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Metsähovi Radio Observatory's major upgrade of the 14-metre radio telescope culminates in 2026: the upcoming new receiver, the world's broadest-band astronomical receiver, is the most significant upgrade to Metsähovi's equipment in decades. The receiver is called 3BR, or Triple-Band Receiver.

The new receiver will replace all five of Metsähovi's current receivers. It covers twice as broad a frequency range as the current five receivers combined and operates on three completely separate frequency bands simultaneously. In addition to entirely new multi-frequency observation capabilities, the new receiver will also upgrade existing observation programmes: for example, in monitoring active galaxies, sensitivity is expected to increase approximately tenfold whilst a single measurement will observe the target at multiple frequencies.

The receiver has been under construction at the in Germany since summer 2024. It will arrive at Metsähovi in autumn 2026, after which the actual commissioning and testing begins, which will take considerable time. On this page, you can follow the 3BR receiver construction process.

A long journey

Years of work are required before the receiver can be taken into use.

2016–2017 - Planning begins for the new receiver

The current six receivers at Metsähovi Radio Observatory are functional for existing purposes, but their limitations are being reached. Some of the technology is outdated, preventing the observatory from achieving the sensitivity levels possible with a high-quality dish antenna. Additionally, switching between frequencies requires changing the entire receiver, which involves days of preparation and interrupts observations for several hours. Researchers and engineers are now exploring available options to determine which solutions best fit Metsähovi’s needs and capabilities.

2018 - Multiple Frequencies at Once

At an radio-astronomical conference, a prototype sparks interest: a new receiver concept has been developed in Korea where the capabilities of three separate receivers can be accommodated in a single receiver. At Metsähovi, the decision is made to investigate this possibility more thoroughly. Discussions with the prototype manufacturers and other collaborating observatories commence.

2019 - Securing Funding Begins

Specification of the new receiver—surveying its characteristics—begins to better determine the device's details and manufacturer. The price is not yet known, but it will certainly exceed a million euros, so negotiations for funding begin. Because the required amount is so large, Aalto University begins preparing a donation campaign to finance the new receiver.

2020 - Upgrading the radio telescope hardware

Surveying receiver options is underway, but the radio telescope itself also requires refurbishment. The COVID-19 pandemic has driven researchers and students to home offices, but the technical team completes the upgrade of the large dish antenna's rotation mechanisms and motors. The old and worn radome is replaced with a new one. With funding granted by the Research Council of Finland, other telescope and equipment upgrade work can be carried out. Also the major renovation work is completed.

2021 - Funding secured and procurement initiated

Donations total approximately €260,000! In addition to major contributions from the Weisell Foundation and the Magnus Ehrnrooth Foundation, over 80 private benefactors want to support the advancement of Finnish space research!

After extensive scientific and technical evaluations, a concrete list of requirements for the new receiver is finalised. A project of this scale demands an international tender process, which demands additional detailed calculations and plans. The technical requirements alone ultimately fill 16 pages!

2022 - Tender Process and Selecting the Winner

Based on the international tender, the Max Planck Institute for Radio Astronomy in Germany, one of the leading institutions in the field, is selected as the builder. Their proposed technical solution contains new and unexpected innovative solutions, and the overall package offered was highly promising. However, detailed design work takes considerable time, so at this stage no final drawings yet exist.

2023 - First complete design

After the contract is signed, the detailed design phase begins. By summer, the first full design is ready for review—a thick binder filled with drawings, diagrams, and analyses. The team meticulously examines every detail internally before finalizing the plans with the manufacturer. The result? It looks good! Key points of the design are locked in; construction of clear-cut components begins, and the plans focus on ever more detailed specifics.

2024 - New "back-end" for data recording challenges

As the observatory celebrates a milestone anniversary, its own staff are busy, but in Germany the receiver construction progresses. Final designs are received in spring, and after their approval, construction gets comprehensively underway.

Now that the receiver implementation is known, the final required device can also be designed: the "back-end". The telescope's dish collects radiation from a wide area and the receiver converts radio waves into a measurable signal, but only the back-end transforms the raw signal measured by the receiver into a form that can actually be utilised. Its design begins in earnest.

No sufficiently powerful receiver back-end exists anywhere in the world, so one must be built in-house! In an ongoing research project at Metsähovi between the University of Turku and Aalto University, a prototype of a novel digital back-end is developed that could meet the needs of the world's broadest-band receiver. The prototype design, funded by the Research Council of Finland, convinces European Research Council decision-makers to award highly competitive ERC funding for development. The project also secures sponsorship from American component manufacturer AMD and Swiss company Knowledge Resources, around whose technology an entirely novel record-performance Finnish back-end is developed. More information can be found in the news article on the subject.

2025 - Final telescope improvements and preparation for installation

There are a lot of tricky parts: the receiver interior is under vacuum, and the components are cooled with helium to near absolute zero. Vacuum and helium pumps, as well as the back-end and others, require additional space on the radio telescope's receiver platform at ten metres height, and the entire platform is rebuilt during the year.

Furthermore, to maximise measurement accuracy, the telescope's optics are improved by making the subreflector precision-controlled. This allows, for example, gravitational effects on the telescope's support structures to be accounted for when observing in different directions. The subreflector steering system, operating at micrometre precision, is completed, tested, and after lengthy measurement sessions, calibrated for use. As a result, certain frequencies immediately achieved tens of per cent improvement in measurement sensitivity even with the old receivers! The subreflector steering system made entirely in-house, and getting it operational required the work of dozens of people over several years. Workshop master Kjetil Holmberg, in charge of the mechanics and design, estimates that he alone has spend thousands of hours in getting the system operational.

2026 - Final preparations underway

The observatory is preparing for the new receiver's arrival. There is much to prepare, starting from crane safety inspections to installing fibre-optic connections and instrumentation cabinets - not to mention the enormous task of ensuring that this one-of-a-kind and unprecedented, extremely sensitive €1,6 million device is installed correctly the first time, and its functionality tested. This is the top priority for the entire observatory for the whole year!