SSB vs. FM — What's the Difference?

FM — Frequency Modulation

FM encodes audio by varying the frequency of the carrier wave. The result: clean, natural audio at good signal levels with an abrupt "cliff edge" when signal strength drops — FM goes from clear to unreadable quickly as the signal weakens. FM is used on VHF and UHF for local operation — repeaters, handheld-to-handheld simplex, and most day-to-day Technician operating.

FM requires more bandwidth than SSB (typically 15–25 kHz versus 2.7 kHz for SSB), which is why it is practical on VHF/UHF bands with ample spectrum, but not efficient enough for the crowded HF bands where long-distance contacts happen.

SSB — Single Sideband

SSB is a form of amplitude modulation (AM) that transmits only one of the two sidebands and suppresses the carrier. This makes SSB roughly 3× more power-efficient than AM for the same audio content — and allows a signal to travel much farther for the same transmit power. SSB is the dominant voice mode on HF bands. On 20 meters (14.225 MHz), SSB contacts with Europe, South America, and the Pacific are routine during good conditions.

The trade-off: SSB audio is less forgiving than FM. Tuning must be precise (SSB signals sound distorted if you are even 100 Hz off frequency), and the audio quality is more variable with propagation conditions. SSB receivers are also more complex than FM receivers.

Why Technicians Use FM and General/Extra Use SSB

The frequency ranges match the mode: VHF/UHF (Technician territory) have enough spectrum for FM's wider bandwidth and primarily serve local communication where FM's clean audio is an advantage. HF (General/Extra territory) has narrower channels, longer distances, and variable propagation where SSB's efficiency matters. This is not a rule — SSB exists on VHF for weak-signal DX work at 144.200 MHz — but it is the practical pattern for most operators.

• Can I use SSB on 2 meters as a Technician?
  Yes. Technicians have full privileges on the 2-meter band including SSB on the weak-signal sub-band (144.100–144.200 MHz). The 2-meter SSB calling frequency is 144.200 MHz. This is a specialized operating niche — most Technicians never explore it — but it is fully legal and can produce remarkable long-distance contacts during sporadic-E or tropospheric ducting events.