Short Wave Radio Receivers

Sunspot activity dipped over this past week, but now it on its way back up. On July 20, five sunspot groups were visible, but on July 21, only groups 1251, 1254 and 1259 remained. On July 24, new sunspot group 1260 appeared, and the next day, 1251 disappeared. On July 26, groups 1254 and 1259 [...]