Military Technology 06/2020

attack them with jamming after ascertaining the frequency in use. From a tactical and operational perspective, the dangers this posed were obvi- ous – something had to be done. That something was the advent of fre- quency-hopping radio waveforms. This approach made it impossible to hear military communications in ‘clear’ on a single channel, transmitting on an unchanged frequency, thus making the communications impossi- ble to jam. Frequency-hopping uses an ingeniously simple concept. The trans- mitting radio changes the frequency of its transmissions within a spe- cific waveband thousands of times per second in a pseudo-random se- quence – pseudo-random because the radio will actually have a specific sequence it will use to change the frequencies. This sequence will be shared with all radios using a specific frequency-hopping waveform on a specific network. The frequency-hopping scheme is shared by these radios according to a Time of Day (TOD) key, which requires each radio to have a very accurate clock, with a time signal also provided through NATO is in the midst of implementing the alliance’s new SATURN waveform, which promises a step change in communications capa- bilities for air platforms. Among the Roman gods, Saturn had his hands full, responsible as he was for wealth, liberation, agriculture, generation and renewal, among other tasks. His name was given to the second largest planet in our Solar Systems – and NATO’s Second-Generation Anti-Jam Tactical Ultra High Frequency Radio. Unsurprisingly, this rather fulsome title has been abbre- viated to SATURN; a more concise way of describing this alliance tactical communications waveform. Using a UHF waveband of 225-400MHz, the waveform was designed from the outset to be resistant to electronic at- tack (EA). SATURN picks up from where NATO’s HAVEQUICK-I/II UHF waveform left off. HAVEQUICK-I/II remains in service, but over the long term may be superseded by SATURN. To understand the benefits that SATURN will bring to NATO, it is worth reflecting briefly on history. Since the end of the Second World War, military aircraft have used the 225-400MHz waveband for air-to-air and air-to-ground/ground-to- air radio communications, exclusively for global military use, with this guarantee underwritten by the International Telecommunications Union (ITU) – the supranational United Nations organisation which acts as global custodian of the radio portion of the electromagnetic spectrum. From the earliest days, use of UHF for such communications purposes during the Second World War was primarily conducted using either voice or Morse Code transmissions. This traffic was ‘clear’ i.e. bereft of any transmis- sion security, which might help to prevent unauthorised listeners from eavesdropping on the traffic. Those using these communications could only protect the traffic with rudimentary encryption such as specific code words, the meaning of which the eavesdropper would not be privy to. The proliferation of consumer and low-priced commercial electronics from the 1960s, resulting from the mass use of the microchip, led to the proliferation of inexpensive radio scanners capable of picking up military UHF radio transmissions within range of the scanner. Not only would someone be able to hear these communications – they could potentially Thomas Withington Talk Radio: Mobile Tactical Communications Within NATO Another airborne radio accommodating the SATURN waveform is Thale’s SYNAPS-A, developed from the CONTACT transceivers the firm is building for the French armed forces. (Photo: Thales) 62 · MT 6/2020 C4I Forum Rohde and Schwarz’ M3AR series of airborne radios can carry the SATURN waveform, alongside HAVEQUICK-I/II and the firm’s proprietary SECOS waveform. (Photo: Rohde & Schwarz)