TJAN24

General information

• Fringe test between PV and NOEMA (single antenna) at 3mm
• Done with the EHT setup 4x2GHz dual-pol
• PV with 2-of-4 x R2DBE and 1 x DBBC3; on sky demonstration of DBBC3 GMVA fringes
• PV had poor IF bandpass equalization, and NOEMA had low optical power in parts of Rx LSB
• Fringe SNR drops notably from b1&b2 (good SNR) to b3&4 (low SNR). Same behaviour in e20j23 but with opposite backend assignment at PV rules out backend issues. Haystack is still to correlate e20j23 NOEMA data with rest of Jan 2020 DR stations (except for PV), remains to be seen if a NOEMA issue, or PV.

Fringes

A-list files

Entire 3-scan tjan24 correlated with 2 x 512 MHz zoombands: alist for b1  b2  b3  b4

Entire 3-scan tjan24 correlated with 32 x 64 MHz zoombands: alist for b1  b2  b3  b4

Notes

• Email Bremer (28.1.2020) :

...Wenn ich Olivier richtig  verstanden habe, sollte die Richtung der R2DBE Spektren im LSB invers zu der Himmelsfrequenz laufen (da gab es mal ein Mißverständnis), im USB mit der Himmelsfrequenz, und wir sollten Signal auf 100-1700 MHz haben in dem 0-2048 MHz Band.
LO1  Frequenz war 92.101000 GHz, wir sind also 1 MHz verschoben relativ zu Pico.
Unser 1PPS Signal sollte einen mittleren Null Offset relativ zu GPS haben, ich hoffe, die Zero Crossings werden Euch nicht stören. Drift sollte sehr klein sein, unser Fit gab zero Drift. VLBI antenna war A9, auf Pad Position E03   4523999.442, 468067.530, 4460310.069 (nach Dave Graham's Skript).
Wir waren für alle 3 Scans auf der 5 MHz Referenz der Masers, genau wie für die 1.3 mm Daten. Die Quellen wurden lokal sehr gut detektiert.

• Email Bremer (5.2.2020) :

LSB: B1:Fsky=LO1-7000-IF_R2DBE, B2:Fsky=LO1-5000-IF_R2DBE
B1: in the R2DBE [0, 2048] MHz => on the sky [85101, 83053] MHz
B2: in the R2DBE [0, 2048] MHz => on the sky [87101, 85053] MHz
USB: B3:Fsky=LO1+5000+IF_R2DBE, B4:Fsky=LO1+7000+IF_R2DBE
B3: in the R2DBE [0, 2048] MHz => on the sky [97101, 99149] MHz
B4: in the R2DBE [0, 2048] MHz => on the sky [99101, 101149] MHz

• Gino Tuccari (5.2.2020) :

The 0-2G|2-4G FIRs do not flip the baseband orientation.
The baseband orientation depends on the 4-12G IF, Valon LO tuning, analog filtering.

--tjan24: in practice, oct2-4 is flipped by FIR/shift, oct0-2 is not flipped!
Also seen at Pico with spectral line.

Basebands

• NOEMA signal chain

• Pico calculations

1st LO 92100
B3,B4 : 1st USB : bdc1 5-7|7-9 at 99100M mid : 5-7:97052..99100 | 7-9:99100..101148
B1,B2 : 1st LSB : LO 9.048G lsb : net usb start at 83052M : oct0-2:83052-85100 | 2-4:85100-87148

• PV signal chain

Issues

• Data weights for PV-RR are reduced. On the 4-module set containing "hand-carry" copies of the other 4-set modules, copied modules have 6 out of the 16 fragment files per scan missing. Apparantly the copy procedure was incomplete. Affects bands 1, 3, and 4.