System overview
The A.R.G.H. radio astronomy station is made up of five integrated subsystems: antenna and dish, RF chain, SDR receiver, control and pointing system, and software and computing system. The architecture follows that of the MIT Haystack Observatory Small Radio Telescope (SRT), adapted to a modern SDR receiver and to the context of Emilia-Romagna.
The system at a glance
| Subsystem | A.R.G.H. solution |
|---|---|
| Dish | Prime focus, 2.4 m diameter, 1–2 GHz band (optimised for 1.42 GHz), estimated gain ~30 dBi |
| Mount | Equatorial, on a pole with a base |
| Feed | Optimised for 1.42 GHz, placed at the focus of the dish |
| LNA | Low-noise amplifier (NF < 0.6 dB) close to the feed |
| Filter | Band-pass centred at 1420 MHz, 20–30 MHz bandwidth |
| Cables | Low-loss coaxial (LMR-400 or equivalent), professional-grade SMA connectors |
| Receiver | SDRplay RSP2pro, 14-bit ADC, up to 10 MHz sampling, over USB |
| Pointing | DC actuators driven by an Arduino or Raspberry Pi |
| Computer | Dedicated Linux PC (Ubuntu LTS), UPS, external NAS for the data |
The signal path
- Dish: collects and concentrates the radio signal
- Feed + LNA: receives the signal and amplifies it with little noise
- RF filter: limits the bandwidth to reduce interference
- Cable to the indoor equipment
- SDR: digitises the signal
- Software: analyses, displays and archives the data
What differs from the SRT
| Aspect | SRT (MIT Haystack) | A.R.G.H. |
|---|---|---|
| Dish | 2.3 m (prototype) | 2.4 m |
| Mount | Motorised azimuth-elevation (SPID) | Equatorial on a pole, DC actuators |
| Receiver | Analogue (1416 MHz local oscillator, mixers, IF stages) with a PCI A/D card, built by the user | Commercial SDR over USB: no receiver to build |
| Software | Dedicated SRT program | GNU Radio, Python (NumPy, SciPy, Astropy), Jupyter |
| Data | — | Open formats (HDF5, CSV) with astronomical metadata |
Overall consumption is low, about 100 W (roughly 876 kWh a year). All the software is open-source.