Final answer:
Touching the antenna of a radio can improve reception because your body extends the antenna, increasing its ability to receive signals. This highlights the effect of antenna size and placement on signal reception. Locating and disabling a disruptive radio source involves tracing emissions and potentially deactivating the source.
Step-by-step explanation:
When touching the antenna of a radio that is tuned to the edge of a station's discernible range, and the reception improves, it is likely that the act of touching the antenna is helping to boost the signal. Your body is acting as an extension of the antenna itself, increasing its length and, consequently, its ability to receive signals. This exemplifies the importance of antenna size and placement as it relates to radio wave interference and the quality of signal reception.
To locate an offending radio source, investigators may use directional antennas and signal strength meters to trace the source of unwanted emissions. If the source is found to be disruptive or illegal, it may be necessary to take measures to disable the radio source to prevent further interference. Radio telescope operators similarly may identify extraterrestrial signals like those from quasars by distinguishing characteristics such as signal strength, spectrum, and modulation, as well as by verifying the lack of correlation with known terrestrial sources.