A one-way voice link (OWVL) is typically a radio based communication method used by spy networks to communicate with agents in the field typically (but not exclusively) using

shortwave radio Shortwave radio is radio transmission using radio frequencies in the shortwave bands (SW). There is no official definition of the band range, but it always includes all of the High frequency, high frequency band (HF), which extends from 3 to 30& ...

frequencies. Shortwave frequencies were and are generally highly preferred for their long range, as a communications link of 1200 km is easily possible. VHF and UHF frequencies can be used for one-way voice circuits, but are generally not preferred as their range is at best 300 km (on flat terrain). Since the 1970s infrared point-to-point communication systems have been used that offer OWVLs, but the number of users was always limited. This communications system often employs recorders to transmit pre-recorded messages in real time or in

burst transmission Burst may refer to: *Burst mode (disambiguation), a mode of operation where events occur in rapid succession **Burst transmission, a term in telecommunications **Burst switching, a feature of some packet-switched networks **Bursting, a signaling mo ...

s, which minimize the time that a spy needs to be on the air. Voice-scrambling systems have been selectively used for this kind of communications circuit since the 1980s, based on operational needs. Since personal computers became cheap and readily available in the 2000s, time compressed voice scrambling for one-way and bi-directional circuits is a practically free technology. OWVLs have existed outside espionage, for example the NICAM transmission system was modified in the UK to allow for an OWVL to BBC mobile units. This OWVL was typically used for sports events, as it was highly flexible.

Historical context

During the mid- to late

Cold War The Cold War was a period of global Geopolitics, geopolitical rivalry between the United States (US) and the Soviet Union (USSR) and their respective allies, the capitalist Western Bloc and communist Eastern Bloc, which lasted from 1947 unt ...

the

STASI The Ministry for State Security (, ; abbreviated MfS), commonly known as the (, an abbreviation of ), was the Intelligence agency, state security service and secret police of East Germany from 1950 to 1990. It was one of the most repressive pol ...

(the East German intelligence agency) used point-to-point infrared technology for 2-way voice links within the divided city of Berlin. OWVLs were used intermittently. OWVL transmission methods were used during the

Falklands War The Falklands War () was a ten-week undeclared war between Argentina and the United Kingdom in 1982 over two British Overseas Territories, British dependent territories in the South Atlantic: the Falkland Islands and Falkland Islands Dependenci ...

by UK elite forces to provide information about suitable troop landing areas. This fact emerged in the late 1980s when UK veterans of the war were writing their memoirs. Argentina had access to similar technology to communicate with its military, but did not really use it during this conflict.

References

Espionage techniques {{electronics-stub

Historical context

See also

References