. The adapter and its possibili
ties have also been brought to at
tention of )ocal representatives of
the Bell telephone interests, and en
couragement - of its general use .Is
under consideration.
Mitor Radio Wavea and Ripples:
t. Hw mnch weald a regenerative
.--tver cost me tf I made the varlo--.eters
and the vano-coupter mreelf?
3. ouM 1 hear Waahincton and Call
raian aiatioas oa ttls set
S Wouid a copper wsra No. 14. TS feet
cik and buried atwat S inches In the
-iun't make a better around than a
atrp;pe7 J sv. Portland, or.
1. Such set. including a storage
attery and telephone receivers, will
oat you about 135.
J This wl!l depend on tha heighth
nd kind of an aerial you will uae.
he proitmlty of power lines, close
rs ef tail steel buildings and local
Ltmosrheric conditions.
. No- The water pipe Is the very
st ground you can find in the
ty.
Editor Radla Waves aad Kinpies:
1. I wish to make a variometer. What
re should the rotor be fir the best re
j.ta on short wae re-epton?
2. Can an amateur make a ltrbrninc
wlrh that wt-i pas the laaurance re-
uire meats f
a. X am incloaiag
Editor Radio Wavea and Ripples:
1. When I put a phone condenser
across my telephone receivers tha sig
nal are cut down entirely. What does
thia show?
S. How many plates ant needed In a
variable condenser to get .OOl mfd.
capacity?
a. Is a alnsle or two-circuit Jack beat
for the detector tubs?
4. Will AO turna of wire wound en an
oatmeal box do for a single circuit
tuning coli? K. W., Uandon. Or.
1. Your condenser must be short
ed or It would Increase the loudness
of the signals somewhat Instead ot
cutting them down. Would advise
making or buying another one.
2. A condenser of such capacity
usually has 43 piatea In It.
. Use the two-circuit Jack be
tween the detector and first-stage
amplifier.
4. Yes. This will do for receiv
ing short wave lengths as Is used In
radiophone. Tap about every six
or eight turns and'eonnect the taps
to a multiple switch.
WAVE ANTENNA TO COMBAT
STATIC IS NOW BEING USED
Receiving Aerial of One Full Wave Length Necessary to New
Process, Its Length Is Nine Miles.
Editor Radio Wavea and Rlppiea:
1. I have a crystal receiving set which
has gone bad and 1 can't receive any
more alcnale oa it. Have you any eus
seetinns as to how 1 can remedy the
troubles ?
2. I am ulng a horlsontal loop around
the attic. This loop Is 3d feet long and
f"et wide and has Its ends connected.
How can I connect this loop up so thai
I can set a looser wave lensth out of It?
S- W.. Jurt.and. Or.
1. Scrape all the connectiona of
the receiver parts and solder thor
oughly. The crystal of the set may
have lost Its sensitiveness. If that
is the case It would be better to get
another and fresher piece.
2. It would be better if you leave
one end or the loop msconnectea
and connect one of the wires to the
lead In leaving the other free.
Editor Radio Waves and Ripples:
1. I want to put an antenna In an attio
43 feet long and 25 feet from the ground.
How many wires ahould 1 need to get
coed reeults with a crystal receiving set?
What kind of wire should 1 use?
INTERESTED BEulXXKH,
Portland. Or
1. Run one mire all around the
attic and connect one end of it to
your lead-in wire, leaving the other
end of the loop free.
2. Us either bare or rubbrr-cov-
ered copper wire, stze It. If bare
e ia used be sure that it la in-
'faulated from the-attic 4y porcelain!
V -k - ... - WnnhA
THE thousands of amateur radio
fana, a majority of whom are
realising for the first time what
an interference static is to the re
ception of the various programmes
broadcast, will be. Interested in
knowing what means the large
commercial companies, such as the
Radio Corporation of America, are
taking 'to offset thia atmospheric
disturbance.
Perhaps the chief means used by
the radio corporat'on is In the type
of aerial. This ia known as the
"wave" antenna, which in addition
to reducing static interference, has
greatly Increased the efficiency ot
trans-Atlantic wireless telegraphy.
In order to fulfill all of the re
quirements of the theory covering
the operation ot the new antenna.
It Is necessary to have a receiving
aerial one full wave length long, or
in other words, a receiving aerial
wire miles in length. This la
exactly what has been installed.
The aerial ' Is nine miles long
and Is supported on poles 30 feet
above the ground, one end being
grounded through a noninductlve
resistance, and the other through
a variable inductance. With this
wire the Rlverhead station is daily
receiving five different European
stations simultaneously without In
terf erence.
To illustrate the operation of the
"wave" antenna, an engineer of the
Radio Corporation of America has
drawn the following analogy:
"If we look upon the new anten
na as a' large lake and the wind
aa the static, we can get an idea
how It works. Now. suppose the
wind is blowing across the lake from
east to west. At the eastern end
there will be little r no ripples,
but as we get to the western end
the ripples will gradually increase
In si me to full waves. If the 'shore
at the western end is a gentle slope
of sandy gravel, the waves will be
dissipated and will not be reflected.
"If. on the other hand, the shore
of the lake is precipitous and rocky,
the waves will be reflected and will
disturb the eastern end of the lake.
Now this antenna, having a non-inductive
resistance at Its non-receiving
end. corresponds to a sandy
shore, because It absorbs the static
and interfering waves and does not
reflect them.
Carrying the analogy further. If
we place a stationary paddle wheel
at the western end of the lake,
which is revolving uniformly and
producing waves of a uniform char
acter, these waves will travel stead
ily forward toward tha eastern end
and will net ba interrupted by or
stopped by the wind. This paddle
wheel corresponds with the trans
mitting station and the wave i
sends out is equivalent to the
waves from the European station.
"The tests which have been con
ducted completely confirm " this
theory. When the receiving appar
atus la placed at the end which is
grounded through the non-inductive
resistance it is Impossible to hear
anything but a terrific roar to con
tinuous static discharge. Using the
wire-properly as "wive" antenna.
trans-Atlantic wireless communica
tion can be carried on without any
difficulty, despite the static."
This antenna system can not be
carried out by the amateurs because
of lack of space but the system sug
gests many promising methods
which radio engineers are busy on
and hope to solve this problem of
remedying if not eliminating static
in the radiophone broadcast enter
talnment.
Careless Operation May
Distort Signals.
Characteristics mt Vaeauna Tabes
A law May lie Chh.
D'
ISTORTION of signals in ampli
fier circuits is due to the char
acteristics of the vacuum tubes treed
and careless operation, according to
experts connected with one of the
lsrgest vacuum tube distributing
concerns in the country.
The output of amplified current
may be distorted by any one of the
following four conditions, declare
the vacuum tube men:
1. If the normal grid voltage is
positive a current will flow from
.he filament to the grid and this
will reduce the maximum value of
the voltage of the positive half
cycle Of the incoming oscillation,
resulting in distortion of both input
and output currents.
2. If the Incoming signal volt
ages are excessive, the plate cur
rent will not oscillate within the
straight Una part of the character
istic 3. If the input voltage Is not
applied to tha straight line portion
of the plate current grid voltage
characteristic.
4. If the transformers and asso
ciated apparatus are improperly
designed distortion will result.
Freedom from distortion requires
a tube having a substantial straight
line plate current-grid voltage char
acteristic at negative grid voltages.
An amplifier cannot be operated at
a normal grid voltage of 0 without
distortion, but must be operated at
some negative value of grid voltage
so that this value, plus the maxi
mum positive voltage of the incom
ing signal will not produce a posi
tive voltage on the grid.
The results from the operation of
a vacuum tube depend largely' on
the operating position on Jhe plate
current-grid voltage characteristic
curve as determined by the normal
grid voltage. This value can be
fixed by the use of a C battery
with potentiameter between the
grid and filament. These facts are
presented with the thought that
many experimenters will find it
interesting to conduct experiments
with vacuum tubes as detectors and
amplifiers using a C battery. Some
ofthe results obtainable will prove
very surprising. The vacuum tube
can be operated as a detector with
out grid condenser or grid leak by
using a C battery to locate the
operating point at the point of
maximum curvature on the plate
current-grid voltage characteristic,
a a a
The use of radio for the transac
tion of governmental business has
been demonstrated successfully by
the postpffice department. Post
master General Work announced to
day that hereafter radio will be
used exclusively as the means of
communication among branches of
the department. Great saving, he
said., will be made by abandoning
the telegraph and the work will be
greatly expedited by dependency
upon radio.
The cost of radio messages a
word, postal officials assert, is less
than one-eighth of a cent. Wash
ington station transmitting admin
istrative orders, requisitions for
supplies, reports from field inspec
tors and communications for the air
mall service is averaging 1000 mes
sages a month.
se
Bakelite and formica, are the best
materials for panels, but they are
expensive, and when it' comes to
cutting holes for meters, a difficult
Job presents Itself. A smooth,
straight-grained board will make a
neat panel.
The main objection to wood is that
Its grain mars the panel's appear
ance. As it Is not a perfect insulator.
ARRANGEMENTS have been
practically completed for the
erection of a broadcasting station in
New Tork city which is to represent
the most advanced state of the art
of radio both technically and in the
entertainment sense. The station
will have a range of 1500 miles, ap
proximately, and all of the latest
improvements In radio-telephony en
gineering will be incorporated. Tlie
Radio Corporation of America will
build this super-station, utilizing the
experience culled from the operation
of the Newark station, WIZ. of
which it is part owner, and which
will close with the opening of the
new station.
On the roof of Aeolian hall, in the
heart of New York city, which is to
be the site of the new station, two
100-foot towers " with a 200-foot
aerial will be suspended 380 feet
above the earth. Several special de
vices for transmitting both solo and
ensemble music with exceptional fi
delity will be installed
The station will transmit simulta
neously on two wave length from
the same aerial but from separate
studios. The two factions observed
in the majority of radio audience
will in this manner be served. Two
distinct programmes will be avail
able every evening, one classical and
one popular. Both programmes will
be handled separately in the two
studios but modulation will be gov
erned from a central control room.
The station will be equipped with
four powerful transmitters, two for
regular operation and the other two
for replacement in emergencies.
.
' The aerial and the ground connec
tions possess what is known as dis
tributed inductance and distributed
capacity, whereas coils and condens
ers possess concentrated inductance
snd concentrated capacity, respec
tively. The concentrated- values hold
their energy within themselves, but
the distributed values radiate and
absorb energy from the outside, -so
in order to get the maximum ab
sorption the antenna system should
consist, to a large extent, of the
distributed values. This means that
it is best to use very little concen
trated Inductance and concentrated
rapacity in this open circuit. With
short waves thia is especially desir
able, but with long waves it is not
always practical, and with these
waves a loading Inductance of quite
a high value will do little toward
lowering the efficiency. But as the
short waves are the ones that most
interest the broadcast listeners, this
theory holds true. .
For best results on the snorter
waves the aerial snouia nave a
wave - length of approximately
three-quarters of that of the wave
ength that it is desired to receive.
On this basis an aerial for 360
meter reception should be about 180
feet long, but aerials from 100 feet
to about 200 feet will do. If your
aerial is longer ithan this you will
not be able to use enough
turns in your coil to convey
t noagh energy into , your detector
circuit. When a longer wave, such
fis 1453 meters, is wanted, it is bet
ter to add a coil of iitductance than
to enlarge your aerial, as the in-
.A. .1 . i rr n 1 elrDnnth WHIlM Tint
be commensurate with the extra I
trouble.
LJL - -Ife 5r
Hook-up of the new Armstrong snper-regenerattve system, employing a
single vncuuni tube only. The constants of thes circuit are aa follows i
1 Primary of -vario-coupler. 12 Secondary of varlo coupler with
twice the usual nmonnt of tarns. 3 Variable condenser, .OOl mfd.
capacity. 4 The C battery of fonr volts. 5 Variable condenser,
.0005 mfd. capacity. Duo-lateral coll 1250 turns. 7 Duo-lateral
coll 150 turns. 8 Variable condenser, .0005 mfd. capacity. JPlxod
condenser, .0005 mfd. capacity. 10 Resistances, 13,000 ohm each. 11
Vartnble condenser, .001 mfd. capacity. 12 Iron choke coll. 100 mil
henries inductance. Loop aerial, 12 turns on a three-foot square frame.
B-battery used of SO volts.
SEVERAL hookups of the new
Armstrong super - regenerative
receiver, with which amplifica
tions of 100,000 can be obtained, al
ready have been given out to the
radio amateurs of the country. In
these hookups two vacuum tube
were used to get the super-regen
erative action.
Practically the same action can
be obtained with one tube -only, ac
cording to Armstrong, the inventor.
The one-tube circuit requires very
careful handling by the experi
menter, who will hae to learn the
delicate adjustments by experience.
It is quite likely that the proper re
sults will not be obtained until
after a great deal of experimenting
on the part of the amateur.
a e
The two large duo-lateral coils
must be In inductive relationship
with each other. It will be found
that this relationship is very crit
must be exercised in the adjustment
ical and the greatest possible care
as well as obtaining the correct
amount of capacity in the two con
densers S and 8.
. a e e
In the one-tube receiver the -super-regeneration
is accomplished by the
simultaneous variation of the posi
tive and negative resistances of the
circuit. This is achieved by a sec
ond feed-back circuit, shown in the
i
accompanying diagram under the
numbers 5, 6, 7 and 8, which ia a-d-justed
to oscillate at a lower fre
quency than the incoming signal.
The proper relations between the
positive and negative resistances
are obtained by adjustment of the
condensers S &nd 8 and the coupling
between the colls 6 and 7.
a
The grid battery as shown in the
diagram consists of two pocket
flashlight cells connected in series,
giving a total of about four volts.
The negative terminal of this tiny
battery must be connected, to the
grid. The 12.000-ohm resistances
and .the 100-mill-henry iron choke
coil are standard instruments used
for filter purposes in telephone re
peater circuits and can i be obtained
from stores handling telephone sup
plies. s - e a
It must be remembered that there
are seven critical adjustments to
be made in. such a receiver. This
fact is not stated to discourage the
experimenter, but to impress upon
him the importance of very delicate
and careful adjustment. It also will
serve to remind him that in tht
event of failure at the first or sec
ond time not to give up in despair
but try again and again until com
plete mastery of the adjustabl
parts of the circuit is obtained. The
subsequent results will amply re
pay him for his trouble.
Loudness of Signals Due
to Amplifier Voltage.
Careful Experimentation Only
Will Bring Good Results. '
Efforts to produce radio-controlled
tanks appear to be the very
latest step , in government radio
work lor the army and probably for
the marine corps material. To date
no definite plan has been evolved
by radio engineering experts, but
after the navy successfully operat
ed the Iowa by radio control the
leading scientists of the army be
lieve radio-controlled tanks are a
certainty.
Today one out of every eight or
ten army tanks has a radio trans
mitting and receiving set. enabling
this leading or control tank to keep
in close touch with headquarters
constantly and communicate by sig
rals with its fellows in battle. Such
efficient liaison would be a tremen
dous step in military science, as the
tanks could also serve as message
centers for the infantry troops as
well as spot artillery fire, and keep
headquarters posted as to "the po
sition of the advance lines. Before
the year is out it is believed that all
army tanks will be equipped with
radio communicating outfits and
that the marine corps will also have
tanks equipped with radio. At the
recent maneuvers at Gettysburg the
marines used some army tanks, one
of which was a "master tank"
equipped with radio. s
e a
Yosemite's' granite cliffs rise
straight Into the air for 3400. .4000
and occasionally 5000 feet. Yosemite
valley is literally a "hole In the
ground," and some wireless experts
riciaeeri local conditions' were en
tirely against successful operation
of a wireless station mere, never
theless, valley folk recently have
been getting news reports, weather
predictions, market quotations and
lots of good music right out of tht
air. with no other aerial than wires
strung between two of the giant
trees with which the valley floor is
forested.
Edwin J., Symmes of Alameda,
Cal., put in the first wireless set for
his own amusement and has received
messages from several core damped
and Undamped wave stations, in
cluding Honolulu and Catalina is
land. . Government authorities also
have put in a station, which will be
used to keep in touch with the out
side world.
A WORD to the amateur on am
plifers: .
Using, a two or three-stage am
plifier, it must be remembered that
the loudness of the signals depends
upon the voltage used in the plate
circuit of the iast. stage.
This voltage depends upon the
type of tube used. Some tubes will
stand from 150 to 200 volts on the
plate circuit before they will
operate at a maximum when used
as amplifiers. The exact voltage in
this regard wil! have to be deter
mined by careful experimentation.
When adding a second, and more
often a third stage of amplification,
there is sometimes considerable
whistling or howling, together with
a rasping, scraping noise. This is
sometimes due tov corroded contacts
on the bottom of the lamps a con
dition that can be corrected with a
little sandpaper.
Sometimes this noise may be
eliminated by using a separate "B"
battery on the last stage of am
plification, connecting the preced
ing amplifiers and the detector to a
common "B" battery. A condenser
of large capacity one to two micro
farads placed in shunt on the last
"B" battery will sometimes help in
this regard.
Another wrinkle is to ground one
terminal' of the "A" battery or use
this idea in conjunction with the
others mentioned previously. One
or all of these precautions will
usually cut out the unnecessary
noise in amplifier work, although it
must be remembered that any am
plification of signals also picks up
and magnifies the atmospheric and
ether disturbances in a like degree
and that much of the disturbance
at audio frequency at least, will
have to be endured.
The generally accepted theory of
the cause of "fading" is the Ioniza
tion of the ether, due to saturation
by the sun's rays. For this reason
reception invariably is much better
at night than in the daytime. "Fad
ing" at night time is thought to be
due to strained conditions in the
ether, which momentarily permit
signals to travel further in certain
directions than normal. Perhaps
the best way to explain this is by
the analogy of winds, where, due
to conditions in the atmosphere, we
suddenly get a terrific rushing wind
blowing in one direction for a cer
tain distance, the velocity of the
wind varying according to the con-i
dition. Something similar to this'
probably exists in the ether, making
reception good at one moment and
weak at another. This condition, of
course, does not affect stations
within close normalrange.
The
Store
J. E. Weed, Mgr.
The Oldest Exclusive Radio Store in Portland. Z.
USE ANTENELLA AND NO AERIAL ".
Before purchasing a Radio set consult an established radio store
where you get the benefit of years of experience and service
afterward. We carry all the leading makes of sets and parts
for making them. SEIBT PHONES FOR LOUD SPEAKERS.
Mail Orders Filled Promptly. Write or Call for Catalogue.
310 Oak Street Portland, Oregon
Do Your
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Shopping
With Us
Complete Sets
and all
"THE MAKIN'S"
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ervice
We give the very best of
service FREE to every
one who buys their radio
set from us. You are
then protected by buying
from us. See our new
one -control, three -stage
receiving set which has
automatic battery con
trols and can be tuned in
less than a minute.
t
Radio Service Bureau
GASCO BLDG. MAIN 4538.
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ELECTRIC CO
Operating KQY
75 Sixth St., Portland
Radio Sets
of all kinds, made to your order.
Complete sets in stock. Large
supply of parts.
SMITH-McCOY ELECTRIC CO.
64 Alder St. Main 8011.
HIGH-GRADE
RADIO SETS
COMPLETE LIXE OK P.IKTS
M. J. Walsh
ELECTRIC CO.
106 Fourth Street
PORTLAND, OR.
J
SURE WE HAVE
Sockets for the
PEANUT TUBE
TUBE $8.00 SOCKET $1.00
Use a Standard Rheostat
ONE DRY CELL.
HALLOCK & WATSON
192 Park St., Portland, Or
"KGG" The Journal's Broadcasters.
E. L. Knight & Co.
440 Washington St. Near 12th
RADIO SETS AND PARTS
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