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Finnish (Swedish) spy radio sets
Kyynel (English: tear) was a range of
clandestine transmitters and receivers,
also known as spy radio sets,
devloped before, during and after World War II,
by Holger Jalander and manufactured
by the Finnish Army Depot Company Munkkiniemi near Helsinki (Finland).
Despite the fact that Finland was collaborating with
Germany during the war,
some Kyynel sets were developed outside the view of the Germans.
Some of them were supplied secretly to the
Swedish resistance.
➤ History
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Kyynel sets on this website
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So far, the following alternative designators have been identified [5]:
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VRHA M4 VRHA M5 VRHA/3 M7 VRHAB M4/M7 in cardboard box (1941) VRHAC M5/M7 in cardboard box (1941) VRHAD M10 (1942) VRHAF M10X, crystal version (1943) VRHAFB M10X, crystal version, Stella Polaris (1943) VRHAG M11 (1943) VRHAH M12/M7 (1943) VRHAI M10 or M11 in metal container
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Fix-tuned to 166 kHz (1807 metres)
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Serial numbers with the letter 'B' were manufactured in Sweden,
as part of Operation Stella Polaris [3][4].
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Kyynel is the Finnish word for tear. It was used as the codename
for a range of clandestine radio sets. Development of the range started before the
winter war of 1939, when the Army recognised the increased need for light-weight
transceivers.
Until that time, all Finnish radio sets used by the Army
had been heavy and bulky, and
were unsuitable for remote patrol liaison officers [2].
As radio amateurs already had valuable experience with radio communication under
varying conditions, the development team consisted mainly of radio hams. The
group worked under supervision of reserve-captain Holger Jalander and the initial
designs were largely based on existing German agent radio sets weighting
15kg. These developments were not very successful.
An additional problem was that suitable parts and tools were difficult to
obtain at the time.
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Nevertheless, the team succeeded in producing a small
portable radio station of which the first prototypes were tested at the beginning
of 1940.
Construction work on the radios was carried out
in utmost secrecy in a heavily guarded cottage at Lake Tuusula.
The enterprise was later moved to a better location in Röykkää and ultimately
to Nystad (Finland) [2].
Already in the early stages of the development, Jalander had decided to use
die-cast aluminium enclosures for the radios. Not only did he save on
weight this way, it also allowed the radios to be made truly watertight.
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The developments eventually resulted in the production of the early Kyynel
models M-4, M-5 and TÖPÖ (stump) which
used German valves like the DLL21 and DF11
(e.g. produced by Telefunken). For unknown reasons, only the M4 and M5
transmitters were housed in a watertight enclosure.
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The M7 receiver that was used with the M4 and M5, was housed in a regular aluminium case.
In 1941 or 42, Jalander submitted two samples of the M4/M7 combination
to the Germans for evaluation, after which the Germans copied and improved
the design, probably for their own use. The result is shown in the image
on the right.
Interestingly, the Germans had used watertight enclosures for both
transmitter and receiver. Furthermore, the devices have 4 compartments,
rather than 3, to hold a spare LT battery. The cases are painted grey
and the caps have text.
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Very little is known about the German copy, but at least one set has
survived [5]. It is currently unknown who the potential users of these
devices were — both the German Abwehr and the SD had their own devices —
and it seems likely that only a small quantity was ever manfufactured.
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In 1942, the earlier models were followed by the M-10
which was effectively
a combination of the M-5 transmitter
and the M-7 receiver. The radio set was designated VRHAG (P-12-24)
and the first wiring diagram was drawn on 13 July 1942.
A few years later, a crystal version of the radio had to be developed,
but it appeared to be very difficult to obtain crystals at the height of
WW-II.
Again, radio amateurs came to the rescue when reserve-lieutenant
Toivo Leiviskä, an electronics engineer, demonstrated how they could
be made manually [2]. This resulted in the M-10X model.
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The crystal-driven M-10X was not only used in Finland, but was
also sold to Sweden in late 1943 and early 1944. The first 25 units
were delivered prior to Operation Stella Polaris 1 in Finland, followed
by another 75 units that were produced by Major Rangvald Lautkari
in his workshop in Lindingö.
The components for this production run had to be shipped
over water from Nystad [2].
The serial numbers of the radios that were manufactured in Sweden, are
suffixed by the letter 'B'.
After World War II had ended,
production of the M-10 and M-10X continued,
as the Cold War had meanwhile started.
The M-10(X) was eventually modified and continued life as the
M-11 and the M-11X — suitable for modern
crystals — both of which remained in production until ~ 1959.
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Operation Stella Polaris was a covert operation in which
Finnish signals intelligence records, equipment and personnel
were transported to Sweden in late September 1944, to prevent them
from falling into Russian hands [4].
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The Kyynel M-5 was a watertight transmitter, developed in 1940 as
the successor to the M-4. It was commonly used in combination with
the Kyynel M-7 receiver, but could also be used with other receivers.
The device works in the 3.5 to 6 MHz frequency range and produces an
output power of 500 mW.
➤ More information
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The M-10 was developed in 1942, during the early stages of WWII, followed
by a version for quartz crystals – the M-10X – in 1943.
Although Finland was collaborating with Germany at this time, some of the
sets were secretly delivered to the Swedish resistance.
in 1944, some of the M-10X sets were even manufactured in Sweden.
➤ More information
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After WWII had ended, production of the M-10 and M-10X continued, as
meanwhile the Cold War had started, and more sets were needed for
reconnaissance, espionage and Stay-Behind.
The set was eventually fitted in a
metal container and modified for use with modern crystals – such as the
ones from American military surplus –
after which it was renamed M-11 and M-11X.
➤ More information
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- Louis Meulstee, Wireless for the Warrior, volume 4
ISBN 0952063-36-0, September 2004.
- Antero Tanninen (OH1KW), Fjärrpatrullmännens radio 'Kyynel'
Translated to Swedish and edited with permission of the author by Thomas ON6NT.
Date unknown. Retrieved, September 2012.
- Wikipedia, Kyynel (radio)
Retrieved June 2020.
- Wikipedia, Operation Stella Polaris
Retrieved May 2022.
- Günter Hütter, German copy of M4 and M7 devices
Personal correspondence, May 2022.
- Kouvolan Putkiradiomuseo, KYYNEL, "Siiri" P-12-24
Visited 11 May 2022.
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© Crypto Museum. Created: Thursday 27 September 2012. Last changed: Saturday, 04 June 2022 - 07:55 CET.
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![German copy of the Finnish M4 and M7 - Collection Günter Hütter [5]](img/DE_M4M7_small.jpg)
![Image copyright Antero Tanninen [2]](img/Kyynel_kide_1_large.jpg)
