I ' - ; , .
WHY NOT USE SHIELDING? 1 ' " ' " ' -- - - - -. jlj , f ' ' ; , " ' ' " ': ; V;: . ''V:'' V: .:' : ' V - "
! ' : ' . . . . - . .... . ' . - , - ' i.
1 - J ' ' ' ? " " - " " " ' ' " - , - . - - . -...' - .
ILveirroay Radio
I;
III
I
By HARRY J. 3IARX '
It seems" strange that tie arer
agelladio fan appears to hesitate
in making use of metal "B&leldtng'
when builditfg sets. Examln the
more -popular and most efficient
manufactured receiring Jets and it
'will be found that proper shielding
is incorporated in the maloirliy f
tbem Surely if th manufactur
ers ..with; theirejfpert engineering
staff find it essential. It behoore
the? fan who gonstruftts. his dtt
set) to seriously consider i i its ad
vantages. . ' f. .
Possibly the real reason for. it's
lack3 of general use, is i& the diffi-:
culty of purchasing sheet - metal
We Knar? We Don't
6utess I
At AUtdMoPe Electrical
Troubles j
r Coxn? Qct Acquainted
Joe Williams
The Battery Man
531 Court SU
-L
HSEE
' , I -
ISA
FIHE BUY
This late model Big 74
, cubic inch Harley.-David-son
completely rebuilt, repaint
ed, good tires, new 1925
lw. , 4 1 - ntlh .full Aleltlt
equipmentt. This is a machine
Priced only $185.0&.'
111
066- Harry; W, Scott
- The Cycle: Man."
Cash BAIsmo cm - . ''
Kasy Terms . .. . 147. SOUTH COMMERCIAL STREET
U.
Specialized Factory
STARfERS
W
a
w
H
-
. .
9'
AT A
-
By
233 NORTH HIGH GTIinHT-
U.
small pieces. It Is only the large
hardware supply hoiises that carry
a stock of sheet metal and these
firms are limited to the large Cit
ies.' 'Radio stores except in tare
cases are not handling shielding
material. . ) Fortunately this, de
mand is now being taken care of
andjstandardsize. sheets Jn enve
lopes like t panel stock ' are how
available, j - - -
Aluminam, copper and tin foil
Bave been placed on the, market
for shielding,itJnfortunately thin
foil stock does not readily adapt
Itself tor fastening to panel stock.
Sheet 'metal, , having some degree
of stiffness ' is more convenient.
Phone 19S
.;,:'jv-',"'WMi
" J Ji.',tn.,
STORAGE
SATTERIES j j
you would be proud to own.
, !
S. L. BATTERIES
ON
AND
'i.:.... '.fi,- ,i 1 I i ;: i j- "rV' ' 't
GENERATORS
PRICE THAT IS SATISFACTOUV
' , ' ' 3 -
GENERAL BAXTERY OR ELECTRICAL'
' REPAIR AVORK ; ,
ih'e Hour or By, Schedule as
Outlined I B llie Factory :
... S .. . 4
. .1. - -.. -,-.-..- fc, i: t-,--- V..' .-i.'
. Battery and Electrical Service
G. L. 3ATTERIE5
DT" DJMBALL '
OSINCi A'llATtCHr 1TTH TOUR RADIO RECEIVK
In connectloa ,wita radio recefvei'
and audio frequency ainplir . cir
cuits it is possible, altbongh noi'ab
solately necessary, to use a so-called
C", battery. This is tru. in. pirn
ticnlar if 4.: I or higher ratio. audio
frequency transformers are used and
if not more than 90 volts are usjed
on the plates of the amplifier tabes.
Tb use Of auch a C" battery,
usually hiring' a. voltage of from I Yi
to 4, win materially reduce the "B"
battery current consumption , and
may possibly Increase the clarity and
volume of received signals. J
The twd diagrams ilhisttate the
pktiire and schematic conneetkni .of
a C7 battery into the audio fre
quency amplifying circuit of a radio
receiver using standard FAD A audio
frequency transformers, - 't -;
With some typea of receiver and
amplifier circuits having audio fre
quency transformers with winding
ratios (or the ratio of the number
of primary tisTua to the tnnnber of
.secondary tarns other than, 4 r: 1.
there may be considerable .aignai
distortion after the signal has passed
through two stages . of audio fre-
iquency ampufication and m case no
'"C" battery is used. r Connecting
Inxed eondensers c4 trom JUWl to
U&C06 mjattfarad capdry across theartery binding post.
This can be" held in place behind
the apparatus as shown in the Il
lustrations. ' t r " , J
The question arises, which nie
tal Bhould be used. Copper Is. 'de
cidedly expensive and corrosion
makes it turn green after a time,
especially where soldering1 is done.
Aluminum has a habit of collect
ing an oxide coat which destroys
the good electrical contact. Fur
thermore aluminum does not lend
itself to soldering within the limits
of the fans equipment. . Magnetic
metals such as iron cannot ; be
used. , , ,. ,. ... -. , , ' j : . ; .
Shielding Suggestions .
For the average use behind a
variable condenser , the . circular
shield as shown on the right serves
the purpose! la cases' where some
protection between stages is de
sirable the shield with a flap, as
shown on the left in the illustra
tion, is recommended. . : t
Where shielding of this sOTt -is
used, it should be electrically con
nected to the rotor plates and on
the ground sides of the circuit.
A little more general use of
shielding will do much : toward
solving the body capacity problem
which is characteristic of home
constructed sets. ; Some manufac
turers are going to the extent of
completely lining the inside of the
cabinets in order to entirely elim
inate any possible external inter
ference. Where a cabinet is lined
in this manner the Shielding is as
a rule directly connected to the
ground terminal.
Ser vice-
H
H
W
W
f : i
;
: '
PHONE 203.
HOUTON STAKZI
I7 .0 3 ''
windifig of the - audio frequency
transformer, may . eliminate or tre-
Wuce. the transmjssion.of.the higher
noises wtucn are so unpleasant, espe
cially -whea reproduted ; by a ia
ney loud speaker. -. A '
i Higher y ratio audio : f requeocy
transformers can sometimes be im
proved in their clarity of speech and
music reproduction by connecting
across their secondary winding a
variable grid leak resistance of jjthe
order of 1 megohm. u
Some of the standard radio tre
cerrimr sets 00 the ; market have
binding posts for the connection) of
tbe "V. battery, and in some cases,
these binding posts are shorted
either bv a metal strip or by the con
netting leads. In other types of -re
ceivers. ' the connection .between
these "C battery binding posts is
left open and the circuit must be
dosed , before the receiver can j be
operated successfully. This can; be
dose either by a short wire or metal
strip, or if one desires to use the
"Cr battery, it should be connected
between the two binding posts, ma
rog sure that the positive lead from
the battery connects to the positive
C" battery binding post, and that
the negative lead from the bat
tery connects to the negative, UT
,-iue announcement by . Frepch
people that they will install
mammoth broadcasting station
that can be easily heard Ini he
united States, followed bv a alml
lar movement in Great I?ritjLln
ana tne many applications to our
ntn rnTPrntriAnt fnr in on iKh
kilowat stations, to say nothing! of
tne numerous fire kilowat : sta
tions, starts one guessing as j to
the outcome. It might be i pre-
uictea mat in a few years thre
will be a number of large stations
and no little ones at all. ,
Tbe recent drop In price lot
radiophones to $3.00 brings them
Info, the home folks class, where!
one may enjoy a delightful Coia4
panionship with them and learn io
know their accomplishments. I
' Maybe ydtl have heard Home sta
tions announce, "We give stamp4"
and have wondered whether the
announcer was "lit up" or 1 was
just harking; back to ,the days
when he was connected with
Katchum , & Sklnum's emporium
No, they are hot trading stamp
but radio's latest fad the " col
lection 01 raaio stamps. . t
In the up to date radio sbop
you may purchase the new radio
stamp album with' a sunolv of
"Proof of Ileceptl6n Cards," These
cards are tilled out and mailed to
the stations heard, who 1 In -turn
send you thelf ; stamps . These
may be put in the printed Snaces
awaiting theml -There Is Iso- a
call book and log f included. ! To
say the idea is sweeping the coun
try is puttfhg it mildly, io say the
least! ; f - "t: la"' -
Dust is an enemy of the radio
set. Put your set in cabinet-If
you can. But if you cannot, cover
it up when not In use. Clean the
dust from: between the blades of
your condensers, I ; usin a soft
cloth or bi-ush. n.' ' i I
Every bridge of poinVPf dust is
like a leak1 in the buckets i For
this same reason punched out can-
denser plates should have- theit
edges rounded off smooth.-
In Radio Digest of February 7
the Bankers Life insurance ;sta
tinn WH(1 'itTwit IfDntnM, ta . ia
delightfully described ,hy Vera
Brady snipman. - rrhe station is a
commercial one & addition to the
broadcast features. The idea was
originated and Completed by Billy
Heinz of that otganizationv Grand
Opera producers have been shy
ing at broadcast stations just like
the old mare sed -to shy at an
automobile Recently 13..radk
station owners In Boston had such
confidence t
n- this belief that
broadcasting
opera would help
further thau
aVm tHe box receipts
that they
artuatl-r -tirifirwrfitfi
the expense
cospaBf'.t'.!
I . The " '
RADIO PHAN
Talks j r
I i-1 :
1
, . . ,
ia. ' Boston - z
f a Chicago operatic j
i gusrsstsed- iiaj
1 i- -. . 1 I t rr" 1 1 v r
I-.-: I'"1!-- ' T
; ;ij r-Hr" rft : I .
-1 r- . r - . ' J- '
:,:; . .. At-
, .vjass ' y. ..:
-i
.. - t -
CORNER CHEMEKETA AND HIGH
- t . -'a - -i '
11 ri j.
1
f,i:!
against any loss due to broad
casting. . several n operas were
broadcast and lw await with un
usual interest the results.
Millions Ot Dollys 5 iki
I sent uacK From Germany
BERL1N, h-rtei.-i f 7American
currency ifent jsack ;toi tne mother
iouatry at' a record irate in .124.
During the Inflation1 period American-
banknotes! and silver ; certifi
cates and all sorts of ther Amer
ican paper money were boarded.
Frieads aad . relatives i remittc i
bls 'asi it was tucke4:awey-wr
value tlii
low cost, Chevrolet now has greater "quuty tnaii
everbefbfe' V ,
chassis from radiator to rear axle, new quality
features of construction that you would expect - to
find only on higher priced cargo
bodies bF even gteatet beauty and coinfort. Open
models have inany added refinements. Closed
models with fine Fisher Bodies
finish in beautiful colors "of the wonderful and
???g tDuP, that, retains, its color and, lustre
iiidefimtely and1 withstands severest usa :
3 2?
i i
a. rainy, djy,. yhile. .the . Cermaa
paper money wa fluctnaiins' a
wildly nobody -waiited to fcold itj.
ConseuentryalJLiortaJjXorelga
stable .money was in great de
mind and "American money wa
th, first ..choice as .Jt..fl actuated
less even t4an ifnglish pounds. 4
fow thai the" tentenmark ! ha
been fairly firm for nearly1 a year
accf Germaaa have general confii
dc nee in ltj they t are letting go
of their foreign money st a rapid
v ,.v. uiuiaus aoaraea
'torjelsn gold -or ; silver are! out ok
luqi, as the exchacger-Tate on it
Is pxtremeiy bad. Nobody wants
iiaramortey.ndLhe..(jiiC!tatIoa3.cj
f:
m
la.ofien 20: percent below the of
ficia rate for paper . money.
Foreign silver is an absolute drag
on.. the r money-, market. Small
moneychangers who will accept It
often1 shave -it 4 Oi per cent.
Insurance agent got arrested id
Dallas, Tex;, but not because of It.
5 1 fist! hi!
GreIpf nd Towing
W Gir Too Tour
t3Ieaer's Wort
. w t y
irn-fr"
1
...J t
Guaranteed Er;ert T
(I
r