As long as you are moving*, you won't show up on radar.
*moving entails walking, sprinting, ADS strafing with SMGs shotguns and pistols, ADS strafing with ARs and LMG only with Adjustable Stock --- Me and my uncle went ridin' down, South Colorado, West Texas bound BO2 Combat Record - http://tinyurl.com/cxvk9xr
Just in case you don't know TC, when looking at the minimap, the yellow arrow that indicates who you are will "fade" when ghost is working. When it isn't working, it will be a solid yellow line. --- Only idoits can't spell.