My opponent has the active turn. My trooper (A) is equipped with a jammer and is in close combat with an enemy warband trooper (B). Another enemy trooper (C) activates and moves within the ZoC of trooper A, with the jammer... ...can I declare that I am using the jammer on trooper C, as it requires no LoF?
No, If a model is in the "engaged" state, then they may only declare skills that the engaged state allows them to, or a special skill that states otherwise. Second bullet under "Effect" http://infinitythewiki.com/en/Engaged
