To answer most of the questions we get from the community, we will try to explain some of the basic functionality of the D-Star ONE communication systems. A more complete tutorial will be uploaded on this website shortly after launch and LEOP. But for those who want to receive the first beacon, the following details should be enough.
D-Star One is a 3U CubeSat which is equipped with four identical radio modules with D-Star capabilities, all being operated in a half-duplex mode. Two modules are used for Telemetry and Telecommand and operate on identical frequencies. Telemetry can be received on 435,7 MHz, the format will be disclosed after launch. Both modules receive, and both modules answer. To prevent information loss, they answer after each other. So each telemetry frame is repeated twice. Both modules have a D-Star Voice-Message Beacon, but it is only activated for Module 1 during LEOP. The Beacon is repeated once in a minute.
The other two modules are dedicated to the radio amateur community. Both modules have the same frequencies, so one of them will be powered down as long as the other one shows no degradation effects. The downlink frequency is 435.525 MHz and the uplink frequency is 437.325 MHz. Also here half-duplex mode is applied. The modules are configured to work as D-Star repeaters, so they retranslate the received messages (or data) on the downlink frequency. They also have a D-Star voice beacon signal.
All modules are operated in a standby-mode. This means that they are in idle for 40 seconds and then in receive mode for 20 seconds. Once a signal has been received, the modules switch to receive mode for five minutes. So it might be necessary to „ping“ the satellite a couple of times until an answer is received.
We use an ICOM radio in split mode to communicate with the satellite. More details on our ground station setup will be included in the above mentioned tutorial.
There will be a small reward for the radio amateur to receive, record and send the first beacon signal from D-Star ONE to email@example.com. More information on this will be published on this site on Nov. 25.