Allied Command Europe Highband, better known as ACE High, was a fixed service NATO radiocommunication and early warning system dating back to 1956. After extensive testing ACE High was accepted by NATO to become operational in 1964/1965.
The frequency supportability and frequency assignments were provided in accordance with the NATO Joint Civil/Military Frequency Agreement (NJFA). The system was designed to be a combined UHF troposcatter/microwave radio system, providing long-range communications in the form of telephone, telegraph and data traffic in the NATO chain of command.[1]
Its combined services produced over 200 channels and equipment was in place to multiplex them to contain up to 12 different calls each. There used to be 49 troposcatter links augmented by 40 Line Of Sight Microwave terrestrial stations, located in nine different NATO countries from northern Norway through central Europe to eastern Turkey. The transmitters broadcast at 832.56 - 959.28 MHz producing an average transmitting power of 10 kilowatts.[2]
NATO had been established in 1949 with then a supreme command (SHAPE) near Versailles, France, and the regional headquarters (RHQ) Allied Forces Northern Europe (AFNORTH) at Kolsås, Norway (responsible for Denmark, Norway and the UK), Allied Forces Central Europe (AFCENT) at Laffaux, France (responsible for Belgium, France, Germany and the Netherlands) and Allied Forces Southern Europe (AFSOUTH) at Naples, Italy (responsible for Italy, Greece and Turkey). Supreme command, the three RHQ's and all subordinated units used various communication systems to establish contact: high frequency radio networks, VHF beaming transmitters and civil or military landlines. All systems had their weakness in equipment reliability; in the maximum amount of data transferred; in encryption possibilities and in unauthorized data interception. So in the early 1950s there existed an urgent need for a reliable, foolproof long distance European communications network.
US developed tropospheric diffusion techniques, integrated in a new military communications network appeared to be the solution and in 1956 STC, a planning, design, engineering and installation company had been ordered to develop a new integrated communications network in Europe. This network consisted of a number of "backbone" stations covering the 6800km (4,200miles) distance from the north of Norway to the south of Turkey and was initially called the "Over the Horizon Troposperic scatter Communications Net" but was renamed "Allied Command Europe - Highband" (ACE-High). The network would be kept operational until the 1990s as all frequencies then had to be released to the civilian authorities.
After all components had been installed on their locations by Marconi Electronic Systems UK, (from 1968 part of General Electric Company), in 1961 the ACE-High system had officially been transferred to NATO.
In 1966 however France, under president Charles de Gaulle, withdrew from NATO integrated military structure (not from the Alliance itself) and systems had to be rerouted from France to Brunssum, Netherlands while the former Primary Control Center at Beauvais, was relocated to Lamersdorf, West-Germany.
In the early 1970s, the first geostationary satellites in the "Satellite Communication" network (SATCOM) had been activated thus expanding the ACE-High system.
The rise of the military SATCOM I-III (1971–1994), SATCOM IV (1995-now) network satellites, Internet routers, and the Central Region Integrated Communication System (CRICS) and the Crisis Response Operations in NATO Operating Systems (CRONOS) made ACE High obsolete. By the end of the 1980s, its replacement was already available but NATO postponed the ACE High phasing-out until 1995.
In 1995, the first British NATO SATCOM IV/B satellites had been activated and because the ACE-High frequencies had to be released for civil TV and mobile phone usage NATO decided to deactivate ACE-High in 1996, and the 800 MHz band frequencies became available for civilian use again.
The ACE High network included the following major sites and terminals, but also connected Line of Sight (LOS) microwave links to other networks reaching C2 centres not listed here.[3]
Pos TX RX Equipment:1 Scatter Line + 2 Radio Line
Pos 502 m TX RX Equipment:1 Radio Line
Pos 801 m TX RX Equipment:2 Scatter Line + 1 Radio Line
TX RX Equipment:1 Radio Line
Pos 627 m TX RX Equipment:2 Scatter Line
Pos 677 m AMSL TX RX Equipment:2 Scatter Line + 1 Radio Line
Pos 543 m AMSL TX RX Equipment:1 Radio Line
Pos 246 m TX RX Equipment:2 Scatter Line + 1 Radio Line
Pos TX RX Equipment:3 Radio Line
Pos TX RX Equipment:1 Radio Line
Pos 14 m TX RX Equipment:1 Radio Line
Pos 326 m TX Rx Equipment:3 Scatter Line
Pos 792 m TX RX Equipment:2 Scatter Line
Pos 135 m TX RX Equipment:2 Scatter Line + 1 Radio Line
Pos 68 m TX RX Equipment:1 Radio Line
Initially 60, 30 or 15 ft dish or billboard type antennas have been used in combination with General Electric or RCA AN/MRC80 TRC24; AN/FRC-75 or 39 radio sets. Later being replaced by newer Siemens & Halske EM 120/400 and 12/800 types. The type and beaming angle of the antennas depended of the local site position and its distance to the next relays.