New-York tribune., 1922-12-31
Novel Single
Tube Super
In Suitcase
Princeton Man Builds a Sci
Which Reproduces Loud
Signals While He Walks
Along Through Streets
Aerial Wound Round Box
Has Capacity Coupled Super
Audible Circuit TO Make
lis Portability Possible

Wff - prOOhDig oht " t"N f""r,
unique slrglc tube supcr-regeneFato,fiis
set constructed mas been built oy W
+ tan b Roberts. Of Princeton On'Ver-
sits % 70 unique because ~ ordsr
10 render the set portable VT. Roberts
/ has modiacd The supcr-Rudible circuit
by a capacity coupling, 20 mat ~ ~
I rot necessary 90 have an adjustable
.rduetive Relationship between the iNo
large duo-latcral cola.
The set has been constructed "a
ANAL case which can be conveniently
carried in ;hc hand. and i. is much
smaller than the ordinary suitcase.
Ths loop aerial is wired on the outside
sdros. Two houcycomh coils take the
place n! the regulation var.ocoupler
for the purpose o. obtaining q feed
back. The whole set. with batteries
complete. weighs only twenty pounds.
( The coupling between the two feed
l baex coils can bc varied by opening
and closing tlie I'D Of the case.
Thc novel part Of The sct is the
fact that y can be carried IN the
and whiio walking down Ge street
and ttill record strong signals over
ranges a. great as those obtained With
q good sized serial and an ordinary 70
yvL-rEtiyo receiver.
Dry Cell Battery Used
-hs tube used IS Y. 7. I. and .tR
niAmen; Is operated By four dry cells
arranged IN series parallel This -
suHc!cnt 90 operate tho set FOR quite n
considerable time. The "R" batteries
arc OF tho small type for convenience.
In connection with ;hc tuning n this
set, Mr. Roberts says: There arc only
tRo adjustments provided beside the
hiamcnt rhcosta,-the tuning con
dsnser and the radio-frequency feed
back. Neither OF these Is at oil critical,
except for signals that are 100 weak 20
be satisfactory anyway. Construction
s. simple and finished building the
whole thing IN less than two days from
/ the time ] commenced 20 design IL.
"It was designed COR great portability
aad has been very useful In observing
,,gnal strength ln different places,
tueh az going through the Pennsyl-
yaniG-tunnel into New York, inside and
/ outside Of steel bulldingt, near large
/ lightning rods, tuned and untuned
herials, and 90 on.
"The daytime range is about the
same as the single tube TeGenerntive
circuit on an aerial. J hear the metro
politnn stations and thc Philadelphia
stations loudly-well enough 20 work
/ loud speAker-and Schenectady fairly
we'll. At night got Chicago and At
J lGnta regularly, and Davenport. Iowa.
/ and Havana, Cuba, at times os well as
numerous intermediate stations
/ Capacity Coupling Employed
In order TO eliminate the necessity q
varying the relationship between the
two large honeycomb coils Ar. Roberts
has employed q capacity coupling 20
rs 90 make real portability possible.
This Is accomplished by shunting a
fixed condenser OF 00i capacity com
pletely around both coils The Two coils
are IN turn each shunted With .OOl
fixed condenser: but. a. be points
out, in case other tubes than tho V. T..
J are used Il will be necessary 20 have
a different value condenser scross the
80 y. Z. coil. While capacity coup
ling Is not recommended for ordinary
purposes, II ful6lls It's purpose very
sstisfactosily in this respect.
An Interesting point In connection
with the unique set Is tho fact that
the fixed condenser across the tele-
phones runs as high IA capacity as
90 microfarad.
Tho set has proved TO be extremely
steady and reliable and Mr.. Roberts
says that the tuning Is so stable thai
the la Of the box cal be shut and toe
ret carried around IN Princeton during
the daytime while listening 10 WIZ. ~
Newark.
, Aerial Can BE Used Vn Super
in describing MS set Nr Roberts
lakes me 10 t6sk regarding the uso Of
an aerial With tho supcr-fegencrstoT.
lie says: This can be done and wotks
. well. Take any super er-rtgencfstive set
with or without a loop. and connect the
, grid of The tube through a very small
capacity (fucL as ,wo coins separated
by q piece of papeIl 20 the aerial, or
ground lie aerial and merely bring the
-et near. Iu1g the capacity coupling
md = yngie tube. an engineer IN the
4. f. end 7. COMPANY hof heard every
thing east % the Mississippi while sur
rounded by Li!is in the Adirondack.
"FOr nearby stations tho aerial is
20 help Gi sli in New York Use "a
l!teen-'lch loop. TIE same circuit as
in the above descriDed portable set. a
=. r. II tube knd 10 D 'oui speaker
fwithout its transformcrl aud &c; vol
] ume sgough % be heard clearly and
with good quality 80 over thr mouse.
without ufinC any batteries a. all. The
housa current is iO D. g. sid supplies
the plate voltage and ligi.. The fis-
ment both at once. using carbon lamps
.n E.Ties 20 keep the current through
thc alsmeHi do"a 60 is rated value.
For nearby stations the resllts afe no
tcttrr ~,td big loop or even az
aerial