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USSR
Spy radio transceiver · USSR
SEVER 1 (Russian: СЕВЕР) is a short-wave MF/HF spy radio transceiver,
developed in 1939 by
Boris Mikhalin in Russia – at the time part of the USSR –
and manufactured at the Leningrad Kozitsky Works in Russia.
The device was initially intended for civil purpososes,
but was adapted in 1941 for military use.
More than 7000 units were manufactured during WWII in Leningrad whilst the city was
under German attack [3].
They were used by agents and by front reconnaissance groups.
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SEVER is extremely compact for its time, which is mainly due to the
fact that two of the three valves (tubes) are used in the receiver as well as
in the transmitter. It was usually powered by an external battery pack –
larger than than the radio itself – or by a mains power supply unit (PSU).
The radio is housed in a wooden enclosure and has an aluminium front panel.
The connections for antenna and counterpoise are at the right. The receiver and
transmitter are free-running, but the transmitter of the later Sever-bis,
can also be used with a quartz crystal (КВАРЦ).
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Note that receiver and transmitter do not have the same frequency range. The receiver
covers 3.62 to 12.25 MHz divided over two bands (1/2), whilst the transmitter
can be adjusted between 3.62 to 6.25 MHz. The ranges of the crystal-operated
Sever-bis version are (RX) 2.22 to 6.66 MHz and (TX) 2.56 to 5.77 MHz respectively,
and its transmitter has a slightly higher output.
SEVER was used alongside other wartime Soviet radio sets,
and was a direct competitor of the NKVD-developed BELKA
of which the transmitter worked on fixed channels only.
Internationally, SEVER is commonly regarded as the Soviet equivalent of the
British Mk VII (Paraset).
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Sever is the Russian word for North.
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Below is an overview of the controls and connections at the front panel
of the transceiver. At the bottom left is the power connector
to which an external battery pack or a mains power supply unit
(PSU) must be connected. When applying power, it is important that the
filament voltage (LT) is adjusted to no more than 2V by means of the filament
adjustment knob at the center of the front panel. When adjusting the knob,
the filament voltage is shown on the meter at the top.
The highest HT voltage (+240V) can be checked by pressing the knob
at the corner of the meter.
Headphones and morse key should be connected to the banana sockets along
the lower edge of the front panel. A wire antenna must be connected to the
A1 or A2 terminal at the right side, and a suitable counterpoise to
terminal A3. In addition, it is advised to connect a true ground — such
as the water pipes or the heating network — to the banana socket at the left
of the front panel.
At the bottom centre is the MODE selector. In the middle position, the unit
is off and the filament voltage (LT) is interrupted. In the left position, the
self-regenerative receiver is enabled. It has two bands, selectable with the
switch at the centre left. The frequency itself can be adjusted with the
course/fine knob at the top left, whilst detection is adjusted with the
regeneration control.
Setting the MODE selector to the right, enables the transmitter, of which the
frequency is adjusted with the scale at the bottom right. Prior to transmitting,
the transmitter must be matched to the antenna. This is done
by pressing the Tuning-button at the right and adjusting the Antenna Tuning
knob for maximum signal, using the Tuning Lamp at the top right as an indicator.
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- Sever
Standard version of the transceiver, released in 1941. Initially intended
for civil use. Both the receiver and the transmitter can be tuned
freely. The output power is 2W.
This version has a free-running transmitter with no provision for using
a quartz crystal.
- Sever-bis
This version, known as 'Север-бис' (Sever-bis), was released in 1942 and has the
added ability to use a quartz crystal for determining the transmission
frequency, in addition to the free-running tuning. This version has a
slightly higher ouput (2.5W) at the expense of a smaller frequency range.
The radio featured on this page, is of this type.
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SEVER was invented by Boris Mikhalin as part of a graduation project at the
Moscow Electrotechnical Institue of Communications МЕИС (MEIS, now MTUSI).
It was further developed in 1939-1940 under the project name OMEGA, at the Red Army's
Communications Research Institute НИИТС КА (NIITS KA) by B. Mikhalin, V. Pokrovsky
and I. Mukhachev under chief engineer Boris Pavlovich Aseev [1]. Once the initial prototype
batch had passed all tests, the device was named SEVER (north). Production started in
1941 the Leningrad Kozitsky Works and continued when the city was besieged by the Germans.
By the end of 1941, ~1000 units had already been produced.
In 1942, the improved Sever-bis was introduced. It had a slightly increased power
output and offered the ability to operate the transmitter with a quartz crystal,
at the expense of a narrower frequency range.
By the end of 1943, the production rate had reached 2,000 units per month.
Bt the end of WWII, more than 7000 units had been produced.
They were used for a variety of purposes, including
personal communication between front and army commanders, guerilla detachments,
reconnaissance groups, meteorological posts, geological exploration parties, etc.
Some radios carried English inscriptions on the front panel, whilst the markings were
removed from Soviet-made parts. Dit was done to misguide the enemy in case a Soviet
scout was caught.
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The bare radio measures 210 × 160 × 110 mm and weighs 2 kg (without
batteries). It has an aluminium front panel and is housed in a green
painted wooden enclosure. Power from a battery pack or
a mains PSU, must
be connected at the bottom left of the front panel.
The image on the right shows a typical Sever-bis, which has a socket
for a quartz crystal at the right side.
It can be recognised by the circular cut-out in the right side panel.
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Sever is only suitable for the transmission of
morse code signals in AM.
For this purpose the morse key shown in the image on the right
was supplied with each device. It has a fixed 2-wire cable,
with two banana plugs at the end.
The morse key should be connected to the socket marked КЛ
(KL) along the lower edge of the front panel.
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When the transmitter is used on a fixed frequency, a suitable
crystal should be installed in the two pin socket at the right
side panel. The radio accepts German crystals with two 4 mm pins
spaced at 20 mm, but can also be used with American crystals
that have two 3 mm pins spaced at 19 mm.
Currently, we don't have an original Russian crystal for this radio.
➤ More about crystals
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The receiver uses high-impedance headphones, such as the ones
shown in the image on the right. The two banana plugs at the end
of the cable, should be connected to the socket marked ТЕЛ
(TEL) at the lower edge of the front panel.
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A long piece of wire was typically used as the antenna. The image
on the right shows an original spool with 12 metres of wire, that
was used as the antenna. It has a banana plug at one end, and a
ceramic isolator at the other end.
Apart from the antenna, it was necessary to connect a suitable
counterpoise as well, for which two additional wires were provided:
12 metres (for low frequencies) and 3 metres (for higher frequencies).
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To be able to repair the radio in the field at component level,
a small set of tools was supplied, such as screwdrivers, pliers
and the soldering iron shown in the image on the right, complete
with solid pieces of tin.
Note that the soldering iron is not electrical, but has to be
heated in a fire prior to the soldering.
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In this YouTube video, Russian radio amateur Andrey Shklyaev
demonstrates (probably a replica of) a Sever radio. Several
further Sever-related videos can be found on this channel [7].
Source
Andrey Shklyaev
Date
12 March 2020
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This radio has not yet been restored. Before it can be checked and restored,
we first need a suitable power connector and a suitable power
supply unit (PSU).
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- Power connector
- Original Russian crystal
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A suitable power supply (batteries or a mains PSU) must be connected
to the 7-pin receptacle at the bottom left of the front panel.
The device needs one LT voltage (1.5V) for the filaments of the valves,
and three different HT anode voltages: 120, 180 and 240V DC.
Below is the pinout when looking into the power receptacle at the front
panel of the device.
The ticker pin at the top right is not connected to anything. It is only
used as a guide pin, to prevent the connector from being inserted the
wrong way.
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LT0 Filament (-F) HT0 HT 0V (-A) HT1 HT +120V HT2 HT +180V HT3 HT +240V LT1 Filament (+F)
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The diagram below shows how the batteries were connected. At the left
are the LT batteries, consisting of two series connected 1.5V batteries.
This provides a voltage of 3V. As the valves have 2V filaments, the
correct voltage has to be adjusted with the filament potentiometer at
the front panel, using the meter as a guide. It is best to start low
and gradually increase the voltage.
At the right are the four series connected HT batteries of 60V
each. There are taps at 120V, 180V and 240V. The terminal marked (-A)
is the 0V connection (common).
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Device Spy radio transceiver Purpose Two-way Agent-Base communication Principle Free running (RX and TX) Model SEVER Project Omega Inventor Boris A. Mikhalin Manufacturer Leningrad Kozitsky Works (Russia) Country USSR (Soviet Union) Development 1939-1940 Production 1941-1942 Range 400-700 km Modulation AM telegraphy Bands 2 (receiver only) Frequency RX: 3.62-12.25 MHz, TX: 3.62-6.25 MHz Output 2 Watts Antenna Wire 12 m Counterpoise Wire 3m or 12m (1m above the ground) Valves 2K2M, 2K2M, 2П4М (2P4M) Power LT: 3V DC, HT: 120V, 180V, 240V DC Battery LT: 2 × 3S @ 1.5V/29A/h, HT: 4 × BAS-60 @ 60V/0.45A/h Dimensions 210 × 160 × 110 mm Weight 2 kg (batteries: 6 kg) 1 Quantity 7000+ units (both models)
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Model Sever-bis Principle Free running (RX and TX), crystal operated (TX only) Introduced 1942 Frequency RX: 2.22-6.66 MHz, TX: 2.56-5.77 MHz Output 2.5 Watts
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Total weight of complete set less than 10 kg.
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- Wikipedia, Sever (radio station)
Visited 20 February 2023.
- Louis Meulstee, Wireless for the Warrior, volume 4
ISBN 0952063-36-0, September 2004
- Antentop, Soviet Spy Radio 'Sever'
Website. Visited 20 February 2023.
- Vladimirov P.A., Photographs of Sever radio
Website narod.ru. Visited 20 February 2023.
- Radiomuseum, Sever, Leningrad Kozitsky Works
Visited 20 February 2023.
- Valeria Gromova, Showcase 1. Cell 1-14. Sever bis
RKK Museum. Visited 20 February 2023.
- Andrey Shklyaev, Radio Station 'Sever'
YouTube, 12 March 2020.
- DocFilm808, Weapons of Victory - radio station 'North' 1
28 January 2023.
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No longer available in 2026.
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© Crypto Museum. Created: Monday 20 February 2023. Last changed: Tuesday, 25 August 2026 - 22:16 CET.
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