Eureka beacon
Encyclopedia
The Rebecca/Eureka transponding radar was a transponder
system used as a radio homing beacon by means of a Eureka ground emitter responding to queries from an airborne Rebecca interrogator.
pulse
s per second on a frequency between 170 and 234 MHz. Upon receiving this signal the mobile, ground based Eureka rebroadcast the pulses on a different frequency. This rebroadcast signal was received by two directional 'Yagi
' array aerials on the aircraft carrying the Rebecca unit. The difference in signal amplitude between the two aerials gave the bearing of the Eureka beacon, while the delay between transmission and reception of the return pulses gave range. The system was effective only to within two miles, when the blip viewed aboard the aircraft merged with the signal transmitted by the interrogator, distorting the range, at which time the crew had to switch to visual means of locating the drop zone. Reliance on Eureka without visual confirmation invariably resulted in premature drops, as occurred during the American airborne landings in Normandy
.
A Mark X version of both Rebecca and Eureka that worked in the 1000 MHz range. This was developed for use during in-flight refueling, enabling the receiving aircraft to locate the tanker while maintaining radio silence. The Tanker aircraft carried the Eureka and the receiving aircraft carried the Rebecca. This equipment was trialled by 214 Squadron in the early 1960s.
The Rebecca code name
was derived from the phrase "recognition of beacons".
Transponder
In telecommunication, the term transponder has the following meanings:...
system used as a radio homing beacon by means of a Eureka ground emitter responding to queries from an airborne Rebecca interrogator.
Operation
The airborne Rebecca interrogator transmitted 300 3-4 μSec1 E-6 s
A microsecond is an SI unit of time equal to one millionth of a second. Its symbol is µs.A microsecond is equal to 1000 nanoseconds or 1/1000 millisecond...
pulse
Pulse
In medicine, one's pulse represents the tactile arterial palpation of the heartbeat by trained fingertips. The pulse may be palpated in any place that allows an artery to be compressed against a bone, such as at the neck , at the wrist , behind the knee , on the inside of the elbow , and near the...
s per second on a frequency between 170 and 234 MHz. Upon receiving this signal the mobile, ground based Eureka rebroadcast the pulses on a different frequency. This rebroadcast signal was received by two directional 'Yagi
Yagi antenna
A Yagi-Uda array, commonly known simply as a Yagi antenna, is a directional antenna consisting of a driven element and additional parasitic elements...
' array aerials on the aircraft carrying the Rebecca unit. The difference in signal amplitude between the two aerials gave the bearing of the Eureka beacon, while the delay between transmission and reception of the return pulses gave range. The system was effective only to within two miles, when the blip viewed aboard the aircraft merged with the signal transmitted by the interrogator, distorting the range, at which time the crew had to switch to visual means of locating the drop zone. Reliance on Eureka without visual confirmation invariably resulted in premature drops, as occurred during the American airborne landings in Normandy
American airborne landings in Normandy
The American airborne landings in Normandy were the first United States combat operations during Operation Overlord, the invasion of Normandy by the Western Allies on June 6, 1944. Around 13,100 paratroopers of the U.S. 82nd Airborne and 101st Airborne Divisions made night parachute drops early on...
.
Versions
There were large numbers of versions of the system, early models were limited to a single frequency - later ones could switch between 5 frequencies.British
Eureka Mk VII was a rack mounted, non-mobile transponder used at RAF bases for aircraft to home onto.A Mark X version of both Rebecca and Eureka that worked in the 1000 MHz range. This was developed for use during in-flight refueling, enabling the receiving aircraft to locate the tanker while maintaining radio silence. The Tanker aircraft carried the Eureka and the receiving aircraft carried the Rebecca. This equipment was trialled by 214 Squadron in the early 1960s.
American
- AN/PPN-1
- AN/PPN-1A
- AN/PPN-2
The Rebecca code name
Code name
A code name or cryptonym is a word or name used clandestinely to refer to another name or word. Code names are often used for military purposes, or in espionage...
was derived from the phrase "recognition of beacons".
See also
- AN/UPN-1AN/UPN-1The AN/UPN-1 was a radar Pathfinder marker beacon used by the Army Air Force and Airborne forces during World War II.-Use:Radar beacon AN/UPN-1, sometimes known as BUPS , is an ultra portable beacon for ground, Paratroop or shipboard use having a range of 35 to 50 miles...
- Signal Corps RadioSignal Corps RadioSignal Corps Radios were U.S. Army military communications components that comprised "sets". Under the Army Nomenclature System, SCR initially designated "Set, Complete Radio," and later "Signal Corps Radio," though interpretations have varied over time....
- List of military electronics of the United States
External links
- http://www.qsl.net/pe1ngz/airforce/airforce-raf/raf-eureka-rebecca.html
- http://www.summerof44.org.uk/Menu/Equipment/Eureka.htm
- http://histru.bournemouth.ac.uk/Oral_History/Talking_About_Technology/radar_research/rebecca_eureka.html
- http://www.duxfordradiosociety.org/equiphist/reb-eureka/reb-eureka-hist.html
- http://www.militaryradio.com/spyradio/early_mil.html picture of ground component