Which statement is true regarding PL-259 type coax connectors?

The statement about PL-259 type coax connectors being commonly used at HF frequencies is accurate because these connectors are specifically designed to work well with the impedance and frequency characteristics of HF radio bands. The PL-259 is a type of coaxial connector often associated with amateur radio and other communication applications operating primarily in the HF range, from 3 to 30 MHz.

Due to their construction, PL-259 connectors provide a low-loss connection that is effective at HF frequencies, making them a prevalent choice among amateur radio operators for linking radios to antennas. They are also compatible with the typical 50-ohm RF coaxial cables used in many radio installations.

In contrast, while PL-259 connectors can function at UHF frequencies, they are not optimized for that range compared to other types of connectors. Their design does not ensure water tightness, though certain variations can be waterproofed with additional sealing. Moreover, they are not a bayonet type connector; instead, they feature a screw-on mechanism for attachment.