RV146 (Astrometric/Geodetic VLBA-146) 2021 MAR 24 18:00 UTC DOY 083 Notes prepared by David Gordon (GMU/USNO) and Ed Himwich (NVI/GSFC) Special notes for this session: =============================== This session will use the RDBE/DDC/Mark6 system at the VLBA sites, as in previous RV sessions. The X-band frequencies are: 8365.75, 8445.75, 8805.75 and 8925.75 MHz, and spans 560 MHz. The S-band frequencies have been changed from the last few RV's to accommodate HOBART26. They are: 2212.75, 2242.75, 2282.75 and 2372.75 MHz. It is expected that HOBART26 will get only the first 3 S-band channels due to RFI issues. The ending in .75 MHz is necessary at the VLBA stations. Therefore it will not be possible to monitor phase cals using the 10 kHz filters. RV146 will record 8 16-MHz bandwidth channels using 2-bit sampling. The bit rate will be 512 Mbits/sec. The data will be correlated at the VLBA using the VLBA DiFX software correlator. There are 6 non-VLBA stations scheduled - HARTRAO, HOBART26, NYALE13S, ONSALA60, SESHAN25 and WETTZELL. HOBART26 and SESHAN25 are new to the RV sessions. NYALE13S is also new. It is being tagged along to replace NYALES20, which cannot observe at this time. These 6 non-VLBA stations should see the "Special operations notes for non-VLBA stations" section below for special instructions. To facilitate fringe-finding, there are some long scans on fairly strong sources with most antennas at the beginning and near the end of the schedule. All stations please try to be onsource and recording data for these scans. These scans are: Source Start DURATIONS name yyddd-hhmmss Br Fd Hh Hn Kp La Mk Nl On Ov Pt Sc Wz Ho Sh Ns 0016+731 21083-180000| 306 307 300 300 300 315 304 319 301 300 309 311 337 337| 0446+112 21083-180637| 389 300 394 393 394 367 393 374 395 395| 1741-038 21083-180803| 342 320 337 329 300 342 | 0016+731 21084-174434| 421 385 300 410 373 430 400 416 373 436 394 300 436| 0446+112 21084-175233| 442 442 442 442 442 442 442 442 442| 1741-038 21084-175430| 325 325 325 325 325 325 | We are again using the 'Fill' scheduling option. 'Fill' is run after a schedule is finished in the normal manner. It increases the scan times at stations, when possible, based on how much idle time each station has before its next scan. We used a 'FILL_OFF' margin of 5 seconds. Using 'Fill' on the original schedule, the average observing time increases from 46% to 57%, and the average idle time decreases from 25% to 13%. The observing time increases most at the faster antennas and least at the slower antennas. Purpose ======= This is the second of six coordinated astrometric/geodetic sessions in 2021 that use the full 10-station VLBA plus several geodetic stations capable of recording VLBA modes. This year's series is a continuation of the highly successful RDV series begun in 1997. These are now being run under the USNO's VLBA time allocation. These sessions are being coordinated by the geodetic/astrometric VLBI programs of USNO, NASA and NRAO. They have been designed so that the same data set may be used by each agency for its particular goals. Schedule information ==================== This is a new schedule generated by David Gordon at USNO using sked. Schedule file name: rv146.skd At the IVS Data Center (ftp://cddisa.gsfc.nasa.gov/vlbi/ivsdata/aux/2021/rv146): Sked file: rv146.skd Text file: rv146.txt At the VLBA/NRAO: Sked file: rv146.skd Vex file: rv146.vex Text file: rv146.txt Summary file: rv146.sksum This session uses the VLBA stations and 6 IVS stations. The IVS stations are: HARTRAO, HOBART26, NYALE13S, ONSALA60, SESHAN25 and WETTZELL. NYALE13S has been tagged along in place of NYALES20. Below is the sked summary. Key: Br=BR-VLBA Fd=FD-VLBA Hh=HARTRAO Hn=HN-VLBA Ho=HOBART26 Kp=KP-VLBA La=LA-VLBA Mk=MK-VLBA Nl=NL-VLBA Ns=NYALE13S On=ONSALA60 Ov=OV-VLBA Pt=PIETOWN Sc=SC-VLBA Sh=SESHAN25 Wz=WETTZELL Br Fd Hh Hn Ho Kp La Mk Nl Ns On Ov Pt Sc Sh Wz Avg % obs. time: 57 63 53 59 56 63 64 55 59 32 61 61 64 60 46 62 57 % cal. time: 5 5 3 5 3 5 5 5 5 3 5 5 5 5 4 5 5 % slew time: 27 25 41 27 30 25 25 25 26 2 24 26 24 25 35 11 25 % idle time: 10 6 3 8 9 6 5 14 9 63 9 7 5 10 14 21 13 total # scans: 465 454 243 456 266 453 447 420 449 218 437 445 448 429 357 419 400 # scans/hour : 19 19 10 19 11 19 19 18 19 9 18 19 19 18 15 17 17 Avg scan (sec): 106 120 187 111 182 120 124 113 114 128 120 119 124 120 111 129 126 # data tracks: 16 16 16 16 16 16 16 16 16 16 16 16 16 16 16 16 # Mk5 tracks: 16 16 16 16 16 16 16 16 16 16 16 16 16 16 16 16 Total TB(M5): 3.16 3.48 2.91 3.24 3.11 3.49 3.54 3.04 3.28 1.78 3.35 3.38 3.56 3.29 2.55 3.45 3.16 # OF OBSERVATIONS BY BASELINE | Br Fd Hh Hn Ho Kp La Mk Nl Ns On Ov Pt Sc Sh Wz Total ------------------------------------------------------------------------------------------ Br| 285 0 303 9 293 307 240 331 139 154 311 304 228 92 128 3124 Fd| 3 272 7 416 410 237 335 81 93 358 415 282 45 79 3318 Hh| 12 196 1 3 0 8 14 50 1 3 17 103 56 467 Hn| 3 253 275 150 366 113 177 241 273 348 52 165 3003 Ho| 10 8 31 3 3 14 9 8 4 146 22 473 Kp| 414 257 319 79 91 385 420 252 49 74 3313 La| 234 346 85 102 367 442 271 50 88 3402 Mk| 194 69 57 290 238 136 130 42 2305 Nl| 104 137 302 344 316 50 126 3281 Ns| 129 88 86 84 67 104 1245 On| 94 98 149 107 377 1829 Ov| 373 219 56 76 3170 Pt| 268 50 84 3406 Sc| 29 141 2744 Sh| 108 1134 Wz| 1670 Number of 2-station scans: 444 Number of 3-station scans: 239 Number of 4-station scans: 117 Number of 5-station scans: 76 Number of 6-station scans: 80 Number of 7-station scans: 58 Number of 8-station scans: 61 Number of 9-station scans: 67 Number of 10-station scans: 100 Number of 11-station scans: 39 Number of 12-station scans: 29 Number of 13-station scans: 11 Number of 14-station scans: 4 Number of 15-station scans: 0 Number of 16-station scans: 0 Total number of scans: 1325 Total number of obs: 18942 INTENSIVE BREAKS ================ WETTZELL will drop out from ~08:15-09:45 on DOY 083 to observe the one-hour UT1 Intensive session. And there will probably be a USNO/VLBA Intensive on DOY 084, in which case PIETOWN, MK-VLBA and maybe SC-VLBA will drop out for ~100 minutes. SOURCE SELECTION ================ There are a total of 79 sources in this session: 60 are from the geodetic source list, 6 are southern sources with few observations to be observed on the HH-HO baseline, and 15 are sources with very few or no previous X/S observations to be observed on the VLBA baselines. SCHEDULING ALGORITHMS ===================== This schedule uses the "SRCEVN SQRT" mode of Sked. In the absence of any constraints, Sked will preferentially observe strong sources that have high visibility. This mode attempts to smooth out the number of observations per source. RECORDING MODE and FREQUENCIES ============================== The data will be recorded using the following setup: 8 channels, each 16 Mhz bandwidth 1:2 fan-out 32 MHz sample rate 2-bit sampling This recording mode is a modified version of 512-16(RDV). S-band frequencies were modified for the RFI situation at HOBART26. There is no correlator speed-up factor. The frequency sequence covers 560 MHz at X-band and 160 MHz at S-band using 4 channels in each band. At the VLBA, the X-band uses two LO's in order to fit into the VLBA 512 MHz passband. At the Mark4 stations, the X-band uses both the high and low parts of the geodetic receivers. Because only 8 channels are available when observing with the VLBA/RDBE/DDC systems, a wider spanned bandwidth is not advisable. The following tables list the setup for the VLBA stations and the geodetic stations with DBBC, Mark IV, Mark 5, and VLBA5 back ends. VLBA | HARTRAO Chan Sky Tracks LO IF BBC | LO IF BBC BBC# 1 X 8365.75 2, 4, 6, 8 7600 B 765.75| 8080.0 A1 285.75 3 2 X 8445.75 10,12,14,16 7600 B 845.75| 8080.0 A1 365.75 4 3 X 8805.75 18,20,22,24 9600 D 794.25| 8080.0 B2 725.75 5 4 X 8925.75 26,28,30,32 9600 D 674.25| 8080.0 B2 845.75 6 5 S 2212.75 3, 5, 7, 9 3100 A 887.25| 2020.0 C1 192.75 9 6 S 2242.75 11,13,15,17 3100 A 857.25| 2020.0 C1 222.75 10 7 S 2282.75 19,21,23,25 3100 A 817.25| 2020.0 C1 262.75 13 8 S 2372.75 27,29,31,33 3100 A 727.25| 2020.0 C1 352.75 14 VLBA | HOBART26 Chan Sky Tracks LO IF BBC | LO IF BBC BBC# 1 X 8365.75 2, 4, 6, 8 7600 B 765.75| 8080.0 A1 285.75 3 2 X 8445.75 10,12,14,16 7600 B 845.75| 8080.0 A1 365.75 4 3 X 8805.75 18,20,22,24 9600 D 794.25| 8080.0 B4 725.75 5 4 X 8925.75 26,28,30,32 9600 D 674.25| 8080.0 B4 845.75 6 5 S 2212.75 3, 5, 7, 9 3100 A 887.25| 2020.0 C2 192.75 9 6 S 2242.75 11,13,15,17 3100 A 857.25| 2020.0 C2 222.75 10 7 S 2282.75 19,21,23,25 3100 A 817.25| 2020.0 D2 262.75 13 8 S 2372.75 27,29,31,33 3100 A 727.25| 2020.0 D2 352.75 14 VLBA | ONSALA60, WETTZELL Chan Sky Tracks LO IF BBC | LO IF BBC BBC# 1 X 8365.75 2, 4, 6, 8 7600 B 765.75| 8080.0 A1 285.75 3 2 X 8445.75 10,12,14,16 7600 B 845.75| 8080.0 A1 365.75 4 3 X 8805.75 18,20,22,24 9600 D 794.25| 8080.0 B1 725.75 5 4 X 8925.75 26,28,30,32 9600 D 674.25| 8080.0 B1 845.75 6 5 S 2212.75 3, 5, 7, 9 3100 A 887.25| 2020.0 C1 192.75 9 6 S 2242.75 11,13,15,17 3100 A 857.25| 2020.0 C1 222.75 10 7 S 2282.75 19,21,23,25 3100 A 817.25| 2020.0 D1 262.75 13 8 S 2372.75 27,29,31,33 3100 A 727.25| 2020.0 D1 352.75 14 VLBA | NYALES13S Chan Sky Tracks LO IF BBC | LO IF BBC BBC# 1 X 8365.75 2, 4, 6, 8 7600 B 765.75| 8080.0 A1 285.75 3 2 X 8445.75 10,12,14,16 7600 B 845.75| 8080.0 A1 365.75 4 3 X 8805.75 18,20,22,24 9600 D 794.25| 8080.0 B1 725.75 5 4 X 8925.75 26,28,30,32 9600 D 674.25| 8080.0 B1 845.75 6 5 S 2212.75 3, 5, 7, 9 3100 A 887.25| 1700.0 C1 512.75 9 6 S 2242.75 11,13,15,17 3100 A 857.25| 1700.0 C1 542.75 10 7 S 2282.75 19,21,23,25 3100 A 817.25| 1700.0 D1 582.75 13 8 S 2372.75 27,29,31,33 3100 A 727.25| 1700.0 D1 672.75 14 VLBA | SESHAN25 Chan Sky Tracks LO IF BBC | LO IF BBC BBC# 1 X 8365.75 2, 4, 6, 8 7600 B 765.75| 8100.0 A 265.75 3 2 X 8445.75 10,12,14,16 7600 B 845.75| 8100.0 A 345.75 4 3 X 8805.75 18,20,22,24 9600 D 794.25| 8100.0 B 705.75 5 4 X 8925.75 26,28,30,32 9600 D 674.25| 8100.0 B 825.75 6 5 S 2212.75 3, 5, 7, 9 3100 A 887.25| 2000.0 C 212.75 9 6 S 2242.75 11,13,15,17 3100 A 857.25| 2000.0 C 242.75 10 7 S 2282.75 19,21,23,25 3100 A 817.25| 2000.0 D 282.75 13 8 S 2372.75 27,29,31,33 3100 A 727.25| 2000.0 D 372.75 14 Special operations for non-VLBA stations: ========================================= All non-VLBA stations: Please note that due to the frequency sequence, phase-cal will not be visible with a 10 kHz viewing filter in the USB channels. If you have another means to verify phase-cal, please use it. If you have a Mark IV Decoder, please contact Ed.Himwich@nasa.gov if you would like advice on how to set it up to check phase-cal for this frequency sequence. Please check the procedures created by drudg. The discussion below represents our best understanding of the station configuration. If you find an error, please correct it and let us know so we can correct the catalog. HARTRAO: This station uses a DBBC rack. BBCs 3 & 4 are used at X-band with IF A, input 1. BBCs 5 & 6 are used at X-band with IF B, input 2. BBCs 9, 10, 13 & 14 are used for S-band with IF C, input 1. HOBART26: This station uses a DBBC rack. BBCs 3 & 4 are used at X-band with IF A, input 1. BBCs 5 & 6 are used at X-band with IF B, input 4. BBCs 9 & 10 are used for S-band with IF C, input 2. BBCs 13 & 14 are used for S-band with IF D, input 2. WETTZELL: This station uses a DBBC rack. BBCs 3 & 4 are used at X-band with IF A, input 1. BBCs 5 & 6 are used at X-band with IF B, input 1. BBCs 9 & 10 are used for S-band with IF C, input 1. BBCs 13 & 14 are used for S-band with IF D, input 1. ONSALA60: This station uses a DBBC rack. BBCs 3 & 4 are used at X-band with IF A, input 1. BBCs 5 & 6 are used at X-band with IF B, input 1. BBCs 9 & 10 are used for S-band with IF C, input 1. BBCs 13 & 14 are used at S-band with IF D, input 1. NYALES13: This station uses a DBBC rack. BBCs 3 & 4 are used at X-band with IF A, input 1. BBCs 5 & 6 are used at X-band with IF B, input 1. BBCs 9 & 10 are used for S-band with IF C, input 1. BBCs 13 & 14 are used at S-band with IF D, input 1. SESHAN25 The logs from SESHAN25 indicate that the station uses a VLBA5 rack, but we are not sure that is correct, please let us know. BBCs 3 & 4 are used at X-band with IF A, input NOR. BBCs 5 & 6 are used at X-band with IF B, input NOR. BBCs 9 & 10 are used for S-band with IF C, input NOR. BBCs 13 & 14 are used at S-band with IF D, input NOR. For Mark IV racks, the IF3 command in the procedure IFDSX assumes that VC3 and VC10 will be patched to High. Please verify that the switches for your IF3 module are wired this way, and if they are not please edit the IF3 command to change the switches. The standard wiring is described in "help=if3". If you have questions about the wiring, please contact Brian Corey at Haystack. If you wish to record back-up channels, please add appropriate instances of bbcxx=..., vcxx=..., valo=..., va=..., vblo=.., and/or vb=... commands to the BBC/VC setup procedure. CHECKLIST for non-VLBA stations =============================== Please follow the checklist below to ensure you have done all the necessary steps for this session: 1. Make .prc file with DRUDG and check them out, or use the procedures from the last RV session. Check out parity check procedures. 2. Make the .snp file with DRUDG. 3. Set up your system to monitor the clocks with the "gps-fmout" or "fmout-gps" commands. If you have questions about this, please contact Ed Himwich as soon as possible. 4. Send a "ready" message an hour or so before the session to the ivs-ops mail list (ivs-ops@lists.nasa.gov). Copy analysts@nrao.edu and vlbiobs@aoc.nrao.edu on your ready message. 5. Send a "start" message soon after you have started recording. Copy analysts@nrao.edu and vlbiobs@aoc.nrao.edu on the message. 6. At the end of the session, send a "finish" message summarizing how the session was conducted. Copy analysts@nrao.edu and vlbiobs@aoc.nrao.edu on your message. 7. Transfer your log file to your normal IVS data center. The directories for the IVS servers are listed below: ftp ivsopar.obspm.fr/ivsincoming ftp ivs.bkg.bund.de/ivsincoming Correlation =========== This session will be correlated at NRAO/VLBA on the VLBA DiFX software correlator. The VLBA correlator can now only read Mark6 modules. The Mark4 stations will need to E-transfer their data to Haystack, where it will be copied onto a Mark6 module and shipped to the VLBA in Socorro, New Mexico. These stations will need to coordinate this with Haystack Observatory (contact: Jason SooHoo at jsoohoo@haystack.mit.edu). The VLBA needs to process this session as soon as possible because of limited media. So please try to set up the E-transfer as soon as possible after the session ends.