Information for radio amateurs

Mission start

As soon as 19th November 2018 launch of 4. polish satellite – PW-Sat2 – is scheduled. It’s primary mission is a technological tests of sail-based deorbit system. The PW-Sat2 is one of the payloads in SpaceFlight SSO-A The SmallSat Express mission aboard SpaceX’s Falcon 9 rocket. Please be advised that planned launch date may change since it’s quite common for orbital rockets launches – be prepared and follow our socials!

Radio link

The satellite is equipped with full duplex communication module TRxVU Rev. B from Innovative Solutions in Space BV. It operates in amateur bands UHF (downlink) and VHF (uplink). Antenna module consists of two dipole antenna (for uplink/downlink) with linear polarisation. Downlink power equals to 27 dBm (0.5 W). Downlink signal utilizes BPSK modulation, data scrambling according to G3RUH and AX.25 protocol. By default, the satellite transmits its downlink signal at 1200 bps, however it might be changed on request by the OPERation team (via uplink telecommand) up to 9600 bps. Currently set bitrate will be published on PW-Sat2’s Twitter profile, however determination of actual bitrate should be fairly easy by looking at signal spectrum.

What data will be transmitted?

Every 60 seconds the satellite transmits a beacon frame full of telemetric data. 229-bytes long payload of the beacon frame contains the most important information about satellite’s state – among others – temperatures of main subsystems, battery voltage, solar power, on-board computer mission time and experiments state. Other data, such as historical telemetry, experiments data, photos from cameras will be send on request from PW-Sat2’s OPERation team. There is one exception from this rule – deorbit sail experiment will transmit its results on-line (since after sail deployment random tumbling is expected to occur resulting in signal loses and solar energy decrease). Downlink signal of PW-Sat2 will be opened for everyone to receive, decode and interpret data!

HAM radio tools to receive PW-Sat2

HAM radio community plays important role in almost every cubesat mission – receiving and sharing acquired signal with satellites’ owners. Our team has prepared set of tools helping in receiving and demodulation of PW-Sat2 radio signal and upload to cloud-based service afterwards. We believe that data shared to us by community will have big impact on our mission.

 

 

 

Prepared desktop application is available on Linux and Windows platforms (however Ubuntu Linux is the main supported OS). It allows for signal reception utilizing software defined radio receivers (SDR): RTL-SDR, FUNcube Dongle Pro+, ADALM-Pluto SDR as well as “traditional” analogue radio receivers with single sideband demodulator (SSB) via computer’s line-in. Acquired signal from radio receiver is demodulated and deframed. Correctly received frames are classified by means of their type and uploaded to cloud-based application (radio.pw-sat.pl) prepared thanks to co-operation with SoftwareMill company. The cloud-based application allows for frames collection, sharing and telemetry decoding (for beacon frames, labeled as “telemetry frame”). There are available additional features like charts presenting the most important telemetry data.

How to start receiving?

Detailed information are available in our github.com/PW-Sat2/HAMRadio/wiki. A good starting point is to take a look at “Quick start guide”. The wiki pages will be updated as new information (e.g. about orbit, TLE data) will be available.

We encourage to try the software (desktop and cloud parts) right now! In case of any problems – don’t hesitate to mail us (by an e-mail, Messenger, in comment etc.), create an issue on GitHub or simply ask in this thread!

Mission status information

Up to date information about mission status will be published on our Twitter profile – don’t miss anything, follow us now!

Contests for radio amateurs

To encourage you to listen to PW-Sat2 and honour your contribution we would like to issue QSL cards for every HAM radio who will send us (to radio.pw-sat.pl) at least one correct PW-Sat2 frame.

Additionally we’ve prepared contest in three categories:

  • the first received and uploaded frame,
  • the last received and uploaded frame,
  • the most received and uploaded frames.

Shortly after mission we will reveal the winners and honour with packs of PW-Sat2-related gadgets! Find out more about contests!