SatNOGS & Pro-Am Ground Stations

The "build a Pi-controlled antenna rotator + RTL-SDR + decoder, point it at every passing cubesat, contribute the demodulated frames to a public database" tier. SatNOGS is the standout pro-am success story of 2010s–2020s amateur radio: a fully open network of ~600+ ground stations across the globe, automatically scheduling and decoding LEO satellite passes, with raw and demodulated data freely accessible.

Strongly cross-linked with Satellite Tracking for pass prediction; Weather Satellites for weather-sat decoding; SDR Receivers for hardware; SDR Software for the broader SDR stack; Pi-based Astro Control for the Pi-at-the-antenna pattern; Classic Pi Projects and MCU Platforms for embedded rotator control.

SatNOGS — the network

• ★ ★ SatNOGS Network — AGPLv3, network.satnogs.org. The world's largest open satellite ground-station network: ~600+ stations across 60+ countries. Anyone can register their station; the central scheduler queues passes you're capable of receiving and your station automatically does the work. Frames decoded by gr-satellites or SatNOGS-DB-aware decoders are pushed back to SatNOGS DB.
  • Operated by Libre Space Foundation (Greece).
  • https://satnogs.org
• ★ ★ SatNOGS DB (db.satnogs.org) — public database of telemetry frames; a satellite operator can pull "all received TLM from my cubesat last month" with one query. The reason satnogs is genuinely useful as a pro-am bridge.
• SatNOGS Wiki — extensive build guides for rotators, antennas, SDRs.

Software stack

• ★ SatNOGS Client — Python, runs on Pi 4 / Pi 5; pulls scheduled passes from Network, drives rotctld + SDR, captures IQ, runs decoder, uploads. AGPLv3.
• ★ gr-satellites (Daniel Estévez, EA4GPZ) — GPL out-of-tree GNU Radio module decoding hundreds of cubesats; the upstream decoder used by SatNOGS for everything beyond plain APT/AFSK.
  • https://github.com/daniestevez/gr-satellites
• gr-saxudp / SoapySDR / GNU Radio — the SDR plumbing layer.
• rotctld / rigctld (Hamlib) — for rotator + radio doppler.

Hardware reference build (Pi-based)

• ★ Pi 4 / Pi 5 — runs SatNOGS Client image; ~$80.
• ★ RTL-SDR Blog v4 — first SDR; ~$30.
• VHF/UHF crossed-yagi (e.g., Arrow II, M2 LEO-Pack, Wimo X-Quad) — directional gain; ~$200–500.
• Az-El rotator — Yaesu G-5500 (paid, ~$700) or SatNOGS Rotator v3 (DIY 3D-print + steppers + Arduino, total ~$250).
• ★ SatNOGS Rotator — open hardware design; community wiki has BOM and STL files; OnStep-style stepper firmware; the OSS rotator pick.
• LNA at antenna — VHF/UHF LNA (RAS Engineering, Mini-Circuits, NooElec); ~$30–80.
• 2.4 GHz / S-band upgrade for HRPT / S-band downlinks: 1+ m parabolic, 2.4 GHz LNA.

Run-without-rotator option

A fixed-zenith omni antenna (Eggbeater II, Lindenblad, QFH) lets you decode passes when overhead without a rotator. SatNOGS supports rotator-less stations; lower SNR but real contribution still possible.

Adjacent organisations / data sources

• ★ AMSAT — global ham-satellite organisation; supports many cubesats.
• ★ AMSAT-DL — operates QO-100 (the geostationary ham transponder on Es'hail-2). Different category from LEO cubesats but heavily linked.
• IARU SatCoord — coordinates ham-satellite frequency assignments.
• R2Cloud — alt-stack to SatNOGS Client; lighter; closed-source-ish; works on Orange Pi too.
• Hams.at — for ham-radio satellite-contact logging — see Satellite Tracking.

Pro-am science contributions

• PROCYON / MarCO / various cubesats — SatNOGS-decoded frames have been used in published papers.
• Reentry tracking — orphan cubesats decay; decode the last beacon from your station.
• Beacon decoding for missing sats — sometimes amateur ground stations are the only receivers still active for older sats.

Books / refs

• The Cubesat Handbook (Cappelletti et al.) — pro-side reference.
• Daniel Estévez's blog (destevez.net) — best ongoing technical write-ups for amateur cubesat decoding.

What's changing in 2024–2026

• Network station count crossed 600 in 2024.
• gr-satellites coverage added many new sats per quarter; Daniel Estévez maintains it nearly single-handed.
• R2Cloud alternative grew share among Orange Pi / x86 stations.
• S-band cubesats — newer designs at 2.2–2.3 GHz; SatNOGS 2024 stations adding S-band feeds.
• Open-source rotators maturing; SatNOGS Rotator v3 design is DIY-buildable for $250.

License / pricing summary

• AGPLv3 / FOSS: SatNOGS Client, SatNOGS Network (server), SatNOGS DB, SatNOGS Rotator design.
• GPL: gr-satellites, GNU Radio, Hamlib.
• Hardware: Pi $80, SDR $30, antenna $200–500, rotator $250–$700, total ~$700–1500 for a respectable station.

Pick this if…

• Contribute to citizen-science satellite decoding: join SatNOGS Network, run a Pi 4 + RTL-SDR + omni or rotator.
• Build the cheapest contributing station: Pi + RTL-SDR + Eggbeater (no rotator) → real contribution still possible.
• Build the OSS rotator: SatNOGS Rotator v3 + Pi-side rotctld.
• Already have a Yaesu G-5500: just plug in; rotctld supports it.
• Want to decode cubesats but not run a station: SatNOGS DB has all decoded frames you'd want, free.
• Interested in ham-radio sat operating instead: see Satellite Tracking.