IARU Amateur Satellite Frequency Coordination
 
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Puchaz Updated: 13 Oct 2026   Responsible Operator Jakub Kopec SP9QBR
Supporting Organisation AGH University of Krakow, Faculty of Space Technologies  
Contact Person kuba.kopec2000@gmail.com.nospam  
Headline Details: A 2U CubeSat mission. The PUCHACZ satellite, developed by students of the AGH SatLab student research group at AGH University of Krakow, is an amateur-educational mission as defined in Section 5.4 of the ITU Handbook on Small Satellites (2023). Its missions are listed below, each with the corresponding topic from Section 5.4: 1. Command and control procedures: testing custom command and control procedures based on the CubeSat Space Protocol (CSP), developed specifically for PUCHACZ and future missions. All control of the satellite is performed via our own system of authenticated telecommands on the 70 cm amateur uplink, and the command link itself is the subject of this experiment. The telecommand frame format, including the authentication scheme, is published on our wiki: https://wiki.satlab.agh.edu.pl/s/docs/doc/frame-formats-YWhgKLuGRq Our research goal is to minimise the number of telecommands needed for nominal operations through an optimised communication system between the satellite's components, so that a single short telecommand can trigger a complete sequence of actions on board. We will measure how many telecommands and how much uplink time is needed for typical operations, and publish the results to support future amateur and student missions,which typically rely on a small number of volunteer-operated ground stations. 2. Custom flight software and distributed computer architecture: the spacecraft uses a COTS EnduroSat onboard computer with a single CPU, running custom-configured flight software that manages the satellite bus, developed as part of a master's thesis. In addition, several SatLab-developed boards carry their own microcontrollers and software: the radio, the DZIDA laser payload, the BEAR radiation payload and the camera subsystem. These boards are based primarily on STM32H5 microcontrollers running a real-time operating system. The camera subsystem also includes a Raspberry Pi CM5 running Linux for image acquisition, while an STM32H5 on the same subsystem provides the interface to the rest of the satellite. The boards exchange commands and data with the onboard computer and with each other over the spacecraft network. Onboard memory includes microcontroller flash and RAM, non-volatile memory on the STM32-based boards and larger local storage on the camera computer. Flight software on the SatLab boards covers command handling, timekeeping, health monitoring (housekeeping), logging, watchdog protection and file transfer for the radio-amateur payload (transferring SSDV images from the camera computer to the radio board). Software on the radio and BEAR boards can be updated in orbit with our custom update system, which works over the radio link: new software images are uploaded, stored in spare program memory, verified and activated after a reboot, with the ability to return to the previous working image if the update does not boot correctly. 3. Radiation-tolerant electronics and orbital environment (BEAR payload): research on radiation-tolerant electronics and measurement of the orbital environment. The BEAR payload consists of 12 dosimeters. Nine of them are covered with different biomaterials to measure how well these materials protect electronic components from radiation. The remaining three are left uncovered, serving as a reference and allowing us to measure the orbital radiation environment. 4. Custom radio: testing our in-house radio board, built around a Semtech SX1262 transceiver controlled by an STM32H5 microcontroller. The entire RF chain, including the power amplifier, filters and low-noise amplifier, is duplicated to increase resilience to space radiation and to maintain transmit and receive capability if one of the TX/RX paths is damaged by radiation or other LEO-specific events. 5. Modulation and protocol tests: testing various radio modulation methods and transmission protocols. Our amateur radio transmissions will use LoRa modulation at different spreading factors, and GFSK modulation at 19200 and 38400 bps. Some GFSK transmissions will use IL2P framing. 6. Image transmission: transmitting images taken by the onboard RGB camera in the SSDV format, both in LoRa frames and in IL2P frames using GFSK modulation, according to a schedule published on our wiki, together with reception guides for SX1262-based receivers and SDRs. 7. Message of the Day: a two-way service for licensed amateur operators. An operator transmits a short ping containing their call sign and QTH locator, and the satellite replies with a message that includes the operator's call sign, a counter of answered pings and a daily quote. 8. Pulse power circuit for the optical payload: in-orbit testing of a custom 50 V pulse-forming circuit that powers the laser transmitter, generating pulses 10 to 100 ns long. Non-amateur payloads: PUCHACZ also carries a multispectral Earth observation camera and DZIDA, an experimental optical (laser) communication terminal developed as part of two master's thesis projects. In accordance with Section 5.4, these payloads are not operated in amateur-satellite service bands. The satellite carries a downlink-only S-band transmitter operating on non-amateur frequencies at 2200-2290 MHz under the space research service or Earth exploration-satellite service (to be determined with UKE), for which authorisation will be requested from the regulatory authority responsible for telecommunication. It has two purposes: downlinking all data from the non-amateur payloads, including full-resolution and multispectral imagery, and verifying the efficiency, losses and actual gain of the S-band segment of our own ground station. The optical terminal itself does not use radio frequencies. Only the experiments listed in items 1–8 and their associated telemetry will be transmitted in the amateur bands. Proposing a UHF downlink using LoRa modulation with 125 kHz bandwidth and GFSK at 19k2 or 38k4 bps. Planning a SpaceX launch from Vandenberg NET 1st April 2027 into a 525 km polar orbit. More info at https://wiki.satlab.agh.edu.pl/s/docs/doc/communication-with-puchacz-FApEdtuLZ4
Application Date: 12 Oct 2026   Freq coordination completed on

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