Airborne radio relay is a technique employing aircraft fitted with

radio relay Radio stations that cannot communicate directly due to distance, terrain or other difficulties sometimes use an intermediate radio relay station to relay the signals. A radio relay receives weak signals and retransmits them, often in a different di ...

stations for the purpose of increasing the range, flexibility, or physical

security Security is protection from, or resilience against, potential harm (or other unwanted coercive change) caused by others, by restraining the freedom of others to act. Beneficiaries (technically referents) of security may be of persons and social ...

communications Communication (from la, communicare, meaning "to share" or "to be in relation with") is usually defined as the transmission of information. The term may also refer to the message communicated through such transmissions or the field of inquir ...

systems. The aircraft may be manned or

unmanned aerial vehicle An unmanned aerial vehicle (UAV), commonly known as a drone, is an aircraft without any human pilot, crew, or passengers on board. UAVs are a component of an unmanned aircraft system (UAS), which includes adding a ground-based controller ...

Use in Vietnam

One of the first uses of airborne radio relay was by the

United States Army The United States Army (USA) is the land service branch of the United States Armed Forces. It is one of the eight U.S. uniformed services, and is designated as the Army of the United States in the U.S. Constitution.Article II, section 2, cla ...

's 1st Cavalry Division in the

Battle of Ia Drang The Battle of Ia Drang (, ; in English ) was the first major battle between the United States Army and the People's Army of Vietnam (PAVN), as part of the Pleiku Campaign conducted early in the Vietnam War, at the eastern foot of the Chu Pong Mas ...

during the

Vietnam War The Vietnam War (also known by #Names, other names) was a conflict in Vietnam, Laos, and Cambodia from 1 November 1955 to the fall of Saigon on 30 April 1975. It was the second of the Indochina Wars and was officially fought between North Vie ...

, which employed the technique to improve communications with commanders at headquarters. The action of war had shifted to the borders of

Laos Laos (, ''Lāo'' )), officially the Lao People's Democratic Republic ( Lao: ສາທາລະນະລັດ ປະຊາທິປະໄຕ ປະຊາຊົນລາວ, French: République démocratique populaire lao), is a socialist ...

and

Cambodia Cambodia (; also Kampuchea ; km, កម្ពុជា, UNGEGN: ), officially the Kingdom of Cambodia, is a country located in the southern portion of the Indochinese Peninsula in Southeast Asia, spanning an area of , bordered by Thailand t ...

, where the hilly terrain made the monetary and human cost of seizing and holding high ground, and airlifting and installing radio relay equipment prohibitive. In 1968, the

Department of the Army The United States Department of the Army (DA) is one of the three military departments within the Department of Defense of the U.S. The Department of the Army is the federal government agency within which the United States Army (U.S.) is org ...

provided four specially-equipped relay aircraft to the Division, which proved invaluable throughout the country, in particular, during the 1st Cavalry Division's relief of

Khe Sanh Khe Sanh is the district capital of Hướng Hoá District, Quảng Trị Province, Vietnam, located 63 km west of Đông Hà. During the Vietnam War, the Khe Sanh Combat Base was located to the north of the city. The Battle of Khe San ...

in 1968. The use of airborne radio relay was a great success, although two problems arose during the Vietnam War. The first was the limitations of the aircraft used as relays. The 1st Cavalry Division had originally used

C-7 Caribou The de Havilland Canada DHC-4 Caribou (designated by the United States military as the CV-2 and later C-7 Caribou) is a Canadian specialized cargo aircraft with short takeoff and landing (STOL) capability. The Caribou was first flown in 1958 ...

s as the relay aircraft, but when these planes were turned over to the

Air Force An air force – in the broadest sense – is the national military branch that primarily conducts aerial warfare. More specifically, it is the branch of a nation's armed services that is responsible for aerial warfare as distinct from an a ...

, the equipment was installed in single-engine

Otter Otters are carnivorous mammals in the subfamily Lutrinae. The 13 extant otter species are all semiaquatic, aquatic, or marine, with diets based on fish and invertebrates. Lutrinae is a branch of the Mustelidae family, which also includes wea ...

aircraft, which were too underpowered to carry the heavy equipment required for relay. Eventually, the 1st Signal Brigade was provided with six specially-equipped U-21 aircraft for use in relay operations. The second problem was that of

radio frequency interference Electromagnetic interference (EMI), also called radio-frequency interference (RFI) when in the radio frequency spectrum, is a disturbance generated by an external source that affects an electrical circuit by electromagnetic induction, electrost ...

: the limited frequency spectrum in use for combat radios meant that relay aircraft often interfered with the communication of ground units when their frequencies were overridden by the airborne units. The Army eventually assigned certain frequencies for airborne relay only, although this further limited the frequencies available to ground units.

References

{{DEFAULTSORT:Airborne Radio Relay Telecommunications techniques Aviation communications

Use in Vietnam

See also

References