This wasn't an easy task since it isn't until 90,000 cycles per second, or 9kHz, that radio begins. The familiar A.M. radio band starts around 560 kHz, or 560,000 cycles a second, with all present day radio-telephone services far, far above this. If you want to define radio, generating a rapidly oscillating, high frequency electromagnetic wave is certainly a prerequisite. I have archived a nice NASA diagram. Click here .
Most folks do.
An electrical current or signal always has a magnetic field associated with it, either in a wire or out in space when it is radiated from an antenna. This modulated signal does NOT go straight up, rather, these big and small loops of electrical energy, depending on how low or high the frequency, are whipped out 360 degrees from an omnidirectional antenna such as the one above. Or focused like a light beam from a directional antenna. Let's review before we look at how early radio developers developed high frequency waves. At the top of this page we saw how Morse used conduction, to wirelessly pass a signal without using the atmosphere.