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The Reeves AN/MSQ-77 Bomb Directing Central, Radar (nickname "Miscue 77") was a
United States Air Force The United States Air Force (USAF) is the Air force, air service branch of the United States Department of Defense. It is one of the six United States Armed Forces and one of the eight uniformed services of the United States. Tracing its ori ...
automatic tracking radar/computer system for
command guidance Command guidance is a type of missile guidance in which a ground station or aircraft relay signals to a guided missile via radio control or through a wire connecting the missile to the launcher and tell the missile where to steer to intercept its ...
of aircraft. It was often used during
Vietnam War The Vietnam War (1 November 1955 – 30 April 1975) was an armed conflict in Vietnam, Laos, and Cambodia fought between North Vietnam (Democratic Republic of Vietnam) and South Vietnam (Republic of Vietnam) and their allies. North Vietnam w ...
bomb runs at nighttime and during bad weather. Developed from the Reeves AN/MSQ-35, the AN/MSQ-77 reversed the process of
Radar Bomb Scoring Radar Bomb Scoring is a combat aviation ground support operation used to evaluate Cold War aircrews' effectiveness with simulated unguided bomb drops near radar stations of the United States Navy, the USAF Strategic Air Command, and Army Projec ...
by continually estimating the bomb impact point before bomb release with a vacuum tube ballistic computer. Unlike "Course Directing Central" systems which guided aircraft to a predetermined release point, the AN/MSQ-77 algorithm continuously predicted bomb ''impact'' points during the radar track while the AN/MSQ-77's control commands adjusted the aircraft course. A
close air support Close air support (CAS) is defined as aerial warfare actions—often air-to-ground actions such as strafes or airstrikes—by military aircraft against hostile targets in close proximity to friendly forces. A form of fire support, CAS requires ...
regulation prohibited AN/MSQ-77 Combat Skyspot bombing within of friendly forces unless authorized by a
Forward Air Controller Forward air control is the provision of guidance to close air support (CAS) aircraft intended to ensure that their attack hits the intended target and does not injure friendly troops. This task is carried out by a forward air controller (FAC). ...
, and "on several occasions" strikes were as close as . Post-war the MSQ-77 was used on US and other training ranges for
Radar Bomb Scoring Radar Bomb Scoring is a combat aviation ground support operation used to evaluate Cold War aircrews' effectiveness with simulated unguided bomb drops near radar stations of the United States Navy, the USAF Strategic Air Command, and Army Projec ...
(RBS). The AN/MSQ-77 was also periodically used for post-Vietnam ''commanding'' of bombers during simulated ground directed bombing to maintain aircrew and radar crew GDB proficiency (RBS could be used to score the simulated GDB mission). Most AN/MSQ-77s were replaced by solid-state equipment near the end of the
Cold War The Cold War was a period of global Geopolitics, geopolitical rivalry between the United States (US) and the Soviet Union (USSR) and their respective allies, the capitalist Western Bloc and communist Eastern Bloc, which lasted from 1947 unt ...
.


History

Ground radar systems for automated guidance of aircraft to a predetermined point (e.g., for bomb release using a
bombsight A bombsight is a device used by military aircraft to drop bombs accurately. Bombsights, a feature of combat aircraft since World War I, were first found on purpose-designed bomber aircraft and then moved to fighter-bombers and modern tactica ...
or avionics radar) included the July 1951 AN/MPQ-14 Radar Course Directing Central. By 1954, the MARC (
Matador A bullfighter or matador () is a performer in the activity of bullfighting. ''Torero'' () or ''toureiro'' (), both from Latin ''taurarius'', are the Spanish and Portuguese words for bullfighter, and describe all the performers in the activ ...
Airborne Radio Control) used the AN/MSQ-1A for missile guidance to the terminal dive point, and
SAGE #REDIRECT Sage {{redirect category shell, {{R from other capitalisation{{R from ambiguous page ...
GCI provided computer-controlled guidance of aircraft to continuously computed interception points (1958
AN/FSQ-7 The AN/FSQ-7 Combat Direction Central, referred to as the Q7 for short, was a computerized air defense command and control system. It was used by the United States Air Force for ground-controlled interception as part of the Semi-Automatic Grou ...
Bomarc missile The Boeing CIM-10 Bomarc ("Boeing Michigan Aeronautical Research Center") (IM-99 Weapon System prior to September 1962) was a supersonic ramjet powered long-range surface-to-air missile (SAM) used during the Cold War for the air defense of Nor ...
guidance and the later Ground to Air Data Link Subsystem for fighters). Despite the availability of solid-state military guidance computers in 1961, planning for a USAF vacuum-tube trajectory computer/radar system began in early 1965. In October 1965, F-100s tested the AN/MSQ-77 at Matagorda Island General Bombing and Gunnery Range on the
Texas Gulf Coast Texas Gulf Coast is an intertidal zone which borders the Coast, coastal region of South Texas, Southeast Texas, and the Texas Coastal Bend. The Texas coastal geography boundaries the Gulf of Mexico encompassing a geographical distance relative be ...
. In March 1966, AN/MSQ-77 operations using the "reverse MSQ method" began and continued through August 197

for guiding B-52s and tactical fighters and bombers ("chiefly flown by North American F-100 Super Sabre, F-100's"). By March 1967, 15,000 Skyspot sorties had been flown, and raids controlled by AN/MSQ-77s included those of
Operation Menu Operation Menu was a covert United States Strategic Air Command (SAC) tactical bombing campaign conducted in eastern Cambodia from 18 March 1969 to 26 May 1970 as part of the Vietnam War. The targets of these attacks were sanctuaries and base ar ...
from
Bien Hoa Air Base Bien Hoa Air Base (Vietnamese language, Vietnamese: ''Sân bay Biên Hòa'') is a Vietnam People's Air Force (VPAF) military airfield located in South-Central southern Vietnam about from Ho Chi Minh City, across the Dong Nai river in the norther ...
, Operation Niagara, and
Operation Arc Light During Operation Arc Light (sometimes Arclight) from 1965 to 1973, the United States Air Force deployed B-52 Stratofortresses from bases in the U.S. Territory of Guam to provide battlefield air interdiction during the Vietnam War. This included ...
. Additional AN/MSQ-77 missions included those with MC-130 Commando Vault aircraft to clear landing zones and at least 1 helicopter evacuation of wounded on August 13, 1966.
partial transcription at 1stCombatEvaluationGroup.com)
;Commando Club: To allow
command guidance Command guidance is a type of missile guidance in which a ground station or aircraft relay signals to a guided missile via radio control or through a wire connecting the missile to the launcher and tell the missile where to steer to intercept its ...
bombing of
Hanoi Hanoi ( ; ; ) is the Capital city, capital and List of cities in Vietnam, second-most populous city of Vietnam. The name "Hanoi" translates to "inside the river" (Hanoi is bordered by the Red River (Asia), Red and Black River (Asia), Black Riv ...
and
Haiphong Haiphong or Hai Phong (, ) is the third-largest city in Vietnam and is the principal port city of the Red River Delta. The municipality has an area of , consisting of 8 urban districts, 6 rural districts and 1 municipal city (sub-city). Two o ...
targets out of range of the initial Skyspot AN/MSQ-77 sites, the "'' 1st CEVG began " Combat Keel" tests using F-4s guided by an MSQ-77 on the '' USS Thomas J. Gary" in the
Gulf of Tonkin The Gulf of Tonkin is a gulf at the northwestern portion of the South China Sea, located off the coasts of Tonkin ( northern Vietnam) and South China. It has a total surface area of . It is defined in the west and northwest by the northern co ...
during late 1967 after the March 1967 "Combat Target" task force recommended a closer site. By 1 November 1967, the USAF Heavy Green operation had prepared a Laos mountaintop site and installed an MSQ-77 variant in rugged shelters without trailer frames, wheels, etc. for helicopter transport. Although the central's range was limited by the UHF radio reliability for A/C commands during the bomb run, " Commando Club" used a relay aircraft to retransmit communications between
Lima Site 85 Lima Site 85 (LS-85 alphanumeric code of the phonetic 1st letter used to conceal this covert operation) was a clandestine military installation in the Royal Kingdom of Laos guarded by the Hmong "Secret Army", the Central Intelligence Agency, a ...
and the bomber. LS-85's operations ended with the 1968
Battle of Lima Site 85 The Battle of Lima Site 85, also called Battle of Phou Pha Thi, was fought as part of a military campaign waged during the Vietnam War and Laotian Civil War by the North Vietnamese People's Army of Vietnam (PAVN) and the Pathet Lao, against airm ...
defeat by
sapper A sapper, also called a combat engineer, is a combatant or soldier who performs a variety of military engineering duties, such as breaching fortifications, demolitions, bridge-building, laying or clearing minefields, preparing field defenses ...
s after
North Vietnam North Vietnam, officially the Democratic Republic of Vietnam (DRV; ; VNDCCH), was a country in Southeast Asia from 1945 to 1976, with sovereignty fully recognized in 1954 Geneva Conference, 1954. A member of the communist Eastern Bloc, it o ...
had correlated bombings were occurring during LS-85 transmissions (the site's central and other buildings were destroyed by a later U.S. air raid.) Additional casualties of AN/MSQ-77 personnel included 1 killed in an enemy rocket attac

and 6 Skyspot personnel killed in a 1966 ambush on a survey mission. Following -77 modifications in 1968, subsequent changes included a solid-state digital printer for RBS ("Digital Data System") and implementation of a Air Force Suggestion Program, USAF suggestion for RBS to use a late-1970s
programmable calculator Programmable calculators are calculators that can automatically carry out a sequence of operations under the control of a stored computer programming, program. Most are Turing complete, and, as such, are theoretically general-purpose computers. ...
to supersede the Bomb Trajectory Group, eliminating alignment procedures for its amplifiers. In 1989, remains of an F-4C Weapon System Officer shot down during a November 10, 1967, AN/MSQ-77 bomb run were recovered in Southeast Asia. Developed from the AN/MSQ-77 and also used in Vietnam was the monopulse India-band Reeves AN/TSQ-96 Bomb Directing Central

with a solid state Univac 1219B ballistic computer (Mark 152 fire control computer

and the AN/MSQ-77/96 systems for GDB were replaced by the US Dynamics AN/TPQ-43 Radar Bomb Scoring Set ("Seek Score"). There were 5 MSQ-77s at
Nellis Air Force Base Nellis Air Force Base ("Nellis" colloquialism, colloq.) is a United States Air Force military installation, installation in southern Nevada. Nellis hosts Aerial warfare, air combat exercises such as Exercise Red Flag and close air support exerc ...
in 199

and the "MSQ-77 or equivalent" was still listed in 2005 as support equipment for airdrops from Ground Radar Aerial Delivery System (GRADS) aircraf

The AN/MSQ-77 antenna at the " Combat Skyspot Memorial" on
Andersen Air Force Base Andersen Air Force Base (Andersen AFB, AAFB) is a United States Air Force base located primarily within the village of Yigo in the United States territory of Guam. The host unit at Andersen AFB is the 36th Wing (36 WG), assigned to the Pacif ...
was destroyed by a typhoon


Locations

Initial AN/MSQ-77 sites were the production plant Reeves Instrument Corporation, Reeves-Ely had built in 1958 at
Roosevelt Field Roosevelt Field is a former airport, located in the East Garden City section of Uniondale, on Long Island, New York, United States. Originally called the Hempstead Plains Aerodrome, or sometimes Hempstead Plains field or the Garden City Aero ...
o
East Gate Blvd
in
Garden City, New York Garden City is a village located in Nassau County, on Long Island, in New York, United States. The population was 23,272 at the time of the 2020 census. The Incorporated Village of Garden City is primarily located within the Town of Hempstead ...
; and the
Matagorda Island Matagorda Island (), ''Spanish for'' "thick bush," is a 38-mile (61 km) long barrier island on the Texas Gulf coast, located approximately south of Port O'Connor, Texas, Port O'Connor, in the southernmost part of Calhoun County, Texas, Ca ...
test site also used for "Busy Skyspot" training of Vietnam crew

(moved to Bergstrom AFB in 1970). Deployment sites were the Vietnam War operating locations, the wartime site at the Nellis Range, and post-war CONUS RBS and overseas sites (e.g., Korea). The last AN/MSQ-77 locations (e.g., at museums after retirement

included the
Ellsworth Air Force Base Ellsworth Air Force Base (AFB) is a United States Air Force (USAF) base located about northeast of Rapid City, South Dakota, just north of the town of Box Elder. The host unit at Ellsworth is the 28th Bomb Wing (28 BW). Assigned to the Glob ...
Museum (near the Antelope Butte, Belle Fourche, Conner, & Horman RBS sites) and: *Serial Number 1: ... * Serial Number ? Detachment 7, !CEVG Ashland, Maine *Serial number 7: Detachment 12, 1CEVG Hawthorne, Nevada from June 1982 until site decommissioning in August 1986 and relocation to Detachment 17, 1CEVG Havre, Montana. Upon decommissioning of Havre, MT Serial Number 7 went to Detachment 18, Forsyth, Montana for SAC Bomb-Comp 1987 and then to Detachment 20, 1CEVG Conrad, Montana in early 1988. Was later modified by replacing the Cassegrain antenna with a Fresnel lens antenna, as was used on the MSQ-46. After the antenna (and associated equipment) modification, S/N 7 was used by the HQ 1CEVG "Bug" team to validate new site locations. *Serial number 10: Eighth Air Force Museum (
Barksdale AFB Barksdale Air Force Base (Barksdale AFB) is a United States Air Force (USAF) base in Bossier Parish, Louisiana, in northwest Louisiana. Much of the base is within the city limits of Bossier City, Louisiana, along the base's western and northwest ...
) after use at Hawthorne Bomb Plot (), Guam, and Phu Bai Air Base, Vietnam War OL 24

Served as "Secondary" radar at Mobile Duty Location (MDL) 35 Climax, KS from Jan - Jun 1982 *Serial Number 11: ... *Serial Number 12:
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after use at Nakhon Phanom RTAFB (NKP) Vietnam War OL-27 (BROMO

and initial testing at Bryan Air Force Base, Bryan Field, Texas (1st AN/TSQ-81: variant of AN/MSQ-77) *Serial Number 13: destroyed Lima Site 85 variant previously used at Vietnam War OL-23 and tested at Bryan Field *Serial Number 21: Used as "Primary" radar at Mobile Duty Location (MDL) 35 Climax, KS from Jan - Jun 1982. MSQ-77 S/N 10 served as "Secondary" for the ORI/BUY NONE missions at MDL 35 during that timeframe.


Equipment and functions

In addition to the communication and maintenance van, other AN/MSQ-77 trailers were the radar van with roof-mounted
Cassegrain antenna In telecommunications and radar, a Cassegrain antenna is a parabolic antenna in which the Antenna feed, feed antenna is mounted at or behind the surface of the concave main parabolic reflector dish and is aimed at a smaller Convex mirror, convex ...
, "control and plotting van, two diesel generator vans, ndan administrative and supply van" which were emplaced as a military installation at the surveyed site. The primary modification for the AN/MSQ-77 was the control equipment for aircraft guidance (ballistic computer, guidance/release circuitry, and UHF command equipment). The central also had an added beacon tracking capability used when the aircraft had a receiver/transmitter (e.g., Motorola SST-181 X Band Beacon Transponderbr>
to increase the range, so the radar site could be located farther from the hostile region of bombing targets. Beacon track upgrades included radar circuitry to switch the heterodyne receiver to demodulate the transponder frequency, compensation for the transponder delay, and modification of the central's plotting board circuitry to allow display for increased ranges. The plots were of tracks calculated by the computer's Aircraft Coordinates and Plotting Group which converted radar spherical coordinates, spherical data to plotting board cartesian coordinates ( non-inertial ''east, north, up'' coordinate system) using sine/cosine voltages and radar-estimated range respectively from the Antenna Group (azimuth/elevation resolvers) and from the Track Range Computer. Additional A/C Coordinates amplifiers computed the velocity components (not plotted) which along with the track position components were provided as initial bomb conditions to the ballistic computer (Bomb Trajectory Group).


Bomb Trajectory Group

The Bomb Trajectory Group (BTG) was the AN/MSQ-77's analog ballistic computer using 3-dimensional double-integration to continually predict the bomb impact point from an aircraft track during a bomb run. The Cartesian aircraft data were propagated by the BTG mathematical modeling which included aerodynamics for different bombs, Earth "curvature and
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corrections", and
vacuum tube A vacuum tube, electron tube, thermionic valve (British usage), or tube (North America) is a device that controls electric current flow in a high vacuum between electrodes to which an electric voltage, potential difference has been applied. It ...
integrating amplifiers. The integration was based on the varying aircraft position and velocity prior to the bomb release, so as with the use of the
Norden bombsight The Norden Mk. XV, known as the Norden M series in U.S. Army service, is a bombsight that was used by the United States Army Air Forces (USAAF) and the United States Navy during World War II, and the United States Air Force in the Korean War, ...
analog computer in
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, a nearly steady bomb run was required for the AN/MSQ-77 to provide sufficient bombing accuracy. As in the 1950s Nike missile guidance system(s), electro-mechanical servos controlled sine/cosine resolvers in a feedback loop for computing the simulated bomb's horizontal velocity and along with the drop rate, the simulated bomb's airspeed and dive angle ("Pitch Servo"). Likewise, a "Z servo" allowed the Air Resistance Circuits to adjust for altitude-varying air density, and the drag aerodynamics were vectorized by a servo operating potentiometers to pick-off 3 bomb-specific deceleration voltages based on each cartesian velocity voltage.


Ground directed bombing

The AN/MSQ-77 radar track began after the aircraft (A/C) arrived near the Initial Point (IP) on a heading toward the target. When the computer's groundspeed and elevation rate servos had stabilized to the A/C cartesian velocity from the differentiating amplifiers, an operator placed the central into "computer track" to provide rate-aided tracking signals to the radar. With the computer track and the central having target position, A/C heading, & bomb type information; and with the Bomb Trajectory Group's servos tracking the bomb-in-aircraft course and pitch, the operator then activated the BTG integrators for the
computer simulation Computer simulation is the running of a mathematical model on a computer, the model being designed to represent the behaviour of, or the outcome of, a real-world or physical system. The reliability of some mathematical models can be determin ...
to begin integrating a bomb trajectory from the A/C coordinates at that integration start point. Acceleration voltages from the BTG dynamic models were double-integrated by the 6 computer amplifiers which generated 3 voltages for the simulated bomb displacement (altitude, north, & east deltas) which were summed to the A/C position (simulated bomb release point, BRP). Use of the continually-changing current A/C position as the simulated BRP ensured a more accurate Earth Curvature Correction (ECC) was generated for the simulated bomb's horizontal range from the radar. When the simulated bomb's altitude (simulated BRP altitude - integrated altitude delta + altitude ECC) equalled the target height, the integration automatically stopped, and the integrated ''displacements'' were held as constant altitude, north, and east ''delta'' voltages. Subsequent summing of more current simulated bomb release points (A/C bomb run positions after the integration ended) with the integrator deltas generated a path of simulated bomb impact (SBI) points that moved relative to the A/C position throughout the remainder of the bomb run. The latest SBI was the AN/MSQ-77's best estimate of the impact position if bomb release was from the current A/C position: The AN/MSQ-77 control algorithm continually commanded the A/C so the BTG simulated bomb impact point, which was plotted separately from the A/C track, would move toward the target. While the A/C was being guided, an AN/MSQ-77 bomb release algorithm used a model for the ''future'' path of simulated bomb impact points to predict the nearest impact to the target (a No-Go condition aborted before effecting an outlying bomb release). Instead of releasing from the A/C position corresponding to the nearest predicted impact point, the AN/MSQ-77 began the bomb release sequence just prior, which accounted for the delay in generating the radio command, in transmitting the command, and in the A/C effecting the mechanical release. The delay time was based on calibration testing of the AN/MSQ-77 with A/C bomb release circuitry (e.g., mean bomb release time for salvo drops from B-52s).


Accuracy

Although the 1967 Commando Club missions against
North Vietnam North Vietnam, officially the Democratic Republic of Vietnam (DRV; ; VNDCCH), was a country in Southeast Asia from 1945 to 1976, with sovereignty fully recognized in 1954 Geneva Conference, 1954. A member of the communist Eastern Bloc, it o ...
by the
7th Air Force The Seventh Air Force (Air Forces Korea) (7 AF) is a Numbered Air Force of the United States Pacific Air Forces (PACAF). It is headquartered at Osan Air Base, South Korea. The command's mission is to plan and direct air component operations in ...
were temporarily suspended due to successful enemy defenses on November 18, the AN/MSQ-77 variant at LS-85 had effected a direct hit (zero miss distance) as well as a miss—its Commando Club CEP through November 16 for "14 runs was 867 feet". The suspension period for modifying attack tactics was used to reduce GDB errors of LS-85, since other Skyspot sites had been more accurate. AN/MSQ-77 errors included the typical automatic tracking radar errors such as the antenna lag due to the conical scan tracking, Track Range Computer error, any inaccuracy of the A/C transponder delay value used by the central, and the range offset of the A/C transponder antenna from the actual position of the bomb release point(s) on the A/C (particularly negligible when the radar was tracking from the side of the A/C). The AN/MSQ-77 compensation for antenna lag during rate-aided computer track used a telescopic
CCTV Closed-circuit television (CCTV), also known as video surveillance, is the use of closed-circuit television cameras to transmit a signal to a specific place on a limited set of monitors. It differs from broadcast television in that the signa ...
system with operator's joystic

to aim the antenna axis toward the A/C (e.g., bomb bay section of the fuselage). Additional Talk:Reeves AN/MSQ-77 Bomb Directing Central, AN/MSQ-77 errors were in the bomb trajectory algorithm (e.g., different simulation rates for each of 6 integrating amplifiers) and in the bomb release algorithm.


See also

*
List of radars A radar is an electronic system used to determine and detect the range of target and maps various types of targets. This is a list of radars. Argentina Australia Brazil Egypt Europe India Military Airborne *LCA MMR - 3D advanced, li ...
*
List of military electronics of the United States This article lists American military electronic instruments/systems along with brief descriptions. This list specifically identifies electronic devices which are assigned designations according to the Joint Electronics Type Designation System ...
*


References

{{Reflist , refs= {{Cite manual , chapter=Bomb Trajectory Group , title=AN/MSQ-77 Technical Order , publisher=
United States Air Force The United States Air Force (USAF) is the Air force, air service branch of the United States Department of Defense. It is one of the six United States Armed Forces and one of the eight uniformed services of the United States. Tracing its ori ...
(include
Figure 1-1 Bomb Trajectory Group functional block diagram)
/ref> {{Cite book , last=Lake , first=Jon , year=2004 , title=B-52 Stratofortress Units in Combat 1955-73 , url=https://books.google.com/books?id=U0zIt5KPEbQC&pg=PA23 , via=
Google Books Google Books (previously known as Google Book Search, Google Print, and by its code-name Project Ocean) is a service from Google that searches the full text of books and magazines that Google has scanned, converted to text using optical charac ...
, publisher=
Osprey Publishing Osprey Publishing is a British publishing company specializing in military history formerly based in Oxford. Predominantly an illustrated publisher, many of their books contain full-colour artwork plates, maps and photographs, and the company p ...
, page=23 , access-date=2012-06-22, isbn=9781841766072
{{Cite report , last=Rowley , first=Lt. Col Ralph A. , date=February 1976 , title=Tactics and Techniques of Close Air Support Operations 1961-1973 , url=http://www.afhso.af.mil/shared/media/document/AFD-110323-037.pdf , archive-url=https://web.archive.org/web/20111127112859/http://www.afhso.af.mil/shared/media/document/AFD-110323-037.pdf , url-status=dead , archive-date=November 27, 2011 , work=The Air Force in Southeast Asia , publisher=Office of Air Force History , page=92 , access-date=2012-07-04 , quote=''In March 1966 the first MSQ-77 arrived at Bien Hoa. … Skyspot's accuracy let heavy bombs be dropped on occasion within 250 meters of friendly positions. …many maps of South Vietnam contained distance errors of up to 300 meters. … Skyspot (S) MSQ-77 and TPQ-10 ground radars'' {{Cite book , last=Schlight , first=John , date= , title=The War in South Vietnam: The Years of the Offensive (1965-1968) , url=http://www.afhso.af.mil/shared/media/document/AFD-101013-038.pdf , series=The United States Air Force in Southeast Asia , access-date=2012-06-16{{dead link, date=March 2025, bot=medic{{cbignore, bot=medic NOTE: Lake 2004, p. 48, mistakenly says the "normal limit (with two ''Skyspot'' beacons) was 3300 yards from friendly forces", but
TACAN A tactical air navigation system, commonly referred to by the acronym TACAN, is a navigation system initially designed for naval aircraft to acquire moving landing platforms (i.e., ships) and later expanded for use by other military aircraft. It p ...
used multiple beacons, not Skyspot--which used only one radar even if a non-transmitting Skyspot backup receiving the A/C transponder returns later tracked/commanded the bomb run.
{{Cite report , last=Schlight , first=John , year=2003 , publisher=Air Force History and Museums Program , title=Help From Above: Air Force Close Air Support of the Army1946-1973 , url=http://www.docstoc.com/docs/7216503/AF-Close-Support-for-the-Army-1946-1973 , format=DocStoc.com image , page=330 , access-date=2012-06-25 (als
available from Scribd
{{Cite report , last=Wolk , first=Herman S , date=June 1969 , title=R&D for Southeast Asia, 1965-1967 , url=http://www.afhso.af.mil/shared/media/document/AFD-110322-017.pdf , work=USAF Plans and Policies , publisher=Office of Air Force History , access-date=2012-05-21 , quote= On 1 November 1967, another MSQ-77 became operational in Laos, but it was destroyed by the enemy in March 1968. DJSM-800-68 (TS ), Memo for DDR&E, CSAF, CNO, et al, 28 June 68, subj: Update of the NIGHT SONG Study , archive-date=2012-04-23 , archive-url=https://web.archive.org/web/20120423101321/http://www.afhso.af.mil/shared/media/document/AFD-110322-017.pdf , url-status=dead {{Cite report , last=Wolk , first=Herman S , date=July 1970 , title=R&D for Southeast Asia: 1968 , url=http://www.afhso.af.mil/shared/media/document/AFD-110322-015.pdf , work=USAF Plans and Policies , publisher=Office of Air Force History , access-date=2012-07-14{{dead link, date=March 2025, bot=medic{{cbignore, bot=medic {{Citation , last=Wheeler , first=Gen. Earl G , author-link=Earle Wheeler , date=25 Apr 1967 , title=Installation of MSQ-77 in Northern Laos , url=http://www.dod.mil/pubs/foi/International_security_affairs/vietnam_and_southeast_asiaDocuments/668.pdf , format= CJCS memorandum , access-date=2012-05-21 , url-status=dead , archive-url=https://web.archive.org/web/20120916045829/http://www.dod.mil/pubs/foi/International_security_affairs/vietnam_and_southeast_asiaDocuments/668.pdf , archive-date=2012-09-16 Computer systems of the United States Air Force Radars of the United States Air Force 1965 establishments in the United States 1965 in military history Computer-related introductions in 1965 1990 in military history Analog computers Aviation ground support equipment Ballistics Ground radars Military equipment of the Vietnam War Military equipment introduced in the 1960s Military electronics of the United States Aerial warfare ground equipment