5- Transmitting modulation and bandwidth 

5- Transmitting modulation and bandwidth (and receiving them)

On VHF/UHF most transmissions are in FM narrow 12.5 kHz bandwidth, 70cm can be in FM wide 25 kHz. Most repeaters work in FM or digital modes.

On HF, the predominant mode for voice communication is SSB-Single Side Band. That can be Lower Sideband on frequencies below 10 Mhz and USB- Upper Side Band above. This allows signals to propagate further for the same power and is more readable too.

You may need to tune your radio accurately to get the right tone or they’ll sound boomy or squeaky, have a play you’ll soon figure it out. The tuning is the opposite way round for USB compared to LSB.

There are exceptions to this, Digital Modes like FT8, WSPR, SSTV are always USB regardless, that’s the convention.

https://www.electronics-notes.com/articles/radio/modulation/types-techniques-am-fm-pm-psk-qam.php