Antenna Simulator E and NS outputs into 100-ohm loads, with switches set to simulate a negative return stroke.  Switch positions are: S1 - 5 Hz; S2 - mono; S3 - norm; S4 - max; S5 - N; S6 - no effect; S7 - max.  If  S5 and S7 are switched to min, then peak values E and NS will drop from the 2.0 and 1.0 V shown to 500 and 250 mV, respectively.  If  S3 is switched to inv, then E will invert; if S5 is switched to S, then NS will invert.