With reference to an aircraft flying too low to be detected by a radar, the phrases under the radar, off the radar and below the radar are used of something or someone that cannot be detected.
The phrase under the radar occurs, for example, in the review of Squid Game: The Challenge (i.e., the real-life television version of the Netflix drama)—review by Rebecca Nicholson, published in The Guardian (London and Manchester, England) of Monday 20th November 2023:
Squid Game the drama is, of course, a satire: a critique of capitalism that could undermine the notion of real people ruthlessly competing to win loads of cash. In this respect, it is a little sneaky, though read this as you wish: either it’s making a point under the radar, or it’s having its cake and eating it.
The earliest figurative uses that I have found of the phrases under the radar, off the radar and below the radar are as follows, in chronological order; I have included uses of those phrases in comparisons:
1-: From the column Mirror of Your Mind, by John Conwell, published in the San Francisco Examiner (San Francisco, California, USA) of Sunday 10th August 1969:
The modern girl is keeping a weather eye out for her romantic hero, but he must fit into her life and she in his without knocking all ideals and principles out of whack. She wants to be swept off her feet, but not off the radar beam that keeps her on course during her headlong flight into romance.
2[?]-: From Bass Run Off San Quentin, by Bud Boyd, published in the San Francisco Chronicle (San Francisco, California, USA) of Friday 21st November 1969—I am unsure whether “the radar screen” is figurative or not:
A good run of striped bass is underway off the San Quentin Flats, according to Jerry Vest, admiral of the fleet of fishing boats that bear his name out of Fisherman’s Whart [sic].
[…]
On the opposite side of San Pablo Bay, bullheads seem to be the best method for catching stripers, although the results have been spotty so far this week. A few of the more knowledgeable experts have been scoring off the radar screen and between the pumphouse and Mare Island rockwall, with catches to 30 pounds, including a few limits, reported recently.
3-: From Beating Arkansas Doesn’t A Season Make, by Kyle Griffin, sports editor, published in The Commercial Appeal (Memphis, Tennessee, USA) of Saturday 30th October 1971—Claude Gibson (born 1939) was the coach of the Tulsa Golden Hurricane football team:
Gibson’s Hurricane takes on Tennessee’s disturbing Volunteers at 1 p.m. (Memphis time) here Saturday […].
[…] There is a chance that Tulsa will make it an interesting afternoon. This is the Hurricane which snuck under the radar screen and in 15 minutes completely devastated a proud and forceful Arkansas team.
4-: From Lassiter, Jones Too Much For Vikings; Spartans Soar, the account of a baseball match between Elizabeth City (the Vikings) and Norfolk State (the Spartans), by Bob Lipper, Virginian-Pilot sports writer, published in The Virginian-Pilot (Norfolk, Virginia, USA) of Saturday 22nd January 1972—ICBM stands for intercontinental ballistic missile:
Moore, whose shooting range rivals an ICBM, gave the fans a couple of parting shots, through a 20-footer and another jumper launched from off the radar screen; but they merely cut a seven-point margin to the final three.
5-: From Big flop could kill off Muskie, about the Democratic Party presidential primary in Pennsylvania, by Bruce Biossat, published in the Wichita Falls Record News (Wichita Falls, Texas, USA) of Tuesday 25th April 1972:
On his own, Humphrey should not make it big here. I he does, credit a Muskie downfall that might take him right off the radar screen.
6-: From Operation ‘Do Not Disturb’, by the U.S. journalist David S. Broder (1929-2011), published in The Washington Post (Washington, District of Columbia, USA) of Wednesday 9th January 1974:
Every time the Nixon administration seems to be veering dangerously close to contact with political reality, you can count on one of the President’s nannies to tug him safely back to dreamland.
This mission was entrusted to H. R. Haldeman and John Ehrlichman in the first term. For four turbulent years, they kept the “Do Not Disturb” sign firmly in place on the Oval Office door.
[…]
Regrettably, the Watergate affair—one of those minor disturbances that the guardians assured Mr. Nixon was beneath his notice—carried these good servants off, and made it necessary to find someone new to chase trouble from the White House doorstep.
It wasn’t easy, but this is a persevering President, and in time he found two new security blankets named Ron Ziegler and Al Haig. […]
[…]
During the transition period from Haldeman and Ehrlichman to Ziegler and Haig, the guard on the President’s door slipped; reality intruded. Connally got in, once or twice; Mel Laird, more often; Bryce Harlow, even more frequently, because he is so small he gets under the radar screen Haldeman and Ehrlichman had left behind.
7-: From the account of a press conference given in Hollywood by the U.S. actor Robin Williams (1951-2014)—account by Dan Lewis, published in The Grand Island Daily Independent (Grand Island, Nebraska, USA) of Saturday 14th April 1979:
He was reminded of some quotes from recent interviews in which he chastised television, using a scatological word to describe the quality on the tube. He softened the renewed assault:
“Television sometimes has a growing problem,” he responds. “It has a certain level. I could sit back and do ‘nanoo, nanoo’ all the time but I keep trying to expand.”
He likens television’s growth to an object trying to slip under the radar in its early days, now emerging with a frontal attack on the mass audience.
8-: From the column Mark Russell Comments, by the U.S. political satirist and comedian Mark Russell (Joseph Marcus Ruslander – 1932-2023), published in The Chapel Hill Newspaper (Chapel Hill, North Carolina, USA) of Friday 6th July 1979—the following is about U.S. President Jimmy Carter’s visit to Hirohito, Emperor of Japan:
The two leaders seemed to get along fine, and Hirohito offered to let his pilot fly Carter on a sightseeing trip around Japan. Carter thought it was a great idea until he learned that Hirohito’s pilot never learned to land.
Entertainment for the visiting Americans included the showing of the Gregory Peck movie “MacArthur”—only it was run backwards, so Japan wins.
The President had mentioned that he planned a stopoff in Hawaii for a private vacation. Hirohito suggested that the best way to go was to fly in there early Sunday morning—under the radar—before anyone is up.
9-: From a declaration made by a golf player called Ross Bartschy Jr., who had just won a tournament at Scioto Country Club, published in The Columbus Dispatch (Columbus, Ohio, USA) of Thursday 2nd August 1979:
“I didn’t hit my driver good all day,” said Bartschy, who will be 32 next month. “I hit only six good tee shots this afternoon.
“But I putted good and, when you hit it off the radar screen (off the tee), you’ve got to hit good irons and my irons were good.”
10-: From Benign Chaos: ‘A Tiny Diner Full of Gerbils’, an account of the Democratic National Convention, by G. B. Trudeau, written for, and published in, The Washington Star (Washington, District of Columbia, USA) of Wednesday 13th August 1980:
Delegates are kibitzing, they’re lobbying, they’re shouting, chanting; they’re making new friends, getting reacquainted with old ones; they’re reading, knitting, granting interviews, watching themselves on portable televisions. In fact, the only thing they aren’t doing is offering a hint of reassurance to the chairman that the speakers aren’t talking to themselves, that they haven’t dropped off the radar, trapped in some Bermuda Triangle where they can be neither seen nor heard.
11-: From Frogs nip Coogs in game-and-a-half, by Bud Kennedy, staff writer of The News, published in The Dallas Morning News (Dallas, Texas, USA) of Wednesday 18th February 1981:
Fort Worth—The Houston Cougars, flying along atop the Southwest Conference all winter, disappeared into the Bermuda Triangle Tuesday night.
This Bermuda is off Berry Street in Tarrant County and every time the Cougars happen this way they drop off the radar screen. Tuesday night they blew a 5-point lead in the last 74 seconds of a game as long as any in Southwest Conference history.
12-: From The End of the ‘Jimmy’ Story, published in The Washington Post (Washington, District of Columbia, USA) of Thursday 16th April 1981:
We apologize. This newspaper, which printed Janet Cooke’s false account of a meeting with an 8-year-old heroin addict and his family, was itself the victim of a hoax—which we then passed along in a prominent page-one story, taking in the readers as we ourselves had been taken in. […]
[…] The rock-bottom element of trust and the assumption of good faith that must exist in any professional relationship diminish the chances that you will spot a huge scam right away. You just do not read a many-paged memorandum from an apparently reliable reporter, relating her visit to and prolonged conversation with several people in great detail, and then inquire: “Say, did any of this actually happen?” Like some giant weapons system that can come in under the radar, Janet Cooke’s invention eluded detection by the normal protective procedures and techniques that are designed to catch far less spectacular but more commonplace slides and lapses.
13-: From an article by Martin Schram, of The Washington Post, about the Coalition for a Democratic Majority (CDM), a centrist faction within the Democratic Party, published in The Flint Journal (Flint, Michigan, USA) of Monday 29th June 1981:
Criticisms from these Democrats of the Republican administration have so far run the gentle gamut from non-combative to non-existent. Some of their number do not want to fight because they have switched: Reagan’s United Nations ambassador, Jeane Kirkpatrick, comes from the ranks of CDM; so do assistant secretary of state Elliott Abrams, assistant secretary of defense Richard Perle, and arms-control agency director Eugene Rostow.
Others—by the measure of Wahington’s cogniscenti [sic]—have been so quiet that they seem to have fallen completely off the radar screen of national politics.
word histories 