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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 the Finnish Army Depot Company Munkkiniemi near Helsinki (Finland). Despite the fact that Finland was collaborating with Germany during the war, some of the Kyynel radio sets were secretly build for the Swedish resistance.


Kyynel sets on this website
Kyynel M-10 and M-10X
Kyynel M-11 and M-11X
  1. Fix-tuned to 166 kHz (1807 metres)
  2. Serial numbers with the letter 'B' were manufactured in Sweden, as part of Operation Stella Polaris [3].


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 components and tools were difficult to obtain at the time. Nevertheless, the team succeeded in producing a small portable radio station and the first prototypes were tested at the beginning of 1940. In the early days, construction work on the radios was carried out in the 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 [2].

Already in the early stages of the development, Jalander 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 water-tight. The developments eventually resulted in the production of the early Kyynel models M-4, M-5 and TÖPÖ (stump) which used German valves (e.g. produced by Telefunken).

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.
Image copyright Antero Tanninen [2]

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 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.

Kyynel M-10   M-10X
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

Kyynel M-10X transceiver

Kyynel M11   M-11X
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

Kyynel M-11X with battery compartment on top

  1. Louis Meulstee, Wireless for the Warrior, volume 4
    ISBN 0952063-36-0, September 2004.

  2. Antero Tanninen (OH1KW), Fjärrpatrullmännens radio 'Kyynel'
    Translated to Swedish and edited with permission of the author by Thomas ON6NT.
    Date unknown. Retrieved, September 2012.

  3. Wikipedia, Kyynel (radio)
    Retrieved June 2020.
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Crypto Museum. Created: Thursday 27 September 2012. Last changed: Tuesday, 23 June 2020 - 06:40 CET.
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