Which type of modulation is commonly used for VHF and UHF voice repeaters?

VHF and UHF voice repeaters almost universally use Frequency Modulation (FM) or Phase Modulation (PM). These modes provide clear, static-free local communications and benefit from the "capture effect," where the receiver locks onto the strongest signal and suppresses weaker interfering ones. Technically, many modern radios marketed as "FM" actually use Phase Modulation (PM) to generate the signal, as PM naturally provides pre-emphasis to the audio, resulting in the same characteristics as FM. AM and SSB are not used for standard repeaters because they are highly susceptible to static and require precise tuning.