OSO 20m Tri-Band Receiver Project
Abstract
A new Tri-band receiver would advantageously replace Onsala's 20m telescope existing millimeter wave single-pixel receivers within the K,Q and W frequency bands, having next-generation performance, IF bandwidth, and sampling capabilities. The receiver system will support both Astro VLBI observations and single-dish functionality. Moreover, the new receiver aims to enable simultaneous observations over those frequency bands, compatible with current and coming Tri-band receivers within the EVN (following on from Korean VLBI Network (KVN) developments) At the workshop, we present the main specifications, the conceptual design and overview of the project plan for a future Tri-band receiver for Onsala's 20 m telescope.
Full text
OSO 20m Tri-Band Receiver Project Leif Helldner*, Magnus Dahlgren** Denis Meledin*, Mugundhan Vijayaraghavan** Onsala Space Observatory John Conway, Vincent Desmaris*, Michael Lindqvist, Roger Hammargren**, Jun Yang, Henrik Olofsson *GARD: Max Behrens, Victor Belitsky, Mathias Fredrixon, Sven-Erik Ferm, François Joint. Igor Lapkin, Avan Mirkhan, Alexey Pavolotsky, Magnus Strandberg, Erik Sundin **TSG: Rolf Ahlman, Simon Casey, Lars Eriksson, Jan Karaskuru, Magnus Kjerling, Peter Hillerström, Rebekka Handdirk, Mikael Lerner, Johannes Reldin IVTW 2025 [email protected] [email protected]
2025-10-24 Background / Motivation •Multi-frequency receivers with shared optical path, using frequency phase transfer have a long history within Geodetic VLBI (S/X) and have lately become an advantage for Astro VLBI •Using Three-bands was initiated and developed by Korean VLBI network (KVN) operating six telescopes at 22/43/86 GHz simultaneously. They was soon followed by other stations developing multi-band receivers, like Yebes, Nobeyama, INAF, TNRT, MPIfR & Metsahovi •In 2020 European VLBI Network (EVN) developed a scientific roadmap for VLBI in the next decade. This roadmap propose EVN stations with appropriate dish frequency capabilities to develop and deploy two types of new receivers: Broad band receiver for C/X (4.5-9 GHZ) and Tri-band receivers to cover 22/43/86 GHz •2019-2022 OSO start initial work on broad band receivers and frequency selective surfaces •In 2024 OSO initiated to form a Tri-band project organisation to develop a proposal which could lead to a Tri-band receiver for the OSO 20 m antenna, i.e. IF we got funding… 2
2025-10-24 Project objective Directive to start detailed project plan 2024-02-09, with goal to have project start late September or early October 2024. •Result: Replace existing K, Q and W-band single pixel receivers with a new TriBand receiver system in operation @ OSO 20 m antenna •Time: Within 30 months from project start •Limitations: Excluding phase calibration generator & measurement equipment Project plan finished and presented December 2024 – Project paused! 2025 - Funding applications was sent out… 3
2025-10-24 AI help: What is a Tri-band receiver what does such device look like? ”Create a graphic which show a radio camera with a grey beam coming in, then the red light beeing separated off by reflecting from a first dichroic mirror which is transmitting green-blue, which then is separated into green and blue beams by a second dichroic miror. Add something for scale, like a human figure by the side of the camera” 4
2025-10-24 AI help: What is a Tri-band receiver what does such device look like? ”Create a graphic which show a radio camera with a grey beam coming in, then the red light beeing separated off by reflecting from a first dichroic mirror which is transmitting green-blue, which then is separated into green and blue beams by a second dichroic miror. Add something for scale, like a human figure by the side of the camera” 5
2025-10-24 AI help: What is a Tri-band receiver what does such device look like? ”Create a graphic which show a radio camera with a grey beam coming in, then the red light beeing separated off by reflecting from a first dichroic mirror which is transmitting green-blue, which then is separated into green and blue beams by a second dichroic miror. Add something for scale, like a human figure by the side of the camera” 6
2025-10-24 AI help: What is a Tri-band receiver what does such device look like? ”Create a graphic which show a radio camera with a grey beam coming in, then the red light beeing separated off by reflecting from a first dichroic mirror which is transmitting green-blue, which then is separated into green and blue beams by a second dichroic miror. Add something for scale, like a human figure by the side of the camera” 7
2025-10-24 AI help: What is a Tri-band receiver what does such device look like? ”Create a graphic which show a radio camera with a grey beam coming in, then the red light beeing separated off by reflecting from a first dichroic mirror which is transmitting green-blue, which then is separated into green and blue beams by a second dichroic miror. Add something for scale, like a human figure by the side of the camera” 8
2025-10-24 Funding secured! Grant application approved • Hasselblad foundation contribution Full funding Includes 1 FTE x 2 years • Onsala Space Observatory’s contribution Project management GARD - 1,5 FTE x 3 years TSG - 2 FTE x 3 years Receiver commisioning 9 Charles ”Pete” Conrad / NASA
2025-10-24 Onsala Technical Support Group, TSG 16
2025-10-24 Technical solution Down-conversion 17 • Wideband down-conversion to 16 GHz IF frequency for Q&W • IQ-mixers combined with IF hybrids to achieve sideband suppression • A single synthesizer provides fundamental LO for K and uses multipliers for Q and W • Down-converters for Q and K build with commercial building blocks • Down-conversion for W may be build by an external company
2025-10-24 Technical solution IF-transport 18 • IF signal transported to Backend in control room • W-band and Q-band will use four 0-16 GHz RFOF links • K-band uses two ”low” cost 0-6 GHz RFOF link
2025-10-24 Technical solution IF distribution and Backend 19 • DBBC3 Used as backend • 8 to 4 IF Switch to support various frontends • IF selector switch allowing selection of baseband or down converted input to backend. • Will support a large variety of configurations. E.g. W-band 16 GHz or 4 GHz for K and Q-band and 8 GHz for Wband.
2025-10-24 Technical solution 8 to 4 IF switch 20 • Any four output combinations out of 8 inputs • Solid state switches, 0-18 GHz BW
2025-10-24 Technical solution Software 21 • Low-level software for commanding and reading out data (ASCII-based TCP/IP) E.g. frequency set-up, mixer set-up, mirror positions, KOS control, PLM control, IF-switches, cryo control and environmental sensors • Distribution of data (via "shamecasts") -> logging and monitoring displays • Watchdog and alarm system • Integration into BIFROST observing system • Modifications to local FS (Field System) code controlling VLBI observations
2025-10-24 22 QUESTIONS? We reach out to you for: * *not restricted to Tri-band or VLBI activities only •Engineer for a two year project employment •Panel experts during technical review’s •R&D collaborative partners •RFQ’s for the best possible components •Exchanging ideas and experiences •Unifying Tri-band specifications & requirements IVTW 2025 [email protected] [email protected]