Ham radio

As Wikipedia says:
Amateur radio (also called ham radio) describes the use of radio frequency spectra for purposes of non-commercial exchange of messages, wireless experimentation, self-training, private recreation and emergency communication. The term “amateur” is used to specify “a duly authorised person interested in radioelectric practice with a purely personal aim and without pecuniary interest;.

I currently have a ham radio station, and also sometimes work REP‘s CS5RPT station.