page_title: Tropospheric scatter
section_title: Tactical Troposcatter Communication systems
hierarchical_section_title: Tropospheric scatter / Tactical Troposcatter Communication systems
caption_attribution_description: English: A close-up view of dual 9 1/2' Tropo scatter microwave dishes. They are the quick reaction antenna for the TRC-170 Tropo Scatter Microwave System that sends data to the Air Operations Center and Joint Forces Air Command. Location: FORT BLISS, TEXAS (TX), UNITED STATES OF AMERICA (USA)
context_page_description: Tropospheric scatter is a method of communicating with microwave radio signals over considerable distances – often up to 300 kilometres, and further depending on terrain and climate factors. This method of propagation uses the tropospheric scatter phenomenon, where radio waves at UHF and SHF frequencies are randomly scattered as they pass through the upper layers of the troposphere. Radio signals are transmitted in a narrow beam aimed just above the horizon in the direction of the receiver station. As the signals pass through the troposphere, some of the energy is scattered back toward the Earth, allowing the receiver station to pick up the signal.
  Normally, signals in the microwave frequency range travel in straight lines, and so are limited to line of sight applications, in which the receiver can be 'seen' by the transmitter. Communication distances are limited by the visual horizon to around 30–40 miles. Troposcatter allows microwave communication beyond the horizon. It was developed in the 1950s and used for military communications until communications satellites largely replaced it in the 1970s.
context_section_description: As well as the permanent networks detailed above, there have been many tactical transportable systems produced by several countries:-
  Soviet / Russian Troposcatter Systems
  MNIRTI R-423-1 Brig-1/R-423-2A Brig-2A/R-423-1KF
  MNIRTI R-444 Eshelon / R-444-7,5 Eshelon D
  MNIRTI R-420 Atlet-D
  NIRTI R-417 Baget/R-417S Baget S
  NPP Radiosvyaz R-412 A/B/F/S TORF
  MNIRTI R-410/R-410-5,5/R-410-7,5 Atlet / Albatros
  MNIRTI R-408/R-408M Baklan
  People's Republic of China (PRoC), People's Liberation Army (PLA) Troposcatter Systems
  CETC TS-504 Troposcatter Communication System
  CETC TS-510/GS-510 Troposcatter Communication System
  Western Troposcatter Systems
  AN/TRC-97 Troposcatter Communication System
  AN/TRC-170 Tropospheric Scatter Microwave Radio Terminal
  AN/GRC-201 Troposcatter Communication System
  The U.S. Army and Air Force use tactical tropospheric scatter systems developed by Raytheon for long haul communications.  The systems come in two configurations, the original "heavy tropo", and a newer "light tropo" configuration exist.  The systems provide four multiplexed group channels and trunk encryption, and 16 or 32 local analog phone extensions. The U.S. Marine Corps also uses the same device, albeit an older version.
caption: US Army TRC-170 Tropo Scatter Microwave System
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