Christopher Sebela

writer, wronger, rearranger

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 difficult to understand until it can no longer be heard as anything other than static.

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", "5 x 5", or "5-by-5"), by extension, has come to mean "I understand you perfectly" in situations other than radio communication. A further shortened form is "five by". Post-World War II, the phrase “Loud and Clear” entered common usage with a similar meaning.

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