THE RODINA-47 RECEIVER

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP80-00809A000600300272-6
• Release Decision: RIPPUB
• Original Classification: C
• Document Page Count: 3
• Document Creation Date: December 22, 2016
• Document Release Date: September 7, 2011
• Sequence Number: 272
• Publication Date: April 21, 1950
• Content Type: REPORT

Sanitized Copy Approved for Release 2011/09/08: CIA-RDP80-00809A000600300272-6
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CLASSIFICATION CoNFiDErrrIACON[IfEfiTIf}~e
CENTRAL INTELLIGENCE AGEN~JICYYtf ! G1fl1DEPORT
INFORMATION FROM
FOREIGN DOCUMENTS OR RADIO BROADCASTS CD NO.
COUNTRY USSR
SUBJECT Scientific - Radio receivers
HOW
PUBLISHED Monthly periodical
WHERE
PUBLISHEDMoscow
DATE
PUBLISHEDApr 1949
LANGUAGE Russian
THIS DOOOY[IIT CONTAINS INIDN.ATION AUICTIN( THE NATIONAL DEFENSE
01 THE UNITED BI TES Y TNIN THE YEA-6 01 IIIIONAEE ACT 0
I. I. . 31 AN0 I[. AI A...DED. ITl TNANSNINSIOH 00 THE NITELATIDN
01 Iri CONTINri IN A.1 YANY[N TO AN UNAUTHONIIID PEN lI INO
HUITED AT LAY. NIRODU CTION 01 THI. ION. II INOHIN.T.D
Radio, No 4, 1949,
DATE OF
INFORMATION 1949
DATE DIST. t I Apr 1950
SUPPLEMENT TO
REPORT NO.
The Rodina-47 receiver, also sometimes called the Elektrosignal-3 is de-
signed on the pattern of the well-known Rodina battery receiver. It is an
all-wave battery euperheterodyne, .orking on small, 2-volt tubes. its wave
bands are as follows: long wave 2,000-732 meters (150-410 kilocycles); medi-
um wave 576-200 meters (520-1,500 kilocycles); short wave 70-25 meters
(4,300-12,000 kilocycles). Intermediate frequency is 460 kilocycles. The
first stage of the receiver is a converter (an SB-242 tube), followed by two
IF amplifier stages (21(2M tubes). A diode detector and preliminary audio pre-
amplifier are combined in a 2Zh2M tube, in which the cathode and plate are
used as a diode for detecting, while the cathode, control grid, and screen grid
form a triode for audio amplification. The two-stage output cascade (2Zh2M
tubes) is connected to the preceding stage through a transformer.
There is one IF band filter in the receiver, inserted in the plate circuit
of the converter. The IF amplifier tubes are connected together through self-
contained circuits using capacitive coupling. The receiver has a Type MN-5
neon indicator lamp connected in series with a dropping resistor which assures
proper filament voltage.
There are a few basic differences between this and the Rodina circuit. The
main ones are as follows:
1. On the receiver input, there is an LC series filter, tuned by means of
its core, which by-passes to ground any signals near the intermediate frequency.
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STATE
ARMY
1 )(1 FBI
DISTRIBUTION
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2. The method of connecting the dropping resistor to the filament cir-
cuit differs. In the dodina receiver there is a separate terminal for ccnnec-
ting the filament battery through a supplementary resistor. The positive wire
of the filament is connected to one or the other of the terminals, depending on
the voltage of the filament batter,-. In the Elektrosignal-3 receiver, there is
one termiuai for the positive filament wire, and the supplementary resistor can
be short circuited by means of a tie piece provided at the rear of the chassis.
3. A third difference is the provision of outlets for connecting an ad-
ditional loudspeaker. These outlets are carried out in the form of two symmetri-
cal leads from the primary winding of the two-stage output transformer.
4. A fourth difference is the negative feedback in the output cascade.
The negative feedback voltage is applied to the control grids of the output tubes
by means of an RC circuit. At low frequencies :the ~ negative feedback will be
stronger than at high frequencies, thereby accentuating the high frequencies and
attenuating the low ones.
The receiver output is about 0.2 watt. The filament current is 0.5 ampere
at 2 volts; plate current at 120 volts is 8 milliamperes. The receiver operates
stably with plate voltages of 80-160 volts.
Merits and Defects of the Receiver
The changes effected in the circuit of the Elektrosignal-3 receiver as com_
paredr i does away prototype, the Rodina receiver, are fully justified. The input
way with some of the interference. The negative feedback helps de-
crease distortion, and improves reception quality. Replacing the superfluous
terminal for connecting the A, battery by a tie piece which short circuits the
filament resistor somewhat simplifies this phase of receiver operation.
Finally, one must welcome the outlet arrangement for connecting the addi-
tional loudspeaker, which considerably adds to the usefulness of the receiver.
The connection of additional loudspeakers (the receiver takes two extra loud-
speakers without difficulty) enables two rooms or a house to be radiofied. This
is extremely important under rural conditions.
Moreover, the existence of this outlet enables the dynamic loudspeaker of
the receiver to be used in conjunction with a radio rebroadcasting network. Thus,
if such a network exists, there is no need to waste the batteries listening to
broadcasts which are carried by the network. Furthermore, better reproduction
can be obtained tLar by using the loudspeakers ordinarily provided for these net-
works. Finally, if the dynamic loudspeaker fails, the receiver can be operated
with an external loudspeaker. All this is very important and the plant fn-ot
identified7 did well to provide the receiver with this outlet. The need for
this extr.- pair of jacks can be judged by the fact that when the Rodina receiver
was first produced numerous queries were received concerning the methods of con-
necting an additional loudspeaker.
One of the structural differences in the Elektrosignal-3 receiver is that
the batteries are not in the same cabinet with the receiver. As is known, in
the Rodina receiver the batteries are placed inside the cabinet, but this can-
not be reckoned an advantage. In the first place, it must be noted that the
batteries usually used for this receiver (BNS, MVD-500, and BS-70) do not fit
in the cabinet. Moreover, the fumes generated at the galvanic elements have
a deleterious effect on the assembly. Many users have complained.
Although many improvements have been made in feeding the receiver, the
plant has not adequately solved the problem of connecting the receiver with the
2 - Al kn!?jTi
CONFIDENTIAL
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batteries. The ends of the leads are bared of insulation and have to be connec-
ted to the battery terminals in the most primitive fashion. This arrangement
is not mechanically durable -- after being connected a few times the ends of
the wires break off. It is also bad from an electrical standpoint, because the
surface of bare wires is always covered with oxides which do .ot come cuff when
the wire is hooked up. Moreover, the twist method of joining is slovenly in
appearance and dangerous as regards short circuits. Radio listeners do not al-
ways insulate the twists, and short circuits between the bare parts of the wire
are quite possible. There can be two results of short-circuiting: damage to the
battery or burning out all the tubes. We find it difficult to say which of these
It must further be stated that the EIS-3 does not have all the features de-
sirable in a receiver of this type. A socket for a crystal and telephone set
for listening to powerful nearby stations without wasting the batteries would
have been useful. It would 'he a good thing to fit an adapter input to the re-
ceiver. It is needed in many cases, for example, for using the receiver ampli-
fier to amplify rebroadcast network programs if they are not loud enough, for
operating from a crystal receiver, etc. The designers did not do all that could
have been done regarding such conveniences.
In conclusion, there is one more point to be made. The Elektrosignal-3, like
the Rodina receiver, is a six-tube battery-fed superheterodyne and can be regarded as a
"heavy" receiver. "Lighter" receivers are also needed. The country radio lis-
tener is now forced to choose between a crystal set and a heavy, six-tube all-
wave superheterodyne, i. e., between two extremes. Industry does not restrict
itself to producing bicycles and gleaming, multiseat ZI3-110s. IT also produces
motorcycles of various types and the Moskvich and Pobeda light cars. The rural-
radio-receiver line should also have its Pobedas and Moskviches.
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