The July 2021 issue of RadioUser covers the depths of the Sea to the vastness of Outer Space. We have some up-to-the-minute reviews of new radio software and the latest CB aerials, analysis of the most pertinent new discussions and emerging issue in radio, and some outstanding features on a range of topics, from QSL card-collecting and remotely-controlled ATC towers to radio signals from Jupiter, submarine comms, private short wave broadcasters in Europe, the pioneer days of radio, and the most recent digital broadcasting innovations.