RV148 (Astrometric/Geodetic VLBA-148) 2021 JUL 07 18:00 UTC DOY 188 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. RV148 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 7 non-VLBA stations scheduled - HARTRAO, HOBART26, NYALE13S, NYALES20, ONSALA60, SESHAN25 and WETTZELL. HOBART26, SESHAN25 and NYALE13S are new this year to the RV sessions. NYALE13S was tagged along in order to improve the tie with the legacy X/S stations. The 7 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 many antennas near the beginning and 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 Ho Kp La Mk Nl Ny On Ov Pt Sc Sh Wz Ns 0716+714 21188-180000| 319 300 351 302 300 337 331 300 364 310 300 360 357 362 364| 3C274 21188-180725| 300 405 407 406 392 377 416 416| 0215+015 21188-180801| 322 300 300 317 300 321 318 300 322 | 1803+784 21189-173437| 328 341 309 338 338 300 315 300 541 333 338 316 541 319 349| 3C274 21189-174107| 300 340 340 362 348 362 362| 0215+015 21189-174152| 323 317 300 317 318 323 319 317 | 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 45% to 57%, and the average idle time decreases from 24% to 12%. The observing time increases most at the faster antennas and least at the slower antennas. Purpose ======= This is the fourth 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: rv148.skd At the IVS Data Center (ftp://cddisa.gsfc.nasa.gov/vlbi/ivsdata/aux/2021/rv148): Sked file: rv148.skd Text file: rv148.txt At the VLBA/NRAO: Sked file: rv148.skd Vex file: rv148.vex Text file: rv148.txt Summary file: rv148.sksum This session uses the VLBA stations and 7 IVS stations. The IVS stations are: HARTRAO, HOBART26, NYALE13S, NYALES20, ONSALA60, SESHAN25 and WETTZELL. NYALE13S was tagged along. 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 Ny=NYALES20 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 Ny Ns On Ov Pt Sc Sh Wz Avg % obs. time: 57 60 52 57 53 60 61 53 58 62 50 61 59 61 58 45 61 57 % cal. time: 6 6 3 5 3 6 6 5 6 5 4 6 6 6 5 4 6 5 % slew time: 27 27 40 27 31 28 26 28 26 21 2 26 26 27 27 34 13 26 % idle time: 9 7 5 10 11 6 6 13 9 11 43 6 8 6 9 15 19 12 total # scans: 486 497 249 475 275 510 498 454 476 451 323 476 496 507 467 372 485 441 # scans/hour : 20 21 10 20 11 21 21 19 20 19 13 20 21 21 19 16 20 18 Avg scan (sec): 101 104 179 103 168 101 106 101 106 118 135 111 103 103 107 105 109 114 # data tracks: 16 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 16 Total TB(M5): 3.14 3.30 2.85 3.15 2.95 3.31 3.36 2.95 0.00 3.41 2.78 3.38 3.27 3.35 3.20 2.49 3.39 2.96 # OF OBSERVATIONS BY BASELINE | Br Fd Hh Hn Ho Kp La Mk Nl Ny Ns On Ov Pt Sc Sh Wz Total ----------------------------------------------------------------------------------------------- Br| 337 1 309 8 357 370 269 347 179 154 114 384 367 252 78 114 3640 Fd| 5 312 9 444 453 247 357 127 112 92 383 464 325 43 96 3806 Hh| 11 207 4 4 0 10 21 10 35 0 4 22 78 45 457 Hn| 0 290 320 160 401 197 168 161 271 308 369 45 167 3489 Ho| 13 9 36 3 18 4 14 12 11 4 118 19 485 Kp| 445 290 335 127 106 85 429 473 287 52 86 3823 La| 250 369 137 121 99 396 479 314 48 102 3916 Mk| 186 98 80 42 321 271 144 134 33 2561 Nl| 179 156 139 312 354 350 46 142 3686 Ny| 238 315 129 135 134 158 285 2477 Ns| 207 108 115 121 100 186 1986 On| 79 94 135 130 411 2152 Ov| 414 248 67 80 3633 Pt| 302 51 98 3940 Sc| 18 154 3179 Sh| 125 1291 Wz| 2143 Number of 2-station scans: 466 Number of 3-station scans: 278 Number of 4-station scans: 132 Number of 5-station scans: 103 Number of 6-station scans: 96 Number of 7-station scans: 65 Number of 8-station scans: 62 Number of 9-station scans: 76 Number of 10-station scans: 96 Number of 11-station scans: 45 Number of 12-station scans: 32 Number of 13-station scans: 29 Number of 14-station scans: 9 Number of 15-station scans: 9 Number of 16-station scans: 0 Number of 17-station scans: 0 Total number of scans: 1498 Total number of obs: 23332 INTENSIVE BREAKS ================ WETTZELL will drop out from ~18:15-19:45 on DOY 188 to observe the one-hour UT1 Intensive session. And there will probably be a USNO/VLBA Intensive on DOY 189, in which case HN-VLBA and MK-VLBA will drop out for ~90 minutes. SOURCE SELECTION ================ There are a total of 83 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, 15 are prospective ecliptic navigation sources and 2 are requested sources. 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 | NYALES20 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 C1 262.75 13 8 S 2372.75 27,29,31,33 3100 A 727.25| 2020.0 C1 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.