slight (0.1 cps) change in telemetry measurements is observed with RCA full power on. Final data reduction could not resolve a 0.1 cps variation. Therefore, it is not possible to determine the presence of RCA RF power from the JPL RF power monitor. A report of a discrepancy of 20 db in the prelaunch to ground station measurements was investigated. There were several problems in this area but all were resolved prior to launch. A 20 db pad was installed in the low gain antenna gantry circuit to reduce the relative JPL power compared to the RCA power. Previously, when the JPL transmission occurred, the JPL signal would capture the RCA receivers and prevent reception of video. This problem was experienced on the launch pad when the RCA low power mode was used. This is the only reference to a 20 db problem that can be determined. H. SCHEMATIC ANALYSIS OF EFFECT OF POSSIBLE TRANSMITTER 1. Conclusion Simultaneous fracture of Channel A and Channel B crystals will not, in all likelihood, cause the complete loss of signal experienced in RA-6. 2. Analysis Pursuant to a request to determine the cause of loss of transmission, it was first established that no available equipment could yield any evidence of L-band signal transmission from RA-6. Because the threshold of the measurements at Venus Site was such that any normal signal could have been sensed and presented to the I. P. A. at L-band, the FM modulator was investigated to determine what mechanism could account for the simultaneous loss of Channels A and B. Analysis of the FM modulator schematic discloses that the element most likely to be damaged by excessive shock is the frequency determining crystal. Even this supposition is unlikely since the JPL crystal was able to survive launch environment without the slightest change. Should such a shock, however, actually fracture the RCA crystals, it is evident from the schematic that the oscillators would continue to oscillate at some frequency close to the nominal value. This follows because the oscillator is a tuned base, tuned collector type. Furthermore, the frequency modulating varactor would now be able to deviate the oscillator over an extremely wide range which would most assuredly encompass a portion of the normal frequency spectrum and be evident in the data analysis. What has been outlined is a logical analysis based upon known observables. It is not impossible for crystal fracture to actually cause the effects that were seen on RA-6, but the probability of this happening is extremely remote. The normal operation of the P Sequencer Accumulator is illustrated in Figure L-1. The output of the 3.36 second flip flop is summed with the output of the 26.88 second flip flop in an adder circuit which gates on an SCR. Under normal operation, this pulse will then remain until the power supply for the sequencer is turned off. 2. Postflight Test A test was performed to determine the characteristics of this accumulator circuit under conditions of unusual voltage inputs. The input to the sequencer power supply was varied. It was determined that the input needed for reliable accumulator start and production of an accumulator pulse for Channel 8 telemetry, would be -20 vdc or more. Starvation of the accumulator initialization and accumulator pulse storage by the SCR will occur if the power supply input voltage is reduced to -5 vdc for a period of 10 milliseconds or more. 3. Observations of the Four Frames of Channel 8 Telemetry There was no evidence of an accumulator pulse during the 67 seconds of Channel 8 telemetry (Figure L-2) which included two full and two partial frames. This is normal if only the cruise mode on had been actuated; however, if the system had been in warmup, there were three opportunities for the pulse to appear at point 11 in frames 1, 2, and 3. Since it did not appear, an explanation of this is necessary to support other indications that the system may have been in warmup during this period of Channel 8 telemetry reception. During terminal mode the accumulator pulse appeared on the telemetry after warmup on Channel P. The appearance of the pulse was an indication that the P Channel accumulator was capable of operating. To explain the fact that the accumulator pulse did not appear in the telemetry during the inadvertent turn-on, it must be assumed that the sequencer was either reset or was not started. (One reset pulse was all that was required during the inadvertent turn-on to impede presentation of the pulse.) 1) If regulated input to the sequencer power supply drops to less than -5 volts for more than ten milliseconds, the sequencer will reset. 2) 3) When the regulated input to the sequencer power supply is less than -20 The following conditions could have caused the regulated supply on the r a) b) A heavy load on the HCR can reduce its output voltage from -27.5 vdc to If the accumulator was reset at least once after T +26. 5 seconds, and CHARACTERISTICS OF THE HIGH CURRENT REGULATOR B. A test was performed on a flight model high current regulator to determine its current carrying capability (see Table L-1). For a nominal unregulated voltage of -31.2 volts the regulator maintained a -27.59 volts output up to 5.8 amperes of load. With the input voltage kept at - 31 volts the output voltage dropped to 18. 8 volts as the load was increased to 7.5 amperes. Loading the HCR to 10 amperes will drive the output to 0 volts. A second test was performed where the load was maintained at 5. 8 amperes and it was determined that the HCR output would follow the input voltage, for example, V = 20.61, |