plural of signal strength

the (measured) strength of a radio signal as received by a radio or any other device receiving radio signals, such as a mobile phone.

plural of distress signal

An emergency signal sent by radio (or other means) from a ship or aircraft in distress or danger. / An indication of distress.

(historical) A kind of mechanical signal used on early American railroads, consisting of wooden balls, painted various colors, that were hoisted up and down a pole using a rope and pulley.

plural of ball signal

plural of smoke-signal

plural of smoke signal

(often pluralized) A method of long-distance communication sometimes used in ancient and undeveloped societies, consisting of messages conveyed by means of columns or intermittent puffs of smoke.

An event or emanation to which a sensing device gives an undesired positive response.