PDS_VERSION_ID = PDS3 RECORD_TYPE = STREAM OBJECT = TEXT PUBLICATION_DATE = 1999-09-07 NOTE = " E-mail and other messages concerning MGS Radio Science on or about 1997/092." END_OBJECT = TEXT END From trish@rodan.jpl.nasa.gov Wed Apr 2 00:08:25 1997 Received: from 128.149.43.3 (james.jpl.nasa.gov [128.149.43.3]) by rodan.Jpl.Nasa.Gov (8.8.5/8.6.6) with SMTP id AAA15290; Wed, 2 Apr 1997 00:08:18 -0800 (PST) Message-Id: <199704020808.AAA15290@rodan.Jpl.Nasa.Gov> Date: 02 Apr 97 00:13:43 -0800 From: Trish Priest Subject: USO Test #10 - Test Report To: Richard Simpson , Len Tyler Cc: Salvatore F Abbate , Sami Asmar , Tom Thorpe , Joe Twicken X-Mailer: QuickMail Pro 1.0.1 X-Priority: 3 Reply-To: Trish Priest Content-Type: text/plain; charset="iso-8859-1" Status: RO Hello, The first part of the track was used to retransmit data from the KaBLE/USO Test on DOY 088. This went smoothly. At the beginning of the USO Test, the DSP gave a warning message: NO BUFFERS AVAILABLE FOR ALLOCATION We have seen this error message before, only during retransmissions. It does not interrupt the data, so we continued with the experiment. Apparently, however, this affects the data going into the SCP (Station Communications Processor). Therefore, the station had to reboot the DSP in order to clear the error. (They checked with us first.) As a result, we only got data from 092-05:57:30 to 092-07:00:00. This data was error-free. I have also completed a retransmission of the data, so no records should be missing. No spurs were present, but the carrier was very broad. Telemetry and ranging were both off. Also, KaBLE was on for the entire USO Test. It was referenced to a combination of the USO and the VCO. I left a message for Sal about the DSP error. I believe that it only happens during or after a retransmission has taken place. I will follow up with Sal on Wednesday. -Trish -------------------------------------------------------------------------- From trish@rodan.jpl.nasa.gov Wed Apr 2 09:42:25 1997 Received: from 128.149.43.3 (james.jpl.nasa.gov [128.149.43.3]) by rodan.Jpl.Nasa.Gov (8.8.5/8.6.6) with SMTP id JAA16314 for ; Wed, 2 Apr 1997 09:42:22 -0800 (PST) Message-Id: <199704021742.JAA16314@rodan.Jpl.Nasa.Gov> Date: 02 Apr 97 09:47:48 -0800 From: Trish Priest Subject: DR for last night To: Dick Simpson X-Mailer: QuickMail Pro 1.0.1 X-Priority: 3 Reply-To: Trish Priest Content-Type: text/plain; charset="iso-8859-1" Status: RO In case you need this for your report, the DR number for last night's problem is G01990. I will see Sal at our 11:00 AM meeting. -Trish ------------------------------------------------------------------------- From joe Thu Apr 3 15:06:01 1997 Received: from neptune.stanford.edu. (neptune.Stanford.EDU [36.10.0.149]) by nova.stanford.edu (8.8.5/8.8.4) with SMTP id PAA16391; Thu, 3 Apr 1997 15:05:47 -0800 (PST) Date: Thu, 3 Apr 1997 15:05:47 -0800 (PST) From: Joe Twicken Message-Id: <199704032305.PAA16391@nova.stanford.edu> To: David.D.Morabito@cc2mhb.jpl.nasa.gov, hinson@nova.stanford.edu, joe@nova.stanford.edu, john@oberon.jpl.nasa.gov, len@nova.stanford.edu, rsimpson@nova.stanford.edu, trish@qmail.jpl.nasa.gov Subject: USO Test #10 (97/092) Status: RO I have processed the ODS data from 97/092. This ODS was recorded at DSS 15. The data were acquired as part of USO Test #10. The SNR was approximately 61 dB/Hz during the Test. This was the sixth USO test since the MGS HGA was deployed. All files for processing this ODS were recorded in the MgsDB database. The first 57 minutes of USO Test data were not recorded due to an error at the DSP. At the beginning of the USO Test, the DSP gave a warning message: NO BUFFERS AVAILABLE FOR ALLOCATION. The station had to reboot the DSP in order to clear the error and the recording did not begin until nearly half of the test was over. The ODS was acquired at DSS 15 from 05:57:30 to 07:00:00 at 5000 samples per second in mode 2 (1250 12-bit samples/second for each of 4 A/D's). KaBLE was on during this test, referenced to a combination of USO and VCO. Telemetry and ranging were both off. There were no missing records in the ODS. I used the spk_c_970129-970510 SP-kernel file to steer the data. This file was created on 97/083. The POCA file was fixed with our "salvagePoca" program, but hand modification of the POCA file was also required. At time tag 21639, it was necessary to modify the ramp rate from -0.07090 Hz/sec to -0.07089 Hz/sec in order to maintain consistency with remaining POCA readback frequencies. It has also been necessary to make such a 10 microHertz/sec modification to a POCA ramp rate a few times in the past, in order to match the POCA readback frequency at the time of a ramp rate change. The cause of this 10 microHertz mismatch is not known. In addition to that POCA error, there was the usual collection of missing/duplicate POCA time tags and incorrect POCA readback frequencies. These were all handled by the salvagePoca program. The power spectra of the USO Test #10 signal showed a comb of frequency spurs which tracked the carrier throughout the Test. I have not seen this behavior prior to this Test. The primary spurs were at 60 Hz and many harmonics of 60 Hz on both sides of the carrier. The 60 Hz spurs were approximately 38 dB below that of the carrier and the harmonics were all 42 or more dB below the carrier. In addition to these spurs, the steered data showed numerous other lower-level spurs tracking the carrier. The closest spurs to the carrier were a set of side-by-side spurs which appeared both above and below the carrier with an offset of approximately 30 Hz. The spurs which we have previously seen at approximately 650 Hz from the carrier were not evident in this Test. A large amplitude modulation with a period of about 6-12 minutes is evident in the carrier amplitude estimates. The peak-to-peak variation during this test was on the order of 1-2 dB. I estimated the USO frequency to be 8423152935.19 Hz. The best linear fit to the USO frequency since 96/332 has a slope of 0.253 Hz/day. This fit is actually quite good. The 1-sigma error between our USO frequency estimates since 96/332 and the best linear fit to them is 0.23 Hz. The Allan deviation for this recording is shown below. The SNR during the acquisition of data was approximately 61 dB/Hz. This value may be somewhat underestimated due to the many spurious frequency components in the vicinity of the carrier. I did not compensate for the spacecraft spin cycle. AT ALL INTEGRATION TIMES, THIS WAS THE BEST USO TEST PERFORMANCE TO DATE. t (sec) AD ------ ---------- 0.4096 2.6101e-13 1.6384 1.7441e-13 3.2768 1.4299e-13 6.5536 1.1348e-13 26.2144 8.9345e-14 Plots, as usual, are in the notebook in room 222. Joe