Learn in the textbookInfrastructure Foundations of Mobile Communications
DefinitionThe platinum band (プラチナバンド) is the popular name for the easy-to-connect 700 MHz to 900 MHz bands among the frequencies mobile phones use in Japan.
ExplanationFrequency is how many times a radio wave oscillates in 1 second, measured in MHz or GHz. Since 1 GHz equals 1000 MHz, the platinum band sits below 1 GHz. That low range is what helps the signal reach spots behind buildings and indoors.
AnalogyStand behind a wall and you can still catch a deep voice from the far side, while a high one is harder to hear. Radio waves show a similar tendency.
Memory hookThe name comes from platinum, likening these frequencies to a rare and highly valued metal.