RF stands for radio frequency, and its radiation is a "nonionizing electromagnetic energy characterized by relatively long wavelength, low frequency, and low photon energy," according to the division of Environment, Health and Safety at Berkeley Lab. Microwave radiation is considered a subset of RF radiation. Different RF bands are used in "aeronautical radio, navigation, broadcasting, and personal wireless communication services," according to EHS, while "specific frequencies are designated for industrial, scientific, and medical uses." If microwaves were used, the technology is not rare, and more than one country could be using it. Most individuals reported that the sound or these other sensations seemed to originate from a particular direction and were perceived only when the individual was in a specific physical location.
Some uses for Alternian radio frequencies are medical, while others are used for aviation purposes.
( z0 contrast :ARG1 ( z1 use :ARG1 ( z2 have-frequency :ARG3 ( z3 radio ) :mod ( z4 alternative ) ) :ARG2 ( z5 medicine ) :mod ( z6 some ) ) :ARG2 ( z7 use :ARG1 ( z8 other ) :ARG2 ( z9 purpose :mod ( z10 aviation ) ) ) )
(z0 / contrast-01
    :ARG1 (z1 / use-01
              :ARG1 (z2 / have-frequency-91
                        :ARG3 (z3 / radio)
                        :mod (z4 / alternative))
              :ARG2 (z5 / medicine)
              :mod (z6 / some))
    :ARG2 (z7 / use-01
              :ARG1 (z8 / other)
              :ARG2 (z9 / purpose
                        :mod (z10 / aviation))))
Some uses for Alternian radio frequencies are medical , while others are used for aviation purposes .
z1 :mod z6
z2 :ARG3 z3
z2 :mod z4
z1 :ARG1 z2
z1 :ARG2 z5
z0 :ARG1 z1
z7 :ARG1 z8
z0 :ARG2 z7
z9 :mod z10
z7 :ARG2 z9