The amplitude or power of a transmitted signal, which the new antenna improves for better measurement.Signal strength refers to the amplitude or power of a transmitted signal, typically measured at a receiver. In physics and engineering, it quantifies how much of the original signal survives propagation through a medium, whether that medium is free space, a cable, or a complex structure like the Moon. The concept is central to any measurement system: a stronger signal relative to noise allows for more precise detection and analysis of the information it carries.
The quantitative study of signal strength emerged with radio communications in the early 20th century, notably through the work of engineers like Guglielmo Marconi and later the development of the decibel scale by Bell Labs in the 1920s.
Signal strength is usually expressed in decibels relative to a reference (e.g., dBm for power). It depends on the transmitter power, the gain of the antennas, the distance traveled, and losses in the medium. In practice, improving signal strength often involves increasing antenna gain, which focuses the radiated energy in a desired direction, or reducing losses in the transmission path.
Signal strength is used in wireless communications (Wi-Fi, mobile networks), radar, and radio astronomy, where optimizing antenna design directly improves the sensitivity of measurements, such as detecting faint gravitational wave signals using the Moon as a detector.
In radio astronomy, a signal from a distant source can be billions of times weaker than the noise generated by the receiver itself, yet it can still be extracted by integrating over long periods.
