(1) In
cellphone terminology, a jammer is a device that
blocks transmissions by creating interference. The jammer emits signals in the
same frequency range that cell phones uses, and within the range of a jammer a
cellphone user may lose their signal.
(2) In
satellite terminology it is a
mobile ultrahigh-frequency (
UHF) high-power noise source that
can be used to jam satellite
antennas or receivers.