Chinese radio signals suddenly appear on Japan's FM broadcast
According to Japanese media outlet Nankai Broadcasting, on June 1, in certain areas of Kagoshima Prefecture, Chinese-language broadcasts were unexpectedly received on FM radio receivers.
The cause is a special type of ionosphere known as the sporadic E layer (Espo), which suddenly forms at an altitude of about 100 kilometers above the Earth's surface. The sporadic E layer is a phenomenon that occasionally occurs during summer and can reflect specific wavelengths of radio waves.
The sporadic E layer appears suddenly and has high electron density even within the ionosphere, enabling it to reflect VHF (very high frequency) ultra-short waves used in FM broadcasting, allowing radio signals to travel to distant regions where FM signals normally cannot reach.
According to the National Institute of Information and Communications Technology of the United States, when the sporadic E layer develops excessively, VHF radio waves—typically not reflected by the ionosphere, such as those used in television broadcasts or FM radio—can be anomalously reflected and propagated over long distances, causing interference with distant broadcast stations.
Car radios are particularly susceptible. Especially during road trips, if wireless signals weaken slightly due to terrain or buildings, they may be overwhelmed by strong overseas signals, resulting in interference and noise.
Suddenly, the FM broadcast channel of Nankai Broadcasting was replaced by radio signals originating from China, with Chinese broadcasts being played through the radio.
Original source: toutiao.com/article/1866776609312780/
Disclaimer: This article represents the personal views of the author