New-York tribune., 1922-06-18
Loop Barrage
Will Reduce
Interference
lLoop Used in. Conjunction
With Aerial Eliminates
Interference Except in
Direct Line of Station
Good for Short Distances
Should Only BE Used
Where Static l. Bad. and
Only on Regeneraiive Sets


...,,.rerce can be eliminated or re-
-, Can interference from wireless
.,r,ph stations be eliminated with
.sr,ry apparatus now in use These
!. sues,ions which naturally interest
"a, fans everywhere, and II is my
..-o,s in this article 10 describe one
.,..ot By Which Interference can be
..s5srsb.y reduced IL is known a.
=, ssrrsge system.
n, ,ogrse b.. has already been pointed
IN MS story that Armstrong; new
-..,.reeeneratve circuit completely
.,a oui an telegraph interference
49, .fark stations. and also cuts out
-. 'hrr so rer cent Of static. IL
lca4trr be considerable time
80, ,te now system can be placed
-.-ersf r.a because of manufactur-
100 other coud.tiors. IN the mean
80 ue have COZ 90 continue using
..- rresert apparatus.
= areas where there is large
.-.--. o. interference. therefore, the
..s-o- wa desire 20 achieve Is per
....fe.t described in ;he words used
r-rs. r Vs. A'cyanscrsor IN a
e..r.rai PAPER describing his develop
-.,. % t,e barraec receiver. when ne
s..
snrlnr Whisper Above q Whistle
.7,rs,r.r speaking. she correspond
a-.-e.r.. ..r. r sound waves would ee
.tsrs a~ e.r which could De- so ad-
..,..4 .t-. person could stanl close
e., s,ssr whistle without hearing the
,.r'e hnt could listen 90 a person
,~sssr from d distance of a Few
i.-iffl feet
.rsrrr .re pa- the same problem
,-,,,r.,f tts.f again in form which
80 or rew solution Distances
A., s-'y relative. end steam whistle
l,,t.fi Germany might make slch
,..se shat - would completely droNn
r.i M'a .r England ara France me
,,s-3 of pho tu.cc calling from Amer
Nov .s.. s .as, tho condition q
r~s ado fans wro live distance
f.- ,.s r.sres. h-.accastinr station,
t.. -s-- c.o.. -o wireless t'legi apn
,..-t,. even though ire latter may
,.fttt.- ,natcu-. What B., wanted
.t.,.i.., F. omcta.ns that vl.l elm
.-.s rt steam wrstIe IN TINS pay
,.,.sr a't
Car Be- Usel on Regular Sets
Its tsra.e apparatus developed for
,s-suart.c work by Nf Alexander
u- e gery CORP e. far as tne az
.t-. novice s concerned. but ~
rl-.-ea condition .t can be applled 20
Go e- Conn of re2cnera..re re-
tt.se. rsw tr Use. In ttis connection
.r I.-l.tur.rr ir ;hr Radio Primer
@ -l-f-u lowing how the system can
D. .tI-.l rtr q varo-coeEleT' W.
...sr ..-- t.r. of circuit. I1s par
-,-c.r -ar was worked oct os
H,s' E sqraao and appeared h
lr ..-a~mentnc vith sucH circal'
,,s radio enthusiast should pear one
--clt.-. t-irc .a mind. and ~ IS ,als
Ga, .t.- attempts are MADE - 'llm
.-.fs -..-fe~e-cc with present types
Of a--t-1.ss tr.~ can only oo success
g. ~ tho expense 0t tne ''s'e'
,.-s-.t, sro-, ~. station we desire t0
.f.r q. lr other H1Tes. a'ter reg &c
-- .-- Interference ere results viii D.
= .ch weaker fhnn is normally me case
.ut ~ colr.e e Is much betie! 10 n'"t
rlglc ,har lum5le o. diseof4s"'
.o.set.
Ura.r the c.rcum .tarces. therefore
+. n only ne possible o. use ine az
t-r .5arrag loop system on Iegeh-
eat receiver with Two stages o. au-
lt.fr. .ercv a~plif cation up fo qls-
..,e Cd. ffty miles from tle broadcast
~ ststor. Without the anriheatlon
20, n.r-c than twenty miles can be Oh
u.rts ft wll be Impossible % get re-
SD, web G. crystal detcc.or or nom
r.-sre--f.ec vacuum tube receiver, e<-
s5t .s .-. Sam. city that a broadcast
- station #, located. The use o.
I'D speaker is out ~ the question.
Three Additions 70 the Set
Ag.arcc ~ the diagram n the Radio
s-rsr vi'l show tnat there are three
t.fors t1 tne regulation receiver,
i,s.y. d change over switch sueh
as normally used ~ direction mo
gv0rs variable resistance IN the
i.,sara c.rcl.t and loop.
The lco7 should bee tuned for recep-
toa o. $50 meters. This can Dc Gene
b. ,srstguctng loop four feet
i'siu. eamrcsed of two cross arms
each six fcct long fastened ~ rignt
rglu % each other. Around these
u tsrrs o. No. IS copper wires are
isgnd ir such manner that eaen turn
spaced hslf an inch from the next
II. An adjustable clip Is USED ior
.sisg .n on the loop, and tnis - ias-
,sfss on wherever 81 gnals arc a. thel
r,tagos.
re charge over switch is used for
- purpose of changing the direction
, TA.cb The current flows through
~ pf.mary 70 the vario-coupler ! nls
atysTy important point as VIII oe
toyn little later.
The serial itself will naturally sup
~ nofe energy than the loop 99oss,
~; iic variable resistance Is useo ioi
80 purpose 90 striking balance pc
,fttn tro two and thus performs
'-htlior .-,t is o. the highest I'm,
l'F;al,, 90 t-e successful working oi
ns entire circuit. little TOO teehnieaI
% ee'cr.6e here.
Interference Barraged Out
ln frif circuit the loop acts in exact
ne same manner as 10 does when
.No alone So far as receiving from
~ direction toward which % Is point
u concerned However. when a loop
ssf1 alone. q. Wlli receive equaiiy
- from both directions q straight
-as-oI 90 put .t into nautical IAN
eag' Is WIFI receive fore-snd-aft but
- rhp2g'stlps When the loop is
80 with an ordinary aerial IN the
.Hese system. 70 has quite a diferent
.s'eetsfistc in that it Will only re-
we from a forward direction. Sig
- ..s coming from behind. or from any
- direction will be "barraged" out.
q, ne manner In which this takes place
- ioi.oVs: Current picked up by
~ era. travels through the primary
Hs varo-colpier in q certain direc-
80 tno ,rruces d current IN the sec
,..-.a-iy vh.ch flows In the opposite d.
y l''''. u therefore the loop Is point
n nat direction the current will