English radio amateurs working on the S band system happy after a successful baud rate change

The SSETI Express team is counting on radio amateurs around the world to help them with data collection, and also offering them the opportunity to use SSETI Express as a transponder. Radio amateurs can help by downlinking housekeeping and payload data and submitting the data to mission control.

SSETI Express UHF and S-Band communications systems will also be combined to form a voice transponder. This will be made freely available to the global radio amateur community at various times during payload operations, once the main mission objectives are complete, together with the mission data downlink.

One of the sub-systems on SSETI Express, the S-Band TX transmitter, has been developed by UK radio amateurs. This has a dual function:

• a high-speed mission data downlink at 38.4 kbps
• a single channel audio transponder in combination with the UHF system

How to take part

To demonstrate that there is a reliable worldwide ground-station network available within the radio amateur fraternity, members are encouraged to participate in the following ways.

Downlink data
Data from SSETI Express can be downlinked on both the UHF and S-Band channels. This telemetry can be decoded and also forwarded over the internet to the SSETI Express mission database.

Uplink friendly telecommands
At specific times, and when outside the range of the ground stations in Denmark and at Svalsat, which is well inside the Artic circle, ‘friendly telecommands’ will be activated on the spacecraft computer. This will enable radio amateurs to use the 9.6 kbps UHF uplink to request particular downlinks including images, housekeeping data, alarm data and payload data from the propulsion system. Both channels will be available for downlinks.

Voice transponding
When the major on-board experiments have been completed, the single-channel U/S audio transponder will be activated and made available to radio amateurs all over the world. To activate the uplink, the usual 67Hz sub audible tone will be required.

DTMF telemetry
The S-Band unit can also be configured to transmit bursts of simple telemetry encoded as DTMF tones

Download software
The SSETI Express team has developed a set of unique software to enable radio amateurs to collect, decode and forward telemetry data. This software package will be freely available prior to the launch date from the Radio Amateur Connection website.

More detailed information concerning orbit data, telemetry formats and other technical parameters can also be found on this site.