Other radars normally produce what is known as a 'spoke' (not 'spike') which originates at you and expands gently out towards the top of the screen on the azimuth of the TX. Not a 'normal' occurrence since powerful mil radar frequencies are far away from civil but sometimes a harmonic will pop up. Civil stuff is pretty low-powered and
may produce one. You'll never know until the missile hits you........................,
.
Radar jargon - 1