CA/Director of Flight Crew OperationsMay 7, 1968CB/Colonel Frank BormanVisit to RCS, Camden, New Jersey, May 3, 1968
I visited RCA, Camden, New Jersey on Friday, May 3 to review an engineering model demonstration of the VHF Ranging System. The test setup included the components for the Command Module (CM) and the Lunar Module (LM) located in two adjacent screen rooms. Signal strength between the two installations could be varied by changing a set of attenuators. The variation in signal strength was calibrated to provide a simulation of range. There was no pro- vision to incorporate the delay times associated with actual variation in range. Therefore, the actual range capability was not completely verified. Neither the LM nor the CM audio center was used.
The following results were noted: The system locked on at an indicated 252 nautical miles. After initial activation, the signal was lost at a range of approximately 425 nautical miles. The voice quality was good and no appreciable effect on readability was noted when the VHR Ranging was in op- eration. The “jitter” in readout associated with voice transmission which was evident in the breadboard model has been eliminated. Accuracy is pre- dicted to be ± 212 feet.
After the demonstration, the upcoming flight test program at White Sands was discussed. As a result of the discussion, it is suggested that a spacecraft audio center be employed on the ground so that a more realistic evaluation of voice quality can be made during the flight test. It is apparent that the only reliable and accurate demonstration and verification of the VHF Ranging System will occur during the flight test at White Sands.
One other item of interest is the fact that an ambiguity exists which will effectively limit the range readout of the system to around 327 nautical miles. Another area of some concern is the MIT software interface with the VHF Ranging System. It was noted, for instance, that the computer uses a 6000-ft nautical mile, while the VHF Ranging uses a 6080-ft nautical mile. MIT is aware of this, and I was told that the software program is proceeding without difficulty. Nevertheless, I do think it would be a good idea to hold direct discussions between MIT and RCA in the near future to make sure that there are no problems in integrating the system.