Being interested in matters of defense and national security, and also, because I am always looking for useful insights for understanding current affairs, and for investing, I follow a number of military oriented websites and blogs. From these sources, I picked up the term, five by five (that is, 5 x 5,) which is analog radio communications shorthand for the grading of signal quality.
Analog signal quality, which is especially important to voice communications, is reported in two numeric scales: one for signal strength, and one for signal clarity, with number “1” being the worst and the number “5” being the best. Signal strength refers to the ability of a radio signal to get through (is the signal weak or strong?) Signal clarity refers to the ability of the signal to convey information as intended (is it garbled, or is it clear?) To say that a signal is “five by five,” or simply, “5 x 5”), means the signal has excellent strength and perfect clarity. “Five-by-five” is analog world tech-speak for “loud and clear.”
When communicating, think about signal quality. Shoot for 5 x 5.