The attacker focus on a single frequency that the target uses and jam that with less power is called as spot jammer
. It is more efficient and effective jammer.
Rhino is a spot jammer
that uses time-sharing to provide a multi-channel capability.
To defeat a spot jammer
, the hostile transmitter may employ such measures as frequency agility, frequency hopping or wideband transmitter waveforms (i.e., spread spectrum).
This led to 'smarter' systems known as 'reactive jammers' or 'spot jammers
', which sensed electromagnetic activity and blocked those deemed dangerous.
With the right software, these all-digital radar emitters can be used as spot jammers
, directing pencil beams against "pop-up" threats.
Barrage noise jammers and swept frequency spot jammers
are not envisaged for deployment against missile systems.