Scout needs 2 OEW and lock-on on target (actually now when EW is more linear - 1 point should do!)
friendly ship needs 2 OEW and lock-on on target
Scout needs 1 OEW and lock-on on friendly
...and then friendly ship gets half OEW scout has on target. Scout must be within 30 hexes of both units (both at time of declaration and firing).
Note that lock-ons are needed - so no offensive ElInt use versus active Jammer (unless by Ancients or other Minbari).
Lowering scanner power is possible if EW is assigned and EW displays are not updated when scanner power is lowered.