50 Fun Facts About Radar

What does the acronym RADAR stand for?

The word has since become an anacronym, a plain noun with no capitals.

Which organisation coined the term RADAR in 1940?

Britain had been calling the technology RDF, for radio direction finding.

Which German physicist showed in 1886 that radio waves reflect off solid objects?

He was the first to prove the existence of the electromagnetic waves Maxwell's equations predicted.

Which German inventor patented the 'telemobiloscope' in 1904 to detect ships in fog?

It could sense a distant ship's presence but not measure its distance, and the military rejected it.

Which Russian physicist noted in 1897 that a passing ship disturbed radio signals?

He wrote that the effect might detect objects but did nothing more with it.

Which Scottish engineer led the British team that demonstrated pulsed radar in 1935?

He had earlier used radio to warn airmen of thunderstorms and claimed descent from James Watt.

What rumoured German weapon prompted the enquiry that led Britain to radar?

Arnold Wilkins showed the death ray was impossible but suggested radio detection instead.

Whose shortwave transmitter was borrowed for the Daventry Experiment of 26 February 1935?

A Handley Page Heyford bomber flew over the field while a GPO receiver watched for echoes.

What did Watson-Watt reportedly exclaim after the Daventry test succeeded?

The Treasury released £12,300 within days for further development.

What was the codename of Britain's ring of coastal early-warning radar stations?

Officially the AMES Type 1, it was the world's first early-warning radar network.

Where in Suffolk did Watson-Watt's team develop the coastal radar stations from 1936?

By 1940 the stations stretched around the whole UK coast including Northern Ireland.

Which 1940 air campaign did the coastal radar chain's early warning help the RAF to win?

It formed part of the 'Dowding system' for coordinating fighter responses.

Which two Birmingham physicists built the improved cavity magnetron in 1940?

Their first example produced hundreds of watts at a 10 cm wavelength, an unprecedented feat.

What everyday appliance later used the cavity magnetron?

A 1.1-kilowatt oven input yields about 700 watts of microwaves, around 65% efficiency.

Which 1940 British delegation carried a magnetron to the United States?

Historian James Baxter called it 'the most valuable cargo ever brought to our shores'.

Where did 'Magnetron Number 12' spend the night before its 1940 voyage to America?

The documents travelled in a lockable metal deed box strapped to a taxi roof.

Which secret US lab, organised by Alfred Loomis, developed microwave radar from 1941 to 1945?

Robert Page there refined radar with the monopulse technique in 1943.

Where on Oahu did an SCR-270 radar spot the incoming Japanese planes in 1941?

Lieutenant Kermit Tyler assumed the blip was six B-17s arriving from California.

Which American demonstrated the first elementary pulsed radar in December 1934?

He was working at the Naval Research Laboratory.

Which German firm demonstrated a pulsed radar system in May 1935?

Rudolf Kühnhold's team beat Watson-Watt's British demonstration by a month.

What did the Soviets call their first mass-produced radar, of which only 607 were built?

Development slowed after its pioneer P. K. Oshchepkov was sent to the gulag.

Which ocean liner had parts of a French obstacle-detecting radio set installed in 1935?

CSF's team under Maurice Ponte built it, though it used continuous waves rather than pulses.

What was the British codename for chaff, the strips of foil dropped to blind radar?

The Germans called it Düppel; both sides hesitated to use it in case the other copied it.

Over which city was the foil countermeasure first used, during Operation Gomorrah in 1943?

German searchlights and flak radars wandered helplessly; the results were 'spectacular'.

Chaff strips are cut to what fraction of the target radar's wavelength?

At that length the metal resonates and re-radiates the signal.

Which German radar was seized and brought to Britain in Operation Biting in 1942?

It revealed German radars used only three frequency ranges, making them easy to jam.

What phenomenon lets radar read a target's speed from a change in the returned frequency?

Doppler weather radars can track wind and rotation inside storms.

Who invented the radar speed gun, working for the Automatic Signal Company in Connecticut?

They had developed radar for the military during the Second World War.

Which nearby body was first detected by radar in 1946?

Later measurements mapped shadowed regions near its poles.

Which lab made the first unambiguous radar contact with Venus, on 10 March 1961?

The echoes gave a new, precise value for the astronomical unit.

How large was the Arecibo radar-radio dish that collapsed in 2020?

It was built into a natural sinkhole in Puerto Rico and completed in 1963.

Whose 1962 Soviet paper on edge waves shaped the design of American stealth aircraft?

The USAF translated it in 1971 and Lockheed used it in its Have Blue bid.

Which aircraft made the word 'stealth' popular in the late 1980s?

Its first large-scale public use was in the 1991 Gulf War.

What is the measure of how strongly an object scatters radio waves back called?

Corner reflectors on small boats increase it deliberately; stealth shapes minimise it.

What device of three flat surfaces meeting like a cube's inside angle returns radar to its source?

That is why stealth aircraft avoid inside corners and perpendicular surfaces.

Returned radar power falls off with what power of the range in the radar equation?

The signal must travel out and back, and spreads out both ways.

The Soviet Duga over-the-horizon radar was nicknamed what by shortwave listeners?

Its 10 Hz tapping disrupted broadcasts worldwide; one array stands near Chernobyl.

Modern high-power radar transmitters replaced magnetrons in the 1960s with which devices?

The magnetron's pulse-to-pulse changes in frequency and phase made it hard to use in phased arrays.

Where did the radar band letters such as X, S and L originate?

The IEEE and ITU later adopted the letters, and they remain in military and aviation use.

On which company's aircraft was the first commercial radar device fitted in 1938?

It was a Bell Labs unit; radar altimeters trace back to Bell telephone research.

A radar altimeter measures an aircraft's height above what?

A barometric altimeter instead gives height above a datum such as sea level.

What Oklahoma event of May 1973 did a Doppler radar document in full for the first time?

The Union City twister was tracked through its whole life cycle by the NSSL.

What colour on a weather radar image usually marks the strongest returns?

Weak returns show as blue or green.

Ground-penetrating radar uses which part of the radio spectrum?

It can image pipes, cables, rock, ice and even archaeological remains beneath the surface.

Which weather phenomena are usually transparent to radio waves?

Some frequencies absorbed by water vapour or oxygen are avoided unless detecting them is the goal.

Which laser-based cousin of radar is often used by self-driving cars?

It uses mostly infrared light rather than radio waves.

Which US Navy pair found in 1922 that ships crossing a Potomac radio beam made the signal fade?

The Navy did not follow up until Lawrence Hyland saw aircraft do the same in 1930.

How much did the UK government award Watson-Watt for radar, ten years after his knighthood?

He later moved to Canada and the US and appeared as a mystery guest on To Tell the Truth.

In which two harbours did Christian Hülsmeyer demonstrate his 1904 ship-detecting device to German military officials?

His spark-gap system worked on a 50 cm wavelength and already used a horn antenna with a parabolic reflector, but the military rejected it.

Which wartime navigation system, complementary to radar, was used by the RAF's Pathfinder force?

The war also drove demand for small, light sets to fit night fighters and maritime patrol aircraft.