ua All oscilloscopes were triggered simultaneously by the DC trigger device located in the primary cathode follower and connected directly to the receiving antenna, The 2 micro-second delay line was added to permit the leading edge of the waveform to be recorded. In order to establish a definite time relationship between the reception of the signal and the triggering of a given device such as a counter or transmitter, a time marker pip, generated by the delay trigger from one of the oscilloscopes, is fed through the 2 micro-second delay line and superimposed on the initial portion of the received waveform. PROCEDURE 4 All oscilloscopes are calibrated d4gainst a known frequency stan~ — dard for sweep linearity. The cathode follower triggering system is set to trigger approx-~ imately 6 db. above the noise level, The vertical deflector of the oscilloscopesare set to receive the predicted field strength. RESULTS The Eniwetok station was in operation cor (iia (CHEROKEE). No data was recorded due to an early trigger from some unknown source. CONCLUSIONS Since this event was an air drop and having only basic timing it was not known at the time that the waveform recorded was not correct. Consultation with other projects involved in the same research vealed the error, re- Since the equipment is a single-shot trigger device and unable to distinguish between atmospheric noise and the electro- COPIED/uy Magnetic pulse, a certain percentage of false data can be expected. > LANL Re n- i> 4" co