New-York tribune., 1922-12-03
Clever Chinese
Makes Smallest
Super-Receiver
Student at Columbia Builds
Super-Set in Twelve-Inch
Cabinet With Two Stages
Of Audio -Amplification
Has Novel Switch System
Can Be Turned Into Regu-
lar Type Of Regenerative
Set by Turning Switch

The smallest super-regenerating re.
eeiver In existence has recently been
completed BY Wei Yoh WI. a Chinese
student who is taking a post-graduats
course In physics a. Columbia UNI
sersity. This remarkable piece of ap.
parstus is contained IN . cabinet
measuring twelve By eight inches and
six inches deep.
Within this small space Mr.: wu has
succeeded In placing two-tube super
rsFenerator with two stages OF audio
frequency amplihcation, the entire set
comprising four vacuum tubes. An
other remarkable feature is the system
Of switches which he has included IN
such manner that be can, at will, trans
form the circuit from super-roGen-
orator into the ordinary type Of re-
eeneratiye circuit The switch system
also includes arrangements to bring
IN az many tubes as are required
those tubes which are switched out OF
circuit having their hlament current
cut OF automatically. :. :.
The set 10 complete within itself. II
has a loop aerial measuring 10 by .
inches wired into the lid, there being
eighteen turns Of wire In II. Varia'
tion Of the induetive relationship De-
tween the primary and ticker coils Is
obtained IN a very novel manner. The
former Is wound in a little panel which
is hinged 70 the left side OF the caoi-
net. A knob working q geared wheel
which Is held IN place BY spring con,
trolls she move aJnent OF this panel, ana
thus perrrits the necessary tuning by
means Of varying the coupling between
the two coils.
Amplikers In Small Space
Tho radio Frequency ampliheation
nnIt IA contained In a compartment on
the right slde Of the cabinet, which
measures three inches In width. Inc
two tubes, the transformers and the
switehes are built into this eompsrt-
msnt with the greatest possible econ
or.v Of space. The front panel Is
bst,llte and carries nine control
The u. v. POI type Of tube is used
{, the four sockets. Only 10 Yolts
nressure is used on the plate OF eaeh
~ these four tubes. With this re-
esiver In the Columbia University radio
leborstory Mr.. WI has received the
concerts from Atlanta, Ca; Detroit,
MIsh., Pittsburgh, Chicago and several
other stations, the energy IN each case
being picked up on the ten-inch loop
only.
6fteenth floor Of steel constructed
building, signals loud enough to be re-
produced on a loud speaker were
p,cked up BY the tiny receiver from
Wol and VIZ, eighteen miles away
d.saite the fact that the building Is
ons Of the worst shielded places In
New York City. Only 4b volts were
used on the plates Of the tubes In
these tests.
Range Of Regenerative SET
The normal wave-length range OF
tie set when switched over 70 PLAN
reTensrativs circuit is 200 TO l'oV9
meters. BY means Of specially placed
binding posts however, loading eoils
can be inserted In the circuit and the
range increased 70 $4,000 meters Witn-
out any loss Of eficieney.
II took Mr.. Wu two months 70 con-
stYuct this wonderful set, working only
in his spare time at his apartment .,
West l24th Street. The workmn-saiP
is remarkable considering the iset tha'
he had no Aoequnee VIVID -
mAnd.
S,iiv MANNED and executed. In the 10
a. tbe cabinet, where the loop aerial
fs wound, there IL q schematic diagram
~ The circuit employed carefully
dr,vn and then pasted 70 the lid. This
diagram contains the constants OF
sveTv piece Of apparatus In the set.
Tho control knobs or the front are az
A. dieatsd with neatly engraved tities
and cradations shown As guioAhee
IN tuning.
Chinese Government Student
Il, Wu was born at Human, Chtnsl
ard came 20 this country nine years
sgo as one Of the Chinese government
studenss. During that time ne mas
studied at the University or Illinois
ard Cornell and IL now taking his post
graduate course At Columbia.
While demonstrating his remarkaple
act 70 me he said; II am very anxious
10 make a receiver that Will De more
compact than this. ! am going 20 Try
and construct one with the WDll tunes
which think will enable me to MAKE
the cabinet smaller. ! am sure tnt'
these tubes will work all right win
n the proper voltsges and connections
Di think there are a great many posi-
billtiss with the super-regenerstivs cir
cult"
Mr.. VIZ has unquestionably. done
great deal along the lines Of refine
ment in the super-regenerator, and his
work will no doubt have . bearing on
the development Of this system. Up 70
the present Il has been used only foI
the purpose Of receiving music and
concerts from the broadeGsting sta.
items for reproduction on loud
speaker. Tee possibilities for other
purposes. using head phones, have to
large extent been passed up because Of
the greater public interest in broad