For long distance communication (say, beyond line-of-sight), we bounce signals off the ionosphere. You can think of a radio signal traveling from my antenna, into the sky, bouncing off the the atmosphere, back down the ground - do this enough times and signals travel around the globe.

Sun activity can energize certain layers of the atmosphere differently - for instance during the day the "20 Meter Band" (the wavelengths you generate are roughly 20 meters long at around 14-MHz), is used because the sun is energizing a certain layer of the atmosphere to bounce signals off of. When it sets, that band 'goes away' - nothing to bounce off of, so we switch to different frequencies. During some sun activity, frequencies/bands we never get to use otherwise are available.

It's all black magic to be honest ;) Radio is fun in an analog sort of way of I getting to 'I used 20 watts of power and wire to talk to a guy in Italy'. It's a lot of fun.

For long distance communication (say, beyond line-of-sight), we bounce signals off the ionosphere. You can think of a radio signal traveling from my antenna, into the sky, bouncing off the the atmosphere, back down the ground - do this enough times and signals travel around the globe.

Sun activity can energize certain layers of the atmosphere different - for instance during the day the "20 Meter Band" (the wavelengths you generate are roughly 20 meters long at around 14-MHz), is used because the sun is engerizing a certain layer of the atmosphere to bounce signals off of. When it sets, that band 'goes away' - nothing to bounce off of, so we switch to different frequencies. During some sun activity, frequencies/bands we never get to use otherwise are available.

It's all black magic to be honest ;) Radio is fun in an analog sort of way of I getting to 'I used 20 watts of power and wire to talk to a guy in Italy'. It's a lot of fun.