TNC-Pi Raspberry Pi Packet Radio Board

TNC-Pi kit built by Nick Bown 2E0CGW

TNC-Pi kit built by Nick Bown 2E0CGW

The TNC-Pi is a £22 ($40) KISS TNC board which is designed to connect to the GPIO port of the £25 ($35) Raspberry Pi computer board.

It provides a low cost means of using amateur radio AX.25 Packet Radio and APRS.

Nick Bown 2E0CGW has written a well illustrated review of the board. You can download the PDF from TNC-Pi by Nick Bown 2E0CGW

The TNC-Pi kit is available from

Australia’s own BLUEsat ready for launch

The BLUEsat Team - Image credit UNSW

The BLUEsat Team – Image credit UNSW

The University of New South Wales (UNSW) has declared its undergraduate student amateur radio satellite project BLUEsat is complete and ready to be launched into space.

As the official final green light came it was to have a stratospheric balloon test flight near Wagga Wagga in New South Wales. Talks continue on a space launch date.

BLUEsat satellite - Image credit UNSW

BLUEsat satellite – Image credit UNSW

BLUEsat, a 260mm cube weighing around 13 kilograms, will carry a flight computer with transmissions to include a beacon and amateur packet radio using the AX.25 protocol in a “mode J” VHF/UHF configuration.

Magnets will passively stabilise the satellite and align it with the Earth’s magnetic field, and it will be controlled via a dedicated communications groundstation VK2UNS at UNSW is equipped with a Yaesu FT-847 satellite transceiver.

It is hoped BLUEsat will be placed in circular orbit at an altitude of around 750 km that will take it over the poles. At this altitude, the satellite will travel around the Earth at a rate of around once every 90 minutes.

Once in orbit BLUEsat will be a digital amateur radio satellite, which means that voice and data files can be uploaded to it by any amateur radio operator in the world over which the satellite passes.

Students from UNSW will continue to be the primary operators of the satellite while it is in orbit and continue the educational focus throughout the full satellite lifecycle.

Through sponsors helping to pay the bills the student-led project has given a space experience that includes VK2UNS the ground control station.


Basic Low Earth Orbit UNSW Experimental Satellite (BLUEsat) project

January 2012 – Australian BLUEsat LEO undergoes tests

A Ham Radio AX.25 Open Source Soundcard Modem

Audio from AX.25 packet radio - Image credit Sivan Toledo 4X6IZ

Audio from AX.25 packet radio – Image credit Sivan Toledo 4X6IZ

AX.25 packet radio is currently the most popular data protocol for use in CubeSats.

Radio amateur Alejandro Santos LU4EXT is developing extmodem an open source APRS compatible AX.25 packet radio modem.

It is currently capable of both sending and receive packets at 1200 bps AFSK. The main feature of the software is that it is currently running three different demodulators in parallel, increasing the quality of reception. The first modem is Thomas Sailer HB9JNX / AE4WA‘s multimon, the other two are described by Sivan Toledo 4X6IZ in an article in the July/August 2012 issue of QEX.

Download extmodem for Windows from

QEX article – A High-Performance Sound-Card AX.25 Modem

APRS destination address for ham radio satellites

LU4EXT on Twitter

Good News for CubeBug-1



The amateur radio satellite CubeBug-1, also known as El Capitán Beto, launched April 26, 2013, is recovering from the power budget issue that caused the transmitter to be turned off for several days.

This was achieved after one of the AMSAT-LU stations in coordination and in conjunction with Satellogic team, send a command to reconfigure onboard software to turn off attitude control circuits feeding magnetorquers this last weekend .

Telemetry text mode command taken before change can be seen at

CubeBug - command sent shown top and satellite response below

CubeBug – command sent shown top and satellite response below

Operation was with a RTL SDR dongle, connected directly to antenna, using HDSDR recording software as IF mode only, that helped not to record big amount of data from Orbitron connected to DDE, also automatically compensating Doppler.

After reset, Cubebug-1 went to ‘mission state’, batteries showing adequate level of charge.

Good reports were received from several amateurs from different parts of the globe.

This activity is performed as part of the agreement of mutual collaboration that Satellogic and AMSAT-LU signed on July 2013.

The satellite transmits 1200 bps AFSK, on 437.438 MHz, packets are sent every 30 seconds. The signal is at a low level and a directional antenna and preamp are needed for adequate reception.

Cubebug-1 telemetry information at

email: info at

CubeBug-1 carries a packet radio digipeater which it is hoped will be activated for amateur radio use when the primary mission has been completed. Further information at

ANTELSAT a Ham Radio SSTV CubeSat from Uruguay



ANTELSAT is a 2U CubeSat class satellite with a 70 cm SSTV downlink and amateur radio AX.25 Digipeater that is planning a Yasny Dnepr launch in November, 2013. It has been developed by ANTEL (the national telecom service provider) and Facultad de Ingeniería de la Universidad de la República (FING), the State Faculty of Engineering.

The purpose is to build and operate the first satellite ever launched into orbit by Uruguay. Its goal is to develop skills in radio and aerospace engineering, to promote enthusiasm in STEM education at all levels, and provide challenging activities for undergraduate students. The spacecraft is planned to transmit colour and infrared images of the surface of the earth, and to provide several services to radio amateurs (AX.25 digipeater, telemetry beacon, uplink signal report, SSTV downlink). The mission is purely experimental and a technology demonstrator of all the satellite subsystems, which have been custom designed locally.

– VHF receiver on 2m amateur band, 1200bps AX25 protocol.
– Telecommand uplink.
– Store and forward (digipeater) service uplink.
– UHF transmitter on 70cm amateur band:
– CW beacon.
– Telemetry downlink at 1200 bps AX25 protocol.
– Backup downlink for image data via low resolution SSTV.
– Store and forward service downlink.
– S-band transmitter on 2.4 GHz:
– Downlink for payload image data.
– Telemetry backup link.
– 2 redundant transmitters.

Attitude control:
– Attitude determination via magnetometer and photodetectors.
– Active 3-axis control via magnetorquers.


It is reported that ANTEL contributed nearly $700,000 towards the project

ANTELSAT in Google English

IARU Amateur Satellite Frequency Coordination Status

Amateur Radio CubeBug-2 hopes for November 2013 Yasny Dnepr launch



CubeBug-2 is the second technology demonstration mission for a new 2U CubeSat platform design (mechanics, hardware and software) intended to be released as Open Source and Open Hardware for its use in Amateur projects, University projects and Research labs.

This project is sponsored by the Argentinian Ministry of Science, Technology and Productive Innovation. As payload on this second mission, some custom designed components will be tested: an antenna, solar panels, and an on-board computer, a camera, a GPS transceiver and a software defined radio based on COTS components.

CubeBug-2 is expected to be launched as part of a group of CubeSats in a DNEPR rocket launch planned for November 2013 from Yasny.

The satellite will be periodically transmitting AX.25 packets for the Amateur radio community to receive, and after the technology demonstration part of the mission is over, the satellite will enter a mode that will include a Digipeater, science data downloads from the payload (including images and recordings from the SDR, if possible).

Proposing to use 1k2/9k6 FSK/GMSK AX25 on UHF with an AstroDev L1 transceiver.

Its predecessor CubeBug-1 launched on a CZ-2D rocket from the Jiuquan Space Center on April 26, 2013 at 0413 UT.

CubeBug website

IARU Amateur Satellite Frequency Coordination Status