RCA Apparatus Catalog

52 Pages·2015·29.62 MB·English

RADIO APPARATUS
C-Por
Amateur and Experimental Use
'JRth INSTRUCTIONS '}Oy
CoNTINUOUS WAVE OPERATION
...---- - - ' - - ,
""- - - - - - - ----,
Radio
~Corpor~tion
of. .AmerJca
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Cl~ ~
WOOLWORTH BUILDING - NEW Y01UC. -
NOTICE
T
HE power tubes and other radio equipment described
in this bulletin are sold for atnateur or experirnental
use only. Any other use will constitute an infringe
ment of the Radio Corporation's patents of November 7th,
1905, January 15th, 1907, February 18th, 1908, and many
other patents. A number of cit'cuit diagrarns are given
in this bulletin which may be successfully used for radio
transInission, and the amateur and experimenter is given
the privilege of assembling Radio Corporation apparatus
in these circuits. The amateur and experimenter may
desire to construct the simpler parts of th~ apparatus
in the circuit diagrarns which the detailed information
in this bulletin will enable him to do. The Radio CC)I'
poration is glad to extend this additional privilege under
its patents in order to develop interest in the arnateur
radio art, but these privileges are given to no one except
the arnateur and experirnenter, and then only for their
use and not for sale.
RADIO APPARATUS
for
Amateur and Experimental Use
with
Instructions for the Operation
of
CONTINUOUS WAVE APPARATUS
PRICE 25 CENTS
September 1, 1921
RADIO CORPORATION OF AMERICA
Sales Division
Woolworth Building . 233 Broadway
'NEW YORK CITY
Courtesy of the New Jersey Antique Radio Club 2015
R A D I 0 COR P 0 RAT ION o F AMERICA
CONTENTS
INSTRUCTIONAL SECTION
PAGE
FOREWORD.... . . ..... . ... ..... .. ... ............ . . . ........ . . . . . . 3
RADIOTRON TRANSMISSION.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
A SCIENTIFICALLY CONSTRUCTED STATION.. . . . . . . . . . . . . . . . . . . . . . . . . 6
GENERAL INFORMATION TO THE AMATEUR.... . . . . . . . . . . .. . . . . . . . . . . 8-9
TRANSMITTING TUBE CIRCUITS . .. . . . .... . .... . ....... .. . . .. . . ... " 10-19
THE PRACTICAL USE OF TRANSMITTING TUBES. . . . . . . . . . . . . . . . . . . . . 20
CATALOG SECTION
RADIOTRON TRANSMITTER TUBES ....... . . .. . .. . ....... .... .. . ... " 22-23
KENOTRON RECTIFIER TUBES. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
TRANSMITTER ACCESSORIES .... ... . . . . . ... . . .. .... . ...... ... . ... . . 25-33
RADIOTRON RECEIVER TUBES 34-35
RECEIVER .AcCESSORIES .. .... .... .. .. . ..... . . . . . . . . . . . .. .... .. . . . 36-44
ANTENNA MATERIAL AND ACCESSORIES ....... . . . ..... . . ......... " 45-46
THE WIRELESS .MAN'S BOOKSHELF .. ... . ...... .. .... . ... .. _. . . . . . . 47
NOTICE TO PURCHASERS . . . ..... .... .. .. . . . . " . . . . . . . . . . . . . . . . . . . . . 48
All quotations made herein are F. O. B. storeroom,
New York City, or factories, and are subject to
change at any time without prior notice. The list
prices given herein apply to the United States only
COPYricht, 1921, by Radio Corporation of Alnerica
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FOREWORD
T
HE RADIO CORPORATION OF AMERICA takes
pleasure in offering this, its first catalog, to the fraternity
of radio amateurs and experimenters. During the last few
years the trend of development in wireless communication has
been in the direction of continuous wave transmission and
reception. The only suitable method of generating continuous
wave energy for amateur radio transmission is the one which
employs vacuum tubes and associated circuits as oscillation
generators.
The manifold advantages of continuous wave transmission
over spark transmission need no longer be emphasized. Prior
theory, exhaustive laboratory tests, and current radio practice
have established beyond doubt its superiority over the damped
wave method. Starting from this premise, the Radio Corpora
tion of America, backed by the research and manufacturing
facilities of the General Electric Company, set out to develop
continuous wave transmitting apparatus which should be simple
in operation, efficient and reasonably priced. This modern
system, besides enabling the amateur to cover extraordinary
distances with low antenna power and with a minimum of inter
ference to the operation of other stations, makes possible the
transmission of wireless speech, i.e., radio telephony.
I t is believed that our object has been obtained; and this
catalog has been issued to popularize C. W. apparatus, and to
furnish the radio amateur with the data necessary for the
efficient operation of C. W. transmitters.
The Radio Corporation is proud of the apparatus which it
has developed, and is solicitous of its reputation; and in line
with this policy it will be glad to have called to its attention
any defect in material or workmanship which may be noted by
the purchaser. I t is the aim of the Corporation to serve the
radio amateur, and to establish its trademark as a symbol of
quality. Remember that back of the Radio Corporation's
products stand the splendid research facilities of its associates
in 'the field of electricity, the General Electric Company, the
American Telephone and Telegraph Company, and the Western
Electric Company.
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R A D I 0 COR P 0 RAT ION o F AMERICA
RADIOTRON TRANSMISSION
THE USE OF RADIOTRONS IN EXPERIMENTAL CONTINUOUS
WAVE TELEGRAPH AND TELEP}-lONE SETS
CURRENT literature devoted to amateur energy that can be put into an antenna at short
radio activities affords sufficient evidence wave lengths or high frequencies.
that the era of continuous wave trans The vacuum tube transmitter using the Radio
mISSIOn has arrived. It ha3 long been known Corporation's Power Tubes is comparatively
that continuous wave sending apparatus would simple, both in point of construction and in
provide a greater radio transmission range than operation. It is no more difficult to adjust and
a spark transmitter of the same power to thc to maintain than a spark transmitter, and it has
antenna, and also that the use of continuous many points of advantage over the spark set.
waves would permit the adoption of more There are, however, certain precautionary
efficient methods of reception than the spark measures which must be considered in vacuum
system. tube operation, and it is one of the objects of
The only suitable form of undamped wave this bulletin to place before the amateur such
generator for short wave transmission is the information as will enable him to secure the
oscillating vac maximum results
uum tube. The from a tube set.
expenditure of Moreover, as the
large sums of operation of the
money in pains tube transmitter
taking research be c om es better
con d u c ted b y known among
America's fore amateur experi
most scientific ex menters, it will
perts, has enabled occupy the pre
the production of mier position in
reliable and effi a mat e u r radio
cient power tubes work.
-RADIOTRONS Two prime ad
-which may be vantages of con
employed as tinuous wave tel
generators of con egraphy should
tinuous oscilla not be lost sight
tions, of any fre of; namely, the
quency used in high degree of se
radio communica lectivity, and the
tion. The vacuum greatly increased
tubc is better STATION "2ZL," LOCATED AT VALLEY STREAM, L. I. USING TWO range obtainable.
adapted to radio 50-WATT RADIOTRONS, THIS STATION HAS BEEN HEARD It is usually
OVER 1,900 MILES OVERLAND
transmission at jJossible to trans
wave lengths in the region of 200 meters than mi t two to three times the distance that can
the spark system, for the spark system has cer be covered by a spark set of the same antenna
tain inherent characteristics which place a very power, and in addition interference is reduced
definite practical limit upon the amount of to an absolute minimum.
CONTINUOUS WAVE TELEGRAPHY (C. W.), INTERRUPTED CONTINUOUS WAVE
TELEGRAPHY (I. C. W.) AND RADIO TELEPHONE TRANSMISSION
EVERY up-to-date radio experimenter wants Tubes, the amateur call telephone to the neigh
a radio telephone; he will also want a long boring stations over moderate distances, and by
distance radio teJegr:'lph set. With the shifting a few switches he can adapt the set for
same set, using the Radio Corporation's Power continuous wave telegraph transmission and
R A D I 0 COR P 0 RAT ION o F AMERICA
cover distances by telegraphy three to four times similar to those sent forth from the antenna of a
those possible by radio telephony. This is the spark transmitter. By a suitable arrangement
modern way of doing things in the amateur of controls, either C. W. transmission, 1. C. W.
station, and today there are already several transmission or telephony may be had from the
thousand RADIOTRON Power Tubes in use at same set, simply by shifting a few switches.
amateur stations throughout the United States. A few amateur receiving stations are still
The Vacuum Tube Transmitter not only per equipped with crystal detectors. In order to
mits wireless telephony, but also enables the transmit to these stations with a tube trans
amateur to make use of modulated or interrupted mitter the grid circuit should be modulated by
continuous wave telegraphy. Thus, if the energy a rotary "chopper." Such a chopper is nothing
supplied to an antenna by an oscillating tube set more than a rotary interrupter designed to inter
is modulated by a microphone transmitter, tele rupt the grid circuit of an oscillating tube from
phonic communication is possible; or if the 600 to 1,000 times per second. Tests have demon
antenna oscillations are modulated by a buzzer strated that a tube set modulated in this way
or preferably by some form of rotary grid gives the same reception efficiency as a quenched
chopper, the antenna will radiate wave trains spark set of the same power to the antenna. .
SOURCES OF ENERGY FOR TUBE' TRANSMISSION
v
A ACUUM power tube requires a low volt former should be provided with a high voltage
age source to heat the filament and a high secondary for the plate circuit supply and with
voltage source to energize the plate or two additional secondaries providing a step-down
anode circuit. The requisite e. m. f. for the plate voltage to light the filaments of the Power Tube3
circuit may be obtained in three ways: and Rectifier Valves. In addition, a reactance
and condenser must be supplied to smooth out
(1) From a high voltage D. C. generator.
the ripple in the plate current, as shown in
(2) From a rectified A. C. Source, using the Radio
Corporation's KENOTRON, or two electrode, Figure 4 of Page 14.
rectifier valves. In the third method two RADIOTRON Power
(3) From an A. C. Source directly applied to the Tubes may be connected in a type of circuit in
plate (self-rectification circuits).
which alternating current of suitable voltage can
If only a D. C. source, such as 110 or 220 voits, be applied directly to the plate circuits of the
is available, a high voltage D. C. generator tubes. The tubes then act simultaneously as
should be obtained. The motor should be sup rectifiers and oscillators, using both halves of the
plied with slip rings to provide an alternating impressed A. C. cycle. This is called the seIf
e. m. f. for the filament (through the medium of a rectification method. By means of a smoothing
step-downtransformel'). The generator should out reactance of suitable design (see Figure 2
provide high voltage D. C. according to the Page 12), the variation in amplitude of the antenna
rating of the power tube. oscillations may be reduced to a minimum value,
Amateurs having access to an A. C. source giving all the advantages of C. W. transmission.
only, should obtain an A. C. transformer and The self-rectification circuit is recommended for
two of the Radio Corporation's KENOTRON telegraph use only. A suitable D. C. source
Rectifier Valves arranged in a suitable circuit to obtained either from a Rectifier Unit or a D. C.
rectify both halves of the A. C. cycle. The trans- generator should be used for telephony.
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R A D I 0 COR P 0 RAT ION o F AMERICA
A SCIENTIFICALLY CONSTRUCTED AMATEUR STATION
By H. H. BEVERA.GE
oo
T little attention has been paid by amateurs to the ground wire system
of their radio stations. Amateurs whose stations are located appropriately
should give attention to the interesting series of experiments described below,
conducted by H. H. Beverage, Special Engineer of the Radio Corporation's High
Power Receiving Research Staff, who has found time to apply the principles
utilized in high-power commercial radio stations to amateur stations. By
following Mr. Beverage's advice any amateur can duplicate the results he' has
obtained. Mr. Beverage has analyzed and placed before amateurs the " crux"
of a successful tube transmitting station.
MANY amateurs have considerable diffi about sixty ohms to ten ohms. By combining
culty in getting a low antenna resistance, the ground with the counterpoise as shown in
particularly in locations where the soil is Figure 2, the antenna resistance was still further
sandy. Under these conditions, a counterpoise reduced to about four ohms. The resistance of
must generally be used to get the antenna resist the helix used to tune this antenna was about
ance down to reasonable figure. In many cases, three ohms, making a total antenna resistance
'1,
however, it is possible to combine a ground con of seven ohms. The above resistance values
nection with a counterpoise, in such a manner as were taken at 280 meters wave length.
to still further reduce the antenna resistance by a vVhen the circuits are properly adjusted, re
large amount. moving either the ground connection or the
In the General Electric Review for October, counterpoise connection will not change the
1920, Mr. E. E. Bucher describes the Alexander antenna wave length, but will change the
son system for Radio communication. He shows antenna resistance only. The easiest way to
how Mr. Alexanderson has combined a buried tune up the counterpoise and ground is to first
wire ground with a capacity ground for more tune to the desired wave length, using the
unifOl mly distributing the earth currents. In counterpoise alone, then try the ground clip on
Figure 1, the inductance of the helix below different turns until the point is found where
the gl'Ound tap tunes the capacity ground, the "vave length is the same as with the counter
while the inductance between the ground tap poise alone. The ground clip should be adjusted
and the antenna tunes the antenna circuit. to within a half turn on a large diameter helix.
The section of the helix above the ground 'When the ground clip is at the neutral point, the
connection may be considered positive with inductive impedance of the helix below the
respeCG to ground, and the section of the ground point tunes with the capacity impedance
helix below the ground connection may bA of the counterpoise, forming a series-tuned cir
considered negative with respect to ground. cuit of comparatively low resistance. The total
By suitable tuning, the total antenna current antenna current divides between the ground and
may be distributed between the capacity ground the counterpoise inversely proportional to the
and the buried wire ground in any desired ratio. effective resistances of the ground and counter
In the case of Station "2BML," at· Riverhead, poise circuits.
L. 1., the soil consists mainly of dry sand under With the counterpoise on the bottom of the
the antenna. There is a small pond near the helix and no ground connection, the wave length
antenna, but not under it. A good ground was is 336 meters and the effective resistance is about
obtained in this pond by running several hundred nine ohms. When the ground clip is put on turn
feet of wire into it. The 'antenna resistance No. 1, the total current divides in inverse pro
using this ground was very high, between sixty portion to the ground resistance and the counter
and seventy ohms at 200 to 300 meters. The poise reactance, and, obviously, most of the
writer decided that since the soil under the current will flow in the ground lead. Since the
'antenna was sandy, the high antenna resistance counterpoise has little effect, the wave length is
was due to the fact that the antenna flux was practically determined by the antenna capacity
forced to travel through very high resistance and the helix inductance between the ground clip
soil for a considerable distance before reaching and the antenna clip. As the ground clip is
the low resistance ground wires. moved up nearer the neutral point, the wave
A counterpoise of four No. 14 B. & S. copper length becomes shorte1:, due to the decrease in
wires running parallel with the antenna flat top inductance between the ground and antenna
and directly beneath the antenna was put up, clips, and the counterpoise reactance is partly
the parallel wires being four feet apart and care tuned out by the inductance of the helix between
fully insulated. The counterpoise extended the ground and counterpoise clips. The effective
several feet beyond the antenna at both ends. resistance decreases as the ground clip is moved
When the counterpoise was substituted for the up, because the counterpoise is taking a greater
ground, the antenna resistance was lowered from and greater portion of the antenna current.
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R A D I 0 COR P 0 RAT ION F AMERICA
When the neutral point is reached, the counter The antenn?- current is six to eight amperes,
poise reactance is entirely tuned out, and the depending upon the voltage of the local 60-cycle
counterpoise takes most of the antenna current. supply. The plate voltage is 2,000, using full
In the case of Station "2BML," the counter wave rectification with two KENOTRONS.
poise capacity was .0007 M.F.D., and the antenna The smoothing condenser is 1% M.F.D., butis not
capacity was .0005 M.F.D. When the ground clip large enough to smooth out the 60-cycle ripple,
was properly adjusted, about 75 per cent of the so the modulation is not particularly good and is
total antenna current flowed in the counterpoise seldom used, although it has been heard over
lead and the other 25 per cent in the ground lead. distances of 300 to 400 miles several times. The
With this combination, the antenna resistance RADIOTRONS draw as much as 600 watts or
wa' only about 40 per cent of the value obtained more from the condensers, so a very large con
with the counterpoi e alone. denser would be required to smooth out the 60-
Many amateurs already have a counterpoise, cycle hum completely. The maximum input in
and the writer believes if the e amateurs will the antenna with a single tube varies from 250
combine their counterpois~ with a ground con to 450 watts without overheating the tube, and
nection as described, their radiation will, in many doubtless more energy could be put in by using a
cases, be doubled, especially in cases where a higher plate voltage.
good ground connection is available. Very good The helix consists of a power line lightning
lIe/l~ fill' o/um//lum rod
1.5'd io 20/urns rod/o/lon
6-8 omps .,
Rodlolron
2sowoll
IJY204
~'M1
',Hosler OSCI/Iolor
Hod/olron {/1/-2tJ2
?ooov. Coon/erpoise
110 Y 60-
tooooooooooooool HI ClJoA-e I.S M.II.
;'
WIre ground
/lOy' 60- IIOY. 60- IIOV. 60-
FIGURE 1 FIGURE 2
re ult hould be obtained even if the ground arrester choke coil made of 21 turns of ~ -inch
ystem is not directly under the antenna, as for aluminum rod wound in cylindrical form, 15
example a water-main ground. inches in diameter. Two old 2,000-volt trans
Figure 1 is a diagram of connections of the formers are used for supplying voltage to the
apparatus u ed at Station "2BML." There are KENOTRON rectifiers. One is a five K. W.
no special features excepting the combination of 133-cycle power transformer, while the other is
counterpoise and ground described above. A a 250-watt potential transformer, both having
master oscillator is u ed to keep the frequency as a 20 to 1 ratio and both delivering the same
constant a possible. It is e ential to make the watts to the rectifiers.
conden ers in the ground and counterpoise leads The antenna is also a make-shift affair con
large in comparison with the counterpoise and isting of a small horizontal cage of three No. 14
antenna capaci~ies. The condenser in the wires about forty feet high and eighty feet long.
counterpoise lead is simply a stopping condenser Station "2BML" has been in operation for a
to keep the plate voltage off the counterpoise. number of months, and like many other C. W.
Two 250-watt, type UV-204 RADIOTRO S stations, the radiation was about one-half am
are used. One tube is used as the oscillator and pere at first, but was gradually increased by
the other as the modulator. experimentation until eight amperes was finally
7