RV132 (Astrometric/Geodetic VLBA-132) 2018 NOV 14 18:00 DOY 318 Notes prepared by David Gordon, Ed Himwich and John Gipson NVI/GSFC Special notes for this experiment ================================= This session will use the RDBE/DDC/Mark5C 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 now span 560 MHz. The S-band frequencies are being shifted up by 8 MHz from the last few RV's to try to avoid RFI in the third S-band channel (2352.75-2360.75 MHZ) at five VLBA stations. The S-band frquencies for this session will be: 2240.75, 2270.75, 2360.75 and 2380.75 MHz. 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. This session will record 8 8-MHz bandwidth channels using 2-bit sampling, as in previous RDV's. The bit rate will be 256 Mbits/sec. The data will be correlated at the VLBA using the VLBA DiFX software correlator. There are 4 non-VLBA stations scheduled - HARTRAO, NYALES20, ONSALA60 and WETTZELL. These 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 Ny On Ov Pt Sc Wz 0955+476 18318-180000| 326 338 300 338 335 343 333 300 324 335 336 343| 2008-159 18318-180714| 300 383 352 372 383| 0955+476 18319-174008| 305 300 300 300 300 305 304 314 331 300 300 331| 2008-159 18319-174728| 355 434 413 434 433| We are again using the new '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 increased from 53% to 64%, and the average idle time decreased from 21% to 10%. The observing time increases most at the faster antennas and least at the slower antennas. Purpose ======= This is the sixth of six coordinated astrometric/geodetic sessions in 2018 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 experiments are being coordinated by the geodetic/astrometric VLBI programs of USNO, NASA, and NRAO. The experiments have been designed so that the same data set may be used by each agency for its particular goals. USNO and Bordeaux Observatory will perform imaging and correction for source structure. These sources will establish a set of core reference sources with known structure and precisely known positions. These data will provide the basis for evaluating the long term stability of the radio reference frame and the ultimate accuracy of wide angle astrometric measurements of extragalactic radio sources using VLBI. NASA and USNO will analyze this data to determine and maintain high accuracy terrestrial reference and celestial reference frames. The data will incorporate the VLBA stations into the VLBI reference frame through the inclusion of other geodetic stations for which we have long histories. This data will also produce highly accurate Earth orientation results and possibly the best nutation results ever produced. NASA and NRAO will use these sessions to provide a service to users who require high quality positions for a small number of sources. While the quality of these results will be high, the observing and data reduction overhead required will be minimal because a small number of such sources can be incorporated into a session of the regular geodetic observations, instead of requiring special observations. Sources for this series of experiments will be selected using the proposed approach. For each experiment we will select a set of ~60 sources from the pool of geodetic, astrometric, and monitoring sources. About 20-30 of these will remain the same from experiment to experiment and will be chosen to optimize the goals of the three groups. A number of poorly observed and/or new requested sources will also be included to obtain or improve their positions. Schedule information ==================== This is a new schedule generated by David Gordon at GSFC using sked. Schedule file name: rv132.skd At the IVS Data Center (ftp://cddisa.gsfc.nasa.gov/vlbi/ivsdata/aux/2018/rv132): Sked file: rv132.skd Text file: rv132.txt At the NRAO/VLBA: VLBA Pointing files: rv132crd.br rv132crd.fd rv132crd.hn rv132crd.kp rv132crd.la rv132crd.mk rv132crd.nl rv132crd.ov rv132crd.pt rv132crd.sc Summary file: rv132.sksum Sked file: rv132.skd Text file: rv132.txt Vex file: rv132.vex This experiment uses the 10 VLBA stations and 4 IVS stations. The IVS stations are: HARTRAO, NYALES20, ONSALA60 and WETTZELL. Below is the sked summary. Key: Br=BR-VLBA Fd=FD-VLBA Hh=HARTRAO Hn=HN-VLBA Kp=KP-VLBA La=LA-VLBA Mk=MK-VLBA Nl=NL-VLBA Ny=NYALES20 On=ONSALA60 Ov=OV-VLBA Pt=PIETOWN Sc=SC-VLBA Wz=WETTZELL Br Fd Hh Hn Kp La Mk Nl Ny On Ov Pt Sc Wz Avg % obs. time: 63 64 61 66 63 64 53 64 70 65 63 64 63 70 64 % cal. time: 5 5 2 4 5 5 4 5 3 3 5 5 4 3 4 % slew time: 25 25 28 23 25 25 22 24 14 12 24 24 22 8 22 % idle time: 7 5 8 6 5 5 19 6 12 19 7 5 11 17 10 total # scans: 436 456 194 376 462 456 366 428 292 225 445 453 344 286 372 # scans/hour : 18 19 8 16 19 19 15 18 12 9 19 19 14 12 16 Avg scan (sec): 124 121 271 151 119 121 126 130 206 249 122 123 157 212 158 # data tracks: 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 Total TB(M5): 1.73 1.76 1.68 1.81 1.75 1.76 1.47 1.78 1.92 0.00 0.00 0.00 0.00 0.00 1.12 # OF OBSERVATIONS BY BASELINE | Br Fd Hh Hn Kp La Mk Nl Ny On Ov Pt Sc Wz Total -------------------------------------------------------------------------------- Br| 328 12 228 331 341 284 303 125 40 347 338 186 52 2915 Fd| 22 241 423 438 283 362 85 28 373 439 235 37 3294 Hh| 63 13 21 0 35 112 154 5 18 71 177 703 Hn| 218 240 132 291 141 77 190 234 283 110 2448 Kp| 419 318 338 73 22 411 428 213 23 3230 La| 283 363 84 30 375 444 234 37 3309 Mk| 214 59 16 336 284 126 18 2353 Nl| 115 43 303 356 265 62 3050 Ny| 127 73 81 97 189 1361 On| 22 29 67 180 835 Ov| 381 182 23 3021 Pt| 229 33 3294 Sc| 94 2282 Wz| 1035 Number of 2-station scans: 1 Number of 3-station scans: 235 Number of 4-station scans: 109 Number of 5-station scans: 52 Number of 6-station scans: 60 Number of 7-station scans: 97 Number of 8-station scans: 94 Number of 9-station scans: 69 Number of 10-station scans: 95 Number of 11-station scans: 29 Number of 12-station scans: 8 Number of 13-station scans: 3 Number of 14-station scans: 0 Total number of scans: 852 Total number of obs: 16565 INTENSIVE BREAKS ================ There is an IVS INT01 Intensive session scheduled during RV132. Wettzell will drop out from ~18:15 - 19:45 on DOY 318 for this Intensive. There will also be a USNO/NRAO UT1 Intensive session, scheduled to start at ~06:30 UTC (+/- 4 hrs) on DOY 319, using Pietown and MK-VLBA, so these stations will drop out for about 100 minutes. The exact time is not fixed, so it is not scheduled in, but the loss of these two antennas for a short period should have only a minimal effect. SOURCE SELECTION ================ There are a total of 80 sources scheduled in this session. Among them, 60 are from the geodetic source list, and 20 are sources with few or no previous observions in IVS sessions. 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 1:2 fan-out 16 MHz sample rate 2-bit sampling This recording mode is designated 256-8(RDV). There is no correlator speed-up factor. The frequency sequence covers 560 MHz at X-band and 140 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 2240.75 3, 5, 7, 9 3100 A 859.25| 2020.0 C1 220.75 9 6 S 2270.75 11,13,15,17 3100 A 829.25| 2020.0 C1 250.75 10 7 S 2360.75 19,21,23,25 3100 A 739.25| 2020.0 C1 340.75 13 8 S 2380.75 27,29,31,33 3100 A 719.25| 2020.0 C1 360.75 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 1N 285.75 3 2 X 8445.75 10,12,14,16 7600 B 845.75| 8080.0 1N 365.75 4 3 X 8805.75 18,20,22,24 9600 D 794.25| 8580.1 3N 225.65 5 4 X 8925.75 26,28,30,32 9600 D 674.25| 8580.1 3N 345.65 6 5 S 2240.75 3, 5, 7, 9 3100 A 859.25| 2020.0 2N 220.75 9 6 S 2270.75 11,13,15,17 3100 A 829.25| 2020.0 2N 250.75 10 7 S 2360.75 19,21,23,25 3100 A 739.25| 2020.0 2N 340.75 13 8 S 2380.75 27,29,31,33 3100 A 719.25| 2020.0 2N 360.75 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 2240.75 3, 5, 7, 9 3100 A 859.25| 2020.0 C1 220.75 9 6 S 2270.75 11,13,15,17 3100 A 829.25| 2020.0 C1 250.75 10 7 S 2360.75 19,21,23,25 3100 A 739.25| 2020.0 D1 340.75 13 8 S 2380.75 27,29,31,33 3100 A 719.25| 2020.0 D1 360.75 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. HARTRAO: This station uses a DBBC rack. Please use the procedures generated by DRUDG. 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. NYALES20 and WETTZELL: These stations have Mark IV or Mark 5 racks. Please use the procedures generated by DRUDG. VCs 3 & 4 are used at X-band with IF 1. VCs 5 & 6 are used at X-band with IF 3. VCs 9, 10, 13 & 14 are used at S-band with IF 2. ONSALA60: This station uses a DBBC rack. Please use the procedures generated by DRUDG. 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. 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 valo=..., va=... vblo=... and vb=... commands in the VCSX8 procedure. CHECKLIST for non-VLBA stations =============================== Please follow the checklist below to ensure you have done all the necessary steps for this experiment: 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 experiment to the ivs-ops mail list. Copy analysts@nrao.edu on your ready message. 5. Send a "start" message soon after you have started recording. Copy analysts@nrao.edu on the message. 6. At the end of the experiment, send a "finish" message summarizing how the experiment was conducted. Copy analysts@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 cddisin.gsfc.nasa.gov/ivsincoming ftp ivsopar.obspm.fr/ivsincoming ftp ivs.bkg.bund.de/ivsincoming Correlation =========== This experiment will be correlated at the NRAO/VLBA on the VLBA DiFX software correlator. Most of the Mark4 stations are now E-transfering their data to Haystack, where it will be copied 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 the session at their correlator 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. If you need to ship the media instead, please ship it to Socorro as soon after the experiment as is practical. It should be shipped to the following address: Socorro address for media shipping: VLBA Array Operations Center National Radio Astronomy Observatory Attn: Juan Cordova 1003 Lopezville Road Socorro, NM 87801 U.S.A. Phone: 575-835-7000 Shipping and VLBA contact information is also given at: https://science.nrao.edu/facilities/vlba/contact/shipping_information. Please use one of the recommended shipping companies (FedEx, UPS, DHL, TNT). Please ship your media to the VLBA the same day the session ends or the next business day (just like the R1/R4 media is shipped). If you know that there is going to be a problem sending your media to the VLBA the same day the session ends or the next business day, please let us (David.Gordon-1@nasa.gov) know as soon as possible so that we, along with the VLBA, can determine the best course of action. If you have any questions or comments, please let us know.