New-York tribune., 1922-06-11
ronderfuI Radio Apparatus
Tells Pilot When He Is
a. Cenie- of Landing
Field During a Flight
Eliminates Danger of Fog
o.r.Ioped by Us. Air Mail
service After Series of
Persistent Experiments

i'' -.a.,t 10 those engaged in the
-" -, n commercial aviation.
-. already removed the ierrors
- ,,on aerial navigation and has
= - ,ish, flying possible. Without
-, - svine no system Of civil aerial
.''..,.r, will ever be successful.
!. ,e,n, article on this page the
= -, United States Air Mail
sols J. "a. ou,lined This service has
S..'., 81. ..r,s remarkable pioneer work IN
y, 5.velopmer, Of radio as an aaJunct
n' n'.,,.i navigation. and OF this work
= - - question that the field local
sas's :, - most important Of all
A,. y 80 thing 70 guide an airplane
-. ,srough iog 20 the place where
80 ~. ~ The machine desires TO 90
y, &c another 10 bring the ship
"a ~ - earth. This fact was demon
'.-,,ss % IN the transeon;inentai ar race
,ro years ago, when the Dig Martin
-, vas caught in a fog between
NJ. vo;nes and Omaha. Her pilot
- ~ hi. skill and judgment in
s,'-r;,y the biz machine 10 earth, but
,,~sbie n avert crash. His skill
1900 tho seriousness of the forced
isr5,rr but did not prevent the subse-
ssent crash.
Fos Chief Danger in Flying
rt.,s is no more embarrassing situa-
,io, for The pilo, o. an a!rplane than
- Re-, dense fog a. the end of his
'syrs.v without fuel. IL Is impossible
10 remain in the air, and yet he does
70, know the nature Of the ground be-
bw him. 4 crash under these circum-
es,ees Is practically inevitable.
With this situation In mind the en-
,ss4,s Of ite United States Air Mail
service started three years ago a series
4 experiments designed 90 eliminate
Ms danger from the art Of aerial navl-
.,,on. ard they naturally turned 20
nsio as The means 20 achieve their OBJ
ts;
With the experience Of the radio di-
rston finder before them. they know
IA, ele:tro-magnetic waves could be
NJ. %. In one direction with certain
iypts E. trsnsm.;ting equipment. Now
~ loz.csl inference was that II ap-
tsrl.rs could be developed which
v,.l shoot a beam Of elcctro-msg
is., waves vertically into space. a
yi.g, vosd be enabled TO tell jus;
wsta he vas over the center Of the
aiding i,d where he desired TO
s.s,i Tia lis the basis Of the radio
.s.s lssslifsr, which was subsequently
s.aitNtsl5 developed
sysftm Now Perfected
Tie perfection Of this apparatus did
rg course. come Immediately. IL
,olostd a series OF careful and per
ai.sri experiments, which at first were
.il non successful. The system, how
tlH. has now been perfected, and Will
iSs1 be IN general operation at all OF
1s az mail flying fields. IN accord
irss with tho radio expansion program
E,Ah .he chiefs OF the service are no"
1glged ln promoting.
TIE oaicial description Of the ap
rrius ls as follows: The localizei
device for transmitting radio sig
as more or less vertically. 80 as Z
.-u an electromagnetic field over TN
ring field itself, and extending L
nhcient altitude 20 enable the PHO
Intercept this zone Of sound aboy
, clouds or fog
When the experiments were mrs
tlf.el efforts 60 achieve the end u
rev we're made with current o
Ed.o frequency. Coming back 20 tn
tAeial description. We are told: Tn
tsyes consisted Of a single turn o
vHe Of fairly large diameter. Will
weather proof insulation. which wa
laid around the outside Of the hyinl
seli.
Avdio Frequency Used With Loop
In actual experiment this turn-o
lep-was $500 feet IN diameter. j
Va found that when the output o.
6,-cycle generator was supplied u
t.s loop directly with key modulstion
a. electromagnetic held was pro
elssd in the form Of cone wnos'
ara decreased with altitude. The up
ltinost effective limits Of this device
we're around 5000 feet"
Fos practical purposes this system
ru not successful. as study OF tn'
results obtained will show. As de
.nted above. the electro magnetic
fs1 above the loop aerial was in th'
.,fn Of a cone with the apex IN th'
ts.ds. Now 10 will be readily seer
"a; an airplane flying At norma alti'
is.ts would have extreme difhculty u
passing through the zone OF the elee
renagre,ic field. and II would be only
q, ntrest chance that he would nap,
~ 70 strike Il. Machines hying a
rr,,r attitudes than 5000 feet woulc
~ pass through the magnetic helc
All.
ls,rt vas another disadvantage tC
- system and Il lay in the fact tha'
y ne cone Of the magnetic held va
fst'inr upward. the width OF the heIc
Va greatest a. It's base. which OF
s'sfse, vas on the ground. This meah'
iir IS the pilot came closer and closer
y ne ground the more uncertain ne
.ese et as 70 just where the center
q re lsrdirg field was located.
An Inverted Cone Needed
i'oz this it will be seen that wha'
Us needed was an electromagnetic
20 N The shape Of cone, whose base
y IN the clouds and its apex on
srognd.
rsx; experiments designed 70
t this result were made WIN
s,a o. radio frequency. The device
'.'aiecomplish this result has been
A'tzed and is the so-cslled "held
s,ar" Reverting back to the ofheiai
s,fiion We find the following;
A device consists Of two loops
~. y. Nih a single turn. separated oy
,.-s.nee Of about twelve feet, wound
lie 70 the earth's surface. 4 radio
rtnty current is used, when
nrough these coils in opposite
= actual practice these coils are
49, sfound wooden hangar. from
t.,..s shsy are carefully insulated. As
49, raoio-frequency current is
~, N This device with key modula-
a. Inc resulting electromagnetic
Al. ut.s the form Of a cone whose
AHrTfrnrr -