WON’T GET FOOLED AGAIN? COMMON SOURCES OF RADAR UFOS
During the 1930s British scientists discovered that when radio waves from a transmitter struck targets such as aircraft, ships and buildings they bounced back and could be detected by a receiver. The Air Ministry quickly began to develop a functioning early warning system that could be used to calculate the distance, direction and height of German aircraft by listening for the echoes returned from bursts of radio waves. Originally known as Radio Direction and Finding (RDF) the term ‘radar’ was adopted during WWII when the Chain Home system, built around the English coastline, was the key to the success of the RAF in the Battle of Britain. But despite their success, early radar systems were cluttered by noise from birds, insects, weather systems and unusual atmospheric conditions. Here are some of the most common explanations for UFOs on radar:
‘ ANGELS’
Angels were first mentioned by radar personnel at the dawn of the modern UFO era to describe invisible targets in the clear atmosphere. In March 1941 Chain Home radars detected a formation of blips moving across the English Channel. RAF fighters were sent to intercept but their crews saw nothing and the blips faded ( FT195:36-7). Similar ‘angels’ plagued the more powerful Type 80 centimetric radars that were introduced from 1954 and became a hazard for air traffic controllers. A Fighter Command investigation concluded most of these were caused by migrating seabirds and others were the result of ‘anomalous propagation’. Computers filtered out smaller echoes and increased the strength of those created by aircraft. The invention of transponders that transmit an electronic identification signal from aircraft to ground control helped to further reduce clutter on ATC radars. This means that ‘aerial phenomena’ appear on radar today only if they intrude on flightpaths and create a near miss of the type investigated by the Civil Aviation Authority’s Airprox board ( FT291:26-27).
‘ANOMALOUS PROPAGATION’
This is caused by unusual meteorological conditions that trap and bend radio waves along the surface of the Earth. AP can result in radio energy being returned from objects at distances far in excess of the radar’s normal range of operation. Sometimes moving objects such as cars, ships and low-flying aircraft have been superimposed on the usual radar picture. AP may be the ultimate source of some classic radar UFO flaps including those that plagued Washington DC during the summer of 1952 and RAF Bentwaters-Lakenheath in 1956 ( FT213:28-32). Measurements of extreme speed and height of anomalous radar targets are completely worthless if the observer is unaware that AP is present and even experienced operators have been fooled. More recently, clear air radar echoes created by backscattering from fluctuations of the index of refraction in the atmosphere have been detected by scientists using powerful radars operating at several wavelengths. One of the pioneers of radar meteorology, Dr David Atlas (1924-2015), said these experiments prove “the atmosphere will effect radar propagation in almost unbelievable ways and produce virtual targets which have apparently fantastic manoeuvrability.”
PERMANENT ECHOES
On occasion, prominent buildings have been reported as potential UFOs when ground controllers have been alerted, in real time, to mysterious visual sightings. A classic example occurred in October 1996 when the 273ft (83m) spire of Boston Stump appeared on civilian and RAF radars at the height of a UFO flap in East Anglia. The presence of the stationary echo was only flagged up as unusual when staff at RAF Neatishead in Norfolk were alerted by police and others who had spotted strange lights in the sky above The Wash ( FT223:28-29). This case even fooled defence intelligence experts. Ron Haddow listed it as the “only UK event” where three radars had simultaneously detected a UFO in UK airspace in the Condign report he produced for MoD in 2000.
INTERFERENCE
Mysterious moving echoes can appear on radars when two or more transmitters are close together. The MoD’s Flying Saucer Working Party investigated one example in 1950 when a sighting made by a RAF Meteor pilot initially appeared to have strong corroboration from a ground radar station in Sussex. Inquiries found the sighting occurred 10 minutes before the radar detection and traced the interference to a Naval radar in the English Channel. Some of the hypersonic targets detected by Belgian Air Force F-16s in March 1990 were caused by the aircraft’s own radars interfering with each other in a similar manner.
ECM: JAMMING AND SPOOFING
Electronic Counter Measures are techniques developed by military intelligence agencies to fool enemies. Early crude examples include dropping ‘chaff’ – strips of reflective foil – to jam defence radars during air raids. In 1998 the CIA revealed the existence of a formerly top-secret project, code-named Palladium, that was developed alongside the U2 spyplane in the 1950s to insert phantom aircraft into enemy radars. It was used during the Cuban crisis and later during the Vietnam war. Project leader Gene Poteat said it allowed them to “simulate an aircraft of any radar cross-section from an invisible stealth airplane to one that made a large blip on Soviet radar screens – and anything in between, at any speed and altitude, and fly it along any path.” A secret CIA-MoD experiment with Palladium might explain the radar UFO reported by USAF F-86 pilot Lt Milton Torres who was sent to investigate a blip detected by RAF radars in East Anglia one night in 1956-57 (see FT242:34-35). Torres’s airborne radar locked onto the ‘object’, which appeared to be the size of a B52 bomber, and he was ordered by the ground controller to open fire with his rockets. But 10 seconds before he received authentication the ‘bogey’ broke away and disappeared at great speed. There was no visual sighting. On return to base Torres was debriefed by a secret service agent and told his mission was Top Secret. He did not discuss it again until 1986 after retirement from the USAF.
BLACK PROJECT AIRCRAFT
According to intelligence expert Richard Aldrich, during the Cold War air defence radars in the West were frequently triggered by incursions by Black Project aircraft developed by the CIA and USAF. Incursions by ‘friendly’ Black Projects have continued with the deployment of the radar-invisible F-117A Stealth and B2 bombers in Europe from the early 1990s. The existence of the top-secret hypersonic Aurora spyplane has been denied, but declassified MoD files reveal that intelligence officers declared they “would not be surprised” if covert visits were the source of some UFO incidents reported in the UK.