resulted in premature drops, as during the American airborne landings in Normandy. Versions There were many versions of the system. Early models were limited to a single frequency; later ones could switch between five 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 was derived from the phrase "recognition of beacons". In popular culture Pathfinders - In The Company of Strangers is a 2011 movie based on Rebecca/Eureka transponding radar installed before D-Day by Airborne Pathfinders. See also Signal Corps Radio List of military electronics of the United States References Citations Bibliography T. J. Morgan - Radar - part of The Mechanical Age Library - Muller - c1950 - No ISBN. Graphic Survey of Radio and Radar Equipment Used by the Army Airforce. section 3 Radio Navigation Equipment Dated May 1945 "A Brief History of Rebecca & Eureka" , Duxford Radio Society, 16 January 2011 "Eureka / Rebecca / BABS / Lucero", from E.K. Williams, "Radar Development to 1945", P. Peregrinus Air Publications & Manuals External links 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.militaryradio.com/spyradio/beacons.html picture of ground component Radio navigation World War II espionage World War II British electronics Military equipment introduced from 1940 to 1944