Voice Modes
There are numerous operating modes in amateur radio, but the mode which comes most natural to us is that of voice. However, there is more to voice than just talking. There are a number of different communication methods which encompass the group of modes known as radiotelephone, or more commonly phone.
The first type of phone emission is FM, or Frequency Modulation. FM is very popular in the VHF and UHF segments. In an FM signal, the frequency of a quickly changing voice is modulated by a slowly changing radio signal. An FM signal contains many sidebands, and therefore takes up a great deal of bandwidth. Repeaters, which are devices which listen for a signal, and retransmit it on another frequency to extend communication range, use FM. Additionally, the majority of mobile and handheld radios for VHF and UHF bands are FM only. The top segment of the HF 10 meter band has areas designated for FM usage as well, but below that, band space and international range are too valuable to use FM because of the great signal size.
The next mode that we will discuss is Amplitude Modulation. Today, AM is popular with enthusiasts of older radios and those who enjoy the "golden sound" of a nice AM signal. AM was also originally the only voice operating mode. In an AM transmission, the amplitude of a varying audio signal is put into the amplitude very rapidly changing radio signal. AM consists of a carrier frequency, and two sidebands. As a result, AM is allowed in phone segments of the lower HF bands. Courtesy has created special segments for AM enthusiasts.
Finally, we discuss Single Sideband. SSB is the most popular operating mode on the HF bands, as well as somewhat popular on VHF / UHF when using base station equipment. Single Sideband is very efficient, which is why it is primarily used in the phone segments of the HF bands. In a SSB signal, the carrier of an AM signal is suppressed and all the power put into one sideband, which reduces the bandwidth requirement to 1/3 of the original AM signal. Both Upper Sideband and Lower Sideband are used by hams, and the accepted choice is dependent on the operating band.
No matter what phone mode you choose, ragchewing with someone across town, or across the world can be a blast.
Additional Voice Information