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Italian VLBI Experiments - results and challenges to be tackled

Matteo Stagni - IVTW 2016 Haystack - 12 October 2016

Italian VLBI recapSTATIONS Dish Backend Formatter Recorder Network

Link

Medicina 32 mt dBBC Fila10G Mark5C 10 Gbit

Noto 32 mt dBBCFila10G

+ Mark5B

Mark5B 10 Gbit

SRT 64 mt dBBCFila10G

+ Mark5B

Mark5B +

Mark5C-

Matera(ASI) 20 mt VLBA Mark5B Mark5B 500 Mbit

Cluster view

Infiniband 40Gbit connection

10 Gbit network

16 cores each

24 disks bay

Now 150 TB available (20 TB SATA + 30 TB SAS each)

Now purchasing a new node

VLBI - IT astro

• Data from most station (Sr - Mc - Nt - Ys - On) is now VDIF coming from DBBC backend

• SCHED/SKED need workarounds for this - Maybe VEX2 is the answer?

• At the moment correlator side manual hacks kick in

VLBI - IT astro*================================================== * DEFINITION OF VDIF TRACK BLOCK USING DIFX *================================================== $TRACKS def VDIF; track_frame_format = VDIF/8032/2; enddef;

*================================================== * DEFINITION OF VDIF THREAD BLOCK USING SFXC *================================================== $THREADS; *** single-thread set-up *** FORMAT: last field = total bit-rate over all threads *** THREAD: thrd.ID : backend # : recorder # : data-rate of thread : N_chan : N_bit : : : bytes/packet ; def VDIF512; format = VDIF : : 512;thread= 0:1:1:512:16:2:::8000; channel = &CH01 : 0 : 8;channel = &CH02 : 0 : 12;channel = &CH03 : 0 : 0;channel = &CH04 : 0 : 4;channel = &CH05 : 0 : 9;channel = &CH06 : 0 : 13;channel = &CH07 : 0 : 1;channel = &CH08 : 0 : 5;channel = &CH09 : 0 : 10;channel = &CH10 : 0 : 14;channel = &CH11 : 0 : 2;channel = &CH12 : 0 : 6;channel = &CH13 : 0 : 11;channel = &CH14 : 0 : 15;channel = &CH15 : 0 : 3;channel = &CH16 : 0 : 7;

DiFX SFXC

DiFX also needs re-arranging of $FREQ block

VLBI - IT astroASTRO VDIF ASTRO2 VDIF ASTRO3 VDIF GEO VDIF

CH Sideband BBC Pol CH Sideband BBC Pol CH Sideband BBC Pol CH Sideband BBC Pol

1 U BBC1 R 1 U BBC1 R 1 U BBC1 R 1 U BBC1 R




5 U BBC5 L 5 U BBC9 L 5 U BBC9 L 5 U BBC5 R




9 L BBC1 R 9 L BBC1 R 9 L BBC1 R 9 L BBC1 R

10 L BBC2 R 10 L BBC2 R 10 L BBC3 R 10 L BBC8 R

11 L BBC3 R 11 L BBC3 R 11 L BBC5 R 11 U BBC9 R

12 L BBC4 R 12 L BBC4 R 12 L BBC7 R 12 U BBC10 R

13 L BBC5 L 13 L BBC9 L 13 L BBC9 L 13 U BBC11 R




Table 2: Channels, BBCs, Sidebands and Polarization assignments when using the several ASTRO and the GEO setups on a DBBC when

VDIF data format is selected

12

See M.Stagni publication (memo) https://www.ira.inaf.it/Library/rapp-int/495-16.pdf

https://www.ira.inaf.it/Library/rapp-int/495-16.pdf

VLBI - IT astro

+Torun (Poland) Yebes (Spain)

Irbene (Latvia) Onsala (Sweden)

HartRAO (South Africa)

VLBI - IT data

• Yebes - Onsala - SRT transfer data through m5copy*

• Torun - Hart - Irbene through FTP

* thanks to Harro Verkouter

SCHED VEX

FieldSystem

correlator (DiFX)

dBBC Fila10G (formatter) VSMScheduler+ jive5ab

Scan files

network

MK5B

MK5C MK6Mark5B as formatter

VLBI - IT dataMedicina

+ Noto

standard procedure

Configuring jive5ab on telnet port 2620 in Fila10G Mark5B mode telnet: connect to address 127.0.0.1: Trying 127.0.0.1... Configuration done!

You are scheduling the following scans for experiment ij15l :

Scan ij15l_mc_no0001 @ 2015-02-19 13:00:00 Scan ij15l_mc_no0002 @ 2015-02-19 13:01:15 Scan ij15l_mc_no0003 @ 2015-02-19 13:02:30 Scan ij15l_mc_no0004 @ 2015-02-19 13:03:45 Scan ij15l_mc_no0005 @ 2015-02-19 13:14:00 Scan ij15l_mc_no0006 @ 2015-02-19 13:28:00 Scan ij15l_mc_no0007 @ 2015-02-19 13:29:15 Scan ij15l_mc_no0008 @ 2015-02-19 13:30:30 Scan ij15l_mc_no0009 @ 2015-02-19 13:31:45 Scan ij15l_mc_no0010 @ 2015-02-19 13:42:00 Scan ij15l_mc_no0011 @ 2015-02-19 13:56:00 Scan ij15l_mc_no0012 @ 2015-02-19 13:57:15 Scan ij15l_mc_no0013 @ 2015-02-19 13:58:30 Scan ij15l_mc_no0014 @ 2015-02-19 13:59:45 Scan ij15l_mc_no0015 @ 2015-02-19 14:10:00 Scan ij15l_mc_no0016 @ 2015-02-19 14:24:00 Scan ij15l_mc_no0017 @ 2015-02-19 14:25:15 Scan ij15l_mc_no0018 @ 2015-02-19 14:26:30 Scan ij15l_mc_no0019 @ 2015-02-19 14:27:45 Scan ij15l_mc_no0020 @ 2015-02-19 14:38:00

Waiting for start time ... first scan should begin recording at 2015-02-19 13:00:00

VSMScheduler

VLBI - IT data

• Yebes - Onsala - SRT transfer data through m5copy*

• Torun - Hart through FTP

* thanks to Harro Verkouter

VLBI - IT stats• ~ 20 experiments since January 2016

• 50% of VLBI-IT experiments in 2016 gone wrong

• Receivers problems at the stations - sometimes

• Most of all is setups gone wrong because of manual overrides at the backend or misunderstanding in software correlation.

CYGX3 Experiment

Coverage is continuous from a few up to ~150 Mega-wavelengths, which is important for image fidelity. The source is at about 40 degrees elevation (at lower elevation, the coverage would be a bit 'flatter').

Plot file version 1 created 21-SEP-2016 09:19:45V vs U for CYGX3.SPLIT.2 Source:CYGX3Ants * - * Stokes RRLL IF# 1 Chan# 1

Meg

a W

avln

gth

Mega Wavlngth150 100 50 0 -50 -100 -150

150

100

50

0

-50

-100

-150

CYGX3 ExperimentCalibrated visibility phase (top panels) and amplitudes (bottom panels) versus frequency for a scan on the phase reference source J2007+4029, for baselines to Sardinia. The phases are very stable, and the amplitudes are also reasonably consistent among IFs. The baseline to Ys is more noisy - we are investigating about the reason.

(I)1

550450350250150

2 3 4 5 6 7 8

200

-200

Plot file version 1 created 21-SEP-2016 09:26:33J2007+4029 I6245.UVDATA.1Freq = 22.1715 GHz, Bw = 16.000 MH Calibrated with CL # 8 and BP # 1 (BP mode 1)

Lower frame: Milli Ampl Jy Top frame: Phas degVector averaged cross-power spectrum Several baselines displayed

MC - SR 1 - 3

(I)1 2 3 4 5 6 7 8

NT - SR 2 - 3

(I)1

10 30

550450350250150

2

10 30

3

10 30

4

Channels10 30

5

10 30

6

10 30

7

10 30

8

10 30

200

-200SR - TR 3 - 4

(I)1

10 30

2

10 30

3

10 30

4

Channels10 30

5

10 30

6

10 30

7

10 30

8

10 30

SR - YS 3 - 5

CYGX3 ExperimentThe cleaned and restored image of the phase calibrator, which shows a clear extension to the west (a core-jet structure). While this is not ideal for calibration (the 'ideal' calibrator should be point-like), it is still good enough for its purpose, and it shows clearly that the adopted uv-coverage is able to image also extended features. The noise level is 1.2 mJy/beam and the beam size is 1.3 x 0.9 mas, in position angle -84degrees

BOTH: J2007+40 IPOL 22235.365 MHz J2007+4029.ICLN.1PLot file version 1 created 21-SEP-2016 09:30:06

Grey scale flux range= -5.4 366.5 MilliJY/BEAMCont peak flux = 3.6648E-01 JY/BEAMLevs = 3.753E-03 * (-1, 1, 2, 4, 8, 16, 32)

0 100 200 300

Decl

inat

ion

(J20

00)

Right Ascension (J2000)20 07 44.9456 44.945244.945044.944844.944644.944444.944244.9440

40 29 48.614

48.612

48.610

48.608

48.606

48.604

48.602

48.600

48.598

48.596

48.594

Italian Link for Time and Frequency (LIFT)

• 642 Km from INRIM (Turin) to UNIFI (Firenze) through Medicina station

• double round trip on a single fiber

High-accuracy coherent optical frequency transfer over a doubled 642-km fiber link, D.Calonico et al., Applied Physics B

• Matera will be the next station to be connected

• Plans to connect also Noto and Cagliari

Italian Link for Time and Frequency (LIFT)

Planned

MediLIFT Experiment

• 24 hours Geodetic Experiment

• Medicina set permanently on LIFT clock

• Baseline Medicina - Noto

• VDIF recording in real time

MediLIFT Experiment

Clock jumps

17:30 UTC11:10 UTC

MediLIFT Experiment

A first SOLVE automatic analysis

produced a solution

containing data from

17:30 UTC to 11:10 UTC

MediLIFT ExperimentX-band of the session $16SEP27XI; MEDICINA:NOTO (ambig. spacing: 100.0 [ns])

Time (UTC); 2016 Sep 27

Res:

GR

dela

y,

ns

0

0.1

0.2

0.3

-0.1

-0.2

-0.3

-0.4

2016 Sep 28 06:0018:00

A second more detailed

analysis, where 2 clock brakes were placed, has produced results for the

whole series of data but the

error has increased on the baseline

MediLIFT Experiment

Beginning of experiment

S/X Single Band delay 0

MediLIFT Experiment

End of experiment

S/X Single Band delay 2 µsec

EUR137 INRIM clock @ Medicina

Solutions ok for a few hours

Re-syncs form Turin

Alternate scan clocks 50% local maser 50 % LIFT clock

MediLIFT Experiment

• Was MediLIFT successful? Getting better…

• Need to investigate -> more experiments to follow

• Need to investigate also WhiteRabbit technology (less expensive)

• Funding in progress to connect Matera antenna

One more thing…

100Gbit

40Gbit

10Gbit IRA Bologna

Questions - comments?

Matteo Stagni - IVTW 2016 Haystack - 12 October 2016

Italian VLBI Experiments - results and challenges to … › workshop › ivtw2016 › ...Italian VLBI Experiments - results and challenges to be tackled Matteo Stagni - IVTW 2016

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