Future LBO Developments Steven Durand Jonathan Romney 1

Future LBO Developments Steven Durand & Jonathan Romney 1 Insert Date-Meeting Name

2 Insert Date-Meeting Name US-China workshop July 2017

Samplers in the Vertex room 3 Insert Date-Meeting Name US-China workshop July 2017

RF over Fiber 4 Insert Date-Meeting Name US-China workshop July 2017

Attributes of RF over Fiber 5 Positive Negative • Only Analog hardware is in the antenna • Samplers in the control building are easier to cool • Bandwidth is determined by Fiber and RF over Fiber equipment • LO signals are required in the vertex room. • Analog and LO Fiber wraps require effort • Bandwidth is determined by Fiber and RF-over-Fiber equipment Insert Date-Meeting Name US-China workshop July 2017

Samplers in the Vertex room 6 Insert Date-Meeting Name US-China workshop July 2017

Attributes of Vertex Room Samplers Positive 7 Negative • LO signals are • Samplers are close to required in the vertex the receivers - less room. noise • LO Fiber wraps • Bandwidth is require effort determined by • Samplers in the samplers vertex room can • Digital fiber wraps generate RFI easier • Many digital fiber • Possible to have transmitters multiple colors on a • Cooling Digital single fiber Electronics in the • NRAO is familiar with Insert Date-Meeting Name US-China workshop July 2017 is required Vertex this technique.

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MARK 6 • Four 10 Gig. E input ports • 16 Gbps sustained record capability • Supports up to four 8 -disk modules for recording/playback • Based on high-performance COTS hardware • Easily upgradeable hardware on Moore's Law curve • Linux OS (6. 0. 3) • Supports all VLBI data formats 9 Insert Date-Meeting Name US-China workshop July 2017

Data Transmission to the Correlator • Mark 6 disk recorders for the VLBA. We are installing units at one VLBA site. • A corresponding complement of Mark 6 unit to replay the recorded bits into the correlator • We are also investigating a real-time data transmission scheme, using long-range optical fiber networks 10 Insert Date-Meeting Name US-China workshop July 2017

VLBA X/Ka Band Dichroic Ka-band 26. 5 to 40. 0 GHz X-band 7. 9 to 8. 9 GHz Maintaining the existing S/X system 11 Insert Date-Meeting Name US-China workshop July 2017

Weather Station Specification (VLBA) • • • 12 Wind Direction : 0 -360 ± 3° Wind speed: 0 -60 m/s ± 5% Barometer: 600 -1000 mbar ± 6 mbar Temperature: -40 to 60°C ± 0. 4°C Dew Point: -45 to 50°C ± 1°C Solar Irradiance: 0 - 1400 W/m 2 ± 3 W/m 2 Liquid precipitation: resolution 0. 001 inches ± 5% Camera (360º Sky View) Battery back-up Calibration required – annually Insert Date-Meeting Name US-China workshop July 2017

Monitor and Control System • Instrumentation installed at VLBA stations, as part of the 2013 upgrade, required new monitor-and-control capabilities, Monitor Interface Board (MIB) were installed by adapting the EVLA’s Ethernet based system. • VLBA-oriented “executor” program was developed, to support the new MIBs and has already replaced many functions of the original VLBA monitor-andcontrol system. • All the features with the MIB based system are available, search engine, plotting, and archiving 13 Insert Date-Meeting Name US-China workshop July 2017

VLBA ACU/Servo Upgrade – Replaces the functionality of current ACU and FRM electronics – COTS PC-104+ based CPU board stack running Real Time Linux – Ethernet interfaces to both VLBA M&C system & a dedicated Maintenance/ Engineering GUI (Linux based PC) – Fully in-house supportable software system • We have all source code and rights to modify it for our use – Fully compatible with the New VLBA Monitor & Control system • Appears to the system as another MIB 14 – Additional built-in test, evaluation and engineering capability using the supplied GUI Insert Date-Meeting Name US-China workshop July 2017 – Supports all current safety requirements

Water-Vapor Radiometers • Many VLBA observations require accurate corrections for fluctuations in interferometer phase and delay • The prototype NRAO Water-vapor radiometer (WVR) is designed to make simultaneous measurements of the water-vapor content using the 22 -GHz emission lines of H 2 O molecules. • Successfully demonstrated a 3 -channel WVR system • An improved 5 -channel design is being developed 15 Insert Date-Meeting Name US-China workshop July 2017

Interconnection of three Helium Compressors 16 Insert Date-Meeting Name US-China workshop July 2017

RFI Generator 17 Insert Date-Meeting Name US-China workshop July 2017

RFI shielded Rack • 60 -80 d. B of shielding. 2 – 20 GHz • Honey comb air filters • Cooling air flow Bottom to Top • RFI absorbing foam lined • AC power filters • Filtered data connectors • RFI tight fiber connectors 18 Insert Date-Meeting Name US-China workshop July 2017

Equipto Rack RF Shielding 19 Insert Date-Meeting Name US-China workshop July 2017

RFI tight Modules Moto: Too many screws >60 d. B of shielding from 0. 2 – 18 GHz Many styles: double wide, Triple wide, with heat sink, 20 Honey comb filters or wave guides enable forced air cooling. Insert Date-Meeting Name US-China workshop July 2017

Module RF Shielding 60 d. B 18 GHz I 21 Insert Date-Meeting Name US-China workshop July 2017

Working to Reduce the RFI • Module plus Rack > 120 d. B of shielding • Sometimes challenging to retrofit commercial enclosures • Best to design using RFI tight enclosures at start – – 22 Consider cooling AC power filters Fiber connections Filtered data connectors Insert Date-Meeting Name US-China workshop July 2017

Conclusion • Existing suite of hardware is mature yet still scientifically interesting • LBO has well-designed enhancement projects ready to install – – – 2 Gbit samplers Mark 6 recording X/Ka receiver system Upgraded Weather station Replacement ACUs • Compatibility - Data rates, Tunability, Channel band passes • LBO is interested in data quality and system compatibility 23 Insert Date-Meeting Name US-China workshop July 2017

Shanghai SOHM-4 A Maser 24 Insert Date-Meeting Name US-China workshop July 2017

www. lbo. us The Long Baseline Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. 25 Insert Date-Meeting Name US-China workshop July 2017