The Washington herald., 1922-07-09
Wireless Wizard Shows
How to Avoid Static
And Interference.
OTHERS UNABLE
TO GET RESULTS
Non-Inductive Coils Used as
Noise Filter System
In Hook-up.

The invention of greatest interest
TO the radio field today is the Arm
strong super-regenerative receiver.
Amplihcation to a degree heretofore
thought impossible, the practical
elimination of interference, the
utilization of extremely low wave
lengths and the elimination by %
per cent of static disturbances were
results actually demonstrated oy
the inventor, Mai. E. II. Armstrong'
on two occasions recently. The
arst of these was the gathering or
the Institute of Radio Engineers
last month, the other a public DEM
onstration given June Is at CO.
lumbia University, within rev
doors Of the laboratory where MAJ.
Armstrong worked out his original
standard regenerative circuit.
Others Fail to Get Results.
Thu new super-regenerative re-
eeiyer is a practical possibility. IN
a few months it may be used quite
generally. For the present, now
ever. in the light of unsuccesstul
attempts of amateurs and skilled
radio engineers to attain results
conparable to those secured by ths
inventor, present apparatus shouIu
he held to with the proverbial me-
savers grip, for great will be the
disappointmen of those who scrap
their present efficient radio appa-
ratus for a radio receiver that mas
vet TO be proved generally sausIac-
tory. .,o,
Reports from several Laboratories
I'D from private expeTimenters IN
Washington Indicate that results
secured are not as startling as
those secured by Armstrong.
II this is true in washington
With its many laboratories, COM
plete equipment OF radio apparatus
and skilled hands, it may be readllS
tudped other sections of the coun-
try cannot in general be using the
new circuit successfully.
Reorire. Inventors skill.
This in no way reflects upon the
zvortb of the invention nor upon
the skill OF radio experts, out Is
undoubtedly to be attributed 10 thd'
..Iaction and combination OF ma
teriaIs and adjustment of parts
which invariably seems to require
~ Inventors touch to operate sat
tsfactorily. The/essentials of new
rsd,o svstem have been evolved
with continued patience on the
mart Of other experimenters there
x,y,I1 he available TO the whole world
tb. most advanced form OF radlo
r.ceiver developed in recent years
A loon aerial is part of the equip
nent To use the usual large an
tenna would jeopardize the appar-
atu. This indicates the amplih-
catIon secured. The second varia-
tIor from the usual radio receiver
a the c battery, giving a negative
bias to the grid.
Variation of HOok-up.
The three tubes used are five-
watt power tubes, the last OF whlch
has a plate voltage of approximately
200 volts, due to the wiring peculiar
10 this set. The first of the two b
batteries has a voltage Of 80. where
as thu battery 3, should be at least
100 and better 11O V.
TIL third noticeable character
istIc of this hook-up is what re-
sembles the filter system Of a trans
rnIttinz set. The non-inductive
coils. Fl and F2 are of 10000 ohms
resistance each. These. with the
choke coil and condenser C2,
constitute a noise alter system. In
reference from other stations than
ths one the operator desires to tune
In Is entirely absorbed.
The fourth and perhaps most i'm
nortant feature Of the new Arm
strong circuit Is the arrangement
OF and relation between the sew
eral inductances and capacities for
tuning. so that messages transmit
ted on exceptionally low wave
lengths may be received. Tuning
and variation in signal strength Is
ACCOMPLISHED by the adjustment OF