Five by five

Five by five is the best of 25 possible subjective responses used to describe the quality of communications. As receiving stations move away from an analog radio transmitting site, the signal strength decreases gradually while noise levels increase. The signal becomes increasingly more difficult to understand until it can no longer be heard as anything other than static. [Imel & Hart 2003, p.38.]

In voice procedure (the techniques used to facilitate spoken communication over two-way radios) a transmitting station may request a report on the subjective quality of signal they are broadcasting. In the military of the North Atlantic Treaty Organization (NATO) countries, and other organizations, the signal quality is reported on two scales; the first is for signal strength, and the second for signal clarity. Both these scales range from one to five, where one is the worst and five is the best. The listening station reports these numbers separated with the word "by". Five by five therefore means a signal that has excellent strength and perfect clarity — the most understandable signal possible.

"Five by five" (occasionally written "'5 by 5", "five-by-five" or "5-by-5") by extension has come to mean "I understand you perfectly" in situations other than radio communication, the way "Loud and Clear" entered slang, post-World War II. A further shortened form is "five by".

The term is arguably derived from the signal quality rating systems such as shortwave's SINPO code or amateur radio's RST. Given that this slang spans not only generations but also a spectrum of communications technologies (spark-gap transmitters, shortwave, radio telephone, Citizen's Band CD radio, cellular among others) and organizations (hobbyist, commercial, many military branches in different countries), there are many interpretations in popular misuse. No definitive interpretation of the phrase can be considered 'correct' anymore.

This reporting system is not appropriate for rating digital signal quality. This is because digital signals have fairly consistent quality as the receiver moves away from the transmitter until reaching a threshold distance. At this threshold point, the signal quality takes a severe drop and is lost. [Imel & Hart 2003, p.39.] This difference in reception reduces digital quality to more of a nonsensical "Can you hear me now" question. (The only possible response is "Yes"... otherwise there is just dead air.) This sudden signal drop was also one of the primary arguments of analog proponents against moving to digital systems. However, the "five bars" displayed on many cell phones does directly correlate to the signal strength rating.

Example of a radio readability transmission

This is an example of how the system might be used, using British military voice procedure. Station call sign "Alpha One" wishes to know how well another station, "Alpha Two" is receiving him.

:Alpha One: "Alpha Two, Alpha One. How do you read me? Over."

:Alpha Two: "Alpha One, Alpha Two. I read you five by five. Over."

Also know as "Fivers" by BEB

Colloquial use

*The term "five by five" was used by the character Faith (played by Eliza Dushku) who was a "Slayer" in the WB television show "Buffy the Vampire Slayer" and its spinoff "Angel". Faith Lehane, a native of Boston, Massachusetts, used it frequently as slang meaning that things were understood, good or, possibly, even. However the phrase was not fully understood by other characters (Tara Maclay: "Five what by five what?", Willow Rosenberg: "That's the thing, no one knows." -This Year's Girl) "Five by Five" was also the title of an "Angel" episode which prominently featured Faith.
*"Five by five" was used frequently in testing communications links between the US and Soviet Union in the 1964 film "Fail Safe".
*The phrase "In the pipe, five by five" is used by the dropship pilot, Ferro, in the movie "Aliens" to report that the drop is proceeding as planned. It was later used by the Terran dropship in the Blizzard Entertainment PC game "StarCraft" as one of many quotes from "Aliens".
*The term was used in the movie "Clear and Present Danger" when the Special Ops team (callsign KNIFE) led by Captain Ramirez communicated to John Clark (callsign VARIABLE), the CIA coordinator in Bogota for the operation.
*Used also in several episodes of the TV series "Alias", e.g., the fourth season episode "Nightingale" (Marshal says, "Copy, five by five, Phoenix standing by" in response to a mission update) and the fifth season episode "Solo" (Marshall says five by five again).
*The phrase was frequently used by EarthForce personnel on the TV series "Babylon 5", presumably due to the characters' military background.
*Another instance was in the Gene Roddenberry series, "Andromeda". In the second season episode "All Too Human", Trance Gemini uses the phrase to indicate that the ship is battle-ready.
*In the Stargate Atlantis season 3 episode First Strike (Part 1), in response to the question "Dr. McKay, can you read me?" from Maj. Lorne, Dr. McKay responds with: "Five by five. Lorne, you in position?"
*In the Stargate Atlantis season 4 episode Lifeline, in response to a question from Colonel Carter, Colonel Ellis responded with "5 by 5".
*In the Stargate Atlantis season 4 episode Quarantine, Colonel John Sheppard tells Teyla Emmagan that Atlantis is broadcasting a warning signal "5 by 5" that the city is under quarantine.
*The phrase "five by five" — and sometimes "five by" for short — is also used repeatedly by the police troopers in Stephen King's 2002 novel, "From A Buick 8".
*The term was used liberally in the film "Event Horizon".
*The phrase is heard in "The Twilight Zone" episode "The Parallel", from the fourth season (March 1963), when two officers discuss a patient's condition, indicating he is healthy.
* In the movie "Contact", Jodie Foster's character, Dr. Ellie Arroway, uses the term to signify clear communication between her space pod and mission control.
* In "Sly Cooper 3: Honor Among Thieves", at the start of the game Sly says to Bently, "Alright, I'm five by five," indicating everything is set for the mission.
* In the video game "Halo", in "The Maw", Echo 4-19 says, "I read you five by five," as she approaches Master Chief for pick-up.
* In JAG episode 1.09, "Boot", Lt. Meg Austin uses the phrase "five by five, sir" in response to a command by Lt. Harm Rabb.
* In "The Thunderbirds", episode 31 "Ricochet" it is used by one of the members of International Rescue
* In the CBS series "The Unit" Season 2 Episode 21; the character Mack 'Dirt Diver' Gerhardt when questioned about his mental state tells his commanding officer, Colonel Tom Ryan, "...but I'm five by five and mission ready" to signify his mental health.
* In the movie "Spartan", David Mamet's cameo character responds to Val Kilmer "five by five" when asked how he is doing.
* In the computer game Crysis the Raptor Team leader Prophet uses the phrase in the introductory phase of the game.
* In the 1998 film 'Wag the Dog' Robert De Niro's character uses the phrase over the phone to the president after a close call with a CIA interrogator.
* In the Stargate SG-1 television series, the term "five by five" was used by Sgt. Walter Harriman (Gary Jones) regarding U.A.V and M.A.L.P telemetry, and standard radio signal.
* In the Stargate SG-1 season 4 episode 'tangent' lt. col. samantha Carter replied "We hear you, five by" to col. Jack O'neill.
* In the computer game Company of Heroes, American riflemen will occasionally acknowledge an order using the phrase "Five by Five."

Notes

References

Imel. Kathy J. & Hart, James W. , P.E. [http://www.safecomprogram.gov/NR/rdonlyres/24F0E8A6-CFC4-43A4-8053-EE287D87D2C5/0/Understand_Wireless_Comm.pdf Understanding Wireless Communications in Public Safety] : A Guidebook to Technology, Issues, Planning, and Management for the National Law Enforcement and Corrections Technology Center (Rocky Mountain Region) [http://www.nlectc.org/txtfiles/wirelessasc.html TEXT]