The Defence High Frequency Communications Service (DHFCS) is an HF communication system provided to the UK Ministry of Defence by a private contractor, Babcock International. Its primary users are the Royal Navy and the Royal Air Force.

The DHFCS consists of six pairs of transmitter and receiver sites, all of which are remotely controlled by the Network Control Station at Forest Moor (ALE address: XSS) and the Alternate Network Control Station at Kinloss (ALE address: XSA).

Region Station Type
UK (North) Crimond Transmitter
Kinloss Receiver
UK (Middle) Inskip Transmitter
Forest Moor Receiver
UK (South) St. Eval Transmitter
Penhale Sands Receiver
Cyprus Salt Lake Transmitter
Episkopi Receiver
Ascension Island Donkey Plain Transmitter
Airhead Receiver
Falkland Islands Bush Rincon Transmitter
Mocho Pond Receiver

The DHFCS allocates transmitters and receivers at the above locations to its users, and operates the infrastructure required to get their messages on the air. The ALE address XSS is used by the Network Control Station regardless of the user, the service, and the location.