New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1922-07-02
E. Armstrong;
Epoch-Making
Set Described
Super Regenerative Circuit
Given in Detail, Together
With Complete Diagram
of Connections and Parts
First Authentic Story
Armstrong Demonstrates His
Latest Success B e fore
Radio Club of America

is destlned 20 revoIulonlze the recep-
tion OF radiophone broadcasting. was
demonstrated before the Radio Club of
America on Wednesday evening by
Major E. H. Armstrong, its inventor.
The demonstration was given in the
Havemeyer Building, Columbia Univer-
sity, a short distance from the Mar
celus Hartley laboratory, where it was
developed.
Long before the lecture started a
vast crowd assembled outside the
building, waiting patiently for the
doors to open. The lecture room, with
a capacity of 45o seats, was crowded
as never before In the history of the
university. More than 700 damned
themselves into every inch Of availa-
BILE space. while hundreds Of others
were unable to enter the hall at all.
II was some time before George E,
Burghard, president Of the club, as
sisted by Renville H. McMann, John
Grinan. William Russell and other Off
GERS Of the club, could establish suffi-
Gent order for the demonstration to
commence.
Dispensing with the more technical
language he used in the previous dem
onstration before the Institute of Radio
Engineers, Major Armstrong went into
a practical explanation of the working
Of his latest wonder circuit for the
benefit Of those present.
Before him on tables there were ar
ranged two sets of apparatus embody-
ing the principles Of his new system
and model of his first revolutionary
radio invention--a regenerative re-
ceiver with two stages Of audio-fre-
quency application. Ono OF the new
sets was arranged for the reception of
radio telegraph signals and the other
for radiophone broadcasting.
Details Given for First Time
AS result of the demonstration
am in a position to give complete de-
tails concerning the new parts and q
complete diagram Of every part used
In 1t. Under the circumstances, there
fore, purpose to outline these before
going into a description of the dem
onstration itself. The following de-
scription and diagram are absolutely
authentic and are published herewith
called Circuits and working directions
which have been published and put or
sale are absolutely incorrect.
In this particular story l am going
to give the details of the system as II
Is applied to tho reception of radio
phone entertainment from the broad
casting stations. Used in this form, il
t,,h n
fve-watt rating. The third tube is ar
audio frequency amplltier.
A glance at the diagram will enable
the reader to understand the following
description of the various parts. The
coils shown as LII and LIZ are com
posed of the primary and secondary OF
the regulation short-wave regenerative
vario-coupler. The primary is LII, but
tho secondary is used as the tickle,
coil L-2 In this case it may be neces-
sary to add few turns to the Sec
ondary in order to get the best re.
suits.
How Loop Is Connected
The loop aerial is connected across
the primary Of the vario coupler, and
it should be tuned for reception at sec
meters. A three-foot loop will answer
the purpose, but where circumstances
warrant fourfoot loop should be
used. The loop can be tuned by hav.
ing clip connection that can be placed
anywhere along one of the outer turns
In the diagram only one rheostat is
shown, but it is advisable to use a sep
arate rheostat for every tube. The
coil LIS shown between the detectol
and oscillatng valves is a duo-latera
coil of / $50 turns. Any other form OF
inductance of the same equivalent
value can be used in its place, but a
duo-lateral coil is the handiest In
form. The values Of the various con-
r densers are shown in the diagram.
Coil LA is an open core choke coil
with a total inductance Of ten MILL
- henries Coil LIS Is another duo-lat-
eral coil Of 1900 turns or Its equiva.
lent.
Filter Circuit Is Shown
It will be observed from the diagram
that there is a filter system used in the
circuit. This consists Of the resist
ances RI and Re- and the iron core
choke coil LIS, together with the con-
denser c-5. An audio-freq trans
former, marked T in the diagram, is
placed before the final simplifying tube
The values are given in the diagram.
The filaments of the three tubes can
be lighted from the same storage bat
terry, but as these are five-watt tubes,
it must be remembered that they need
seven and q half volts, therefore an
eight-volt battery should be used.
Separate "B" batteries must be used
put if the diagram is studied carefully
At will be seen that the "B" battery
Of the telephone circuit is led back to
che first battery in order that total
of from 100 TO 200 volts is put on the
plate circuit of the simplifying tube
The final detail of the circuit is the
c batteries. These batteries are used
for the purpose of putting a negative
@;as on the grids of the tubes. They
can be the high voltage B battery
type, made variable.
System Is New
The experimental who tries this set
out should bear in mind that he is
dealing with something entirely diff
ferent from what he has ever handled
before. 1t will take a little time be-
fore he is able to get it adjusted to its
best possible receptive condition, and
he must investigate the cause of
every extraneous noise he might pro-
duce by faulty adjustment.
When the circuit is properly adjusted
II gives forth clear and undistorted
music and speech with tremendous
volume, but it will be necessary to use
telephones that can stand the terrific
amount of energy passed through them
AS soon as it is assembled, and ad