Xatcobeo has its downlink in the UHF radio amateur band. Any ham radio amateur with the appropiate equipment can receive its beacons and TM frames. Latest TLETo be confirmed, but we are tracking object 2012-006F with good results: 2012-006F 1 38082U 12006F 12054.02764552 .00034536 00000-0 92775-3 0 291 2 38082 69.4841 217.2088 0777516 32.2720 332.3574 14.05841791 1347 Frequency and modulationXatcobeo transmits in 437.365 MHz , this frequency was coordinated with IARU to avoid interferences with other satellites in the Amateur Satellite Service. The modulation used by the TTC subsystem is FM with FFSK/MSK at 1200bps in the baseband. One cycle of 1200Hz represents a logic '1', one-and-a-half cycles of 1800Hz represents a logic '0'. Output RF power is 27 dBm. A Turnstile antenna is used on-board. CW beacon Xatcobeo transmits a CW beacon every 75/150 seconds and may transmit housekeeping (HK) frames (see next section) intercalated between beacons if TM is activated. CW is transmitted at 20 WPM as an 800Hz audio on-off keyed signal in FM. CW beacon can contain different parameters: battery voltage (V), signal received (dBm), temperatures (c, Celsius degrees).... TM frames with live HK Xatcobeo may transmit five frames with all the telemetry values of the satellite at the moment of transmission. Each frame has 40 bytes structured as follows: Frame 1Field | Size(bytes) | Value | RADIO ID | 6 | XATCOB | Protocol header | 3 | variable | SDU ID | 1 | 0x13 | Timestamp | 4 | variable | SID | 1 | 0xA0 | +X/-X solar panel voltage | 2 | variable | +X solar panel current | 2 | variable | +X solar panel temperature | 2 | variable | -X solar panel current | 2 | variable | -X solar panel temperature | 2 | variable | +Y/-Y solar panel voltage | 2 | variable | +Y solar panel current | 2 | variable | +Y solar panel temperature | 2 | variable | -Y solar panel current | 2 | variable | -Y solar panel temperature | 2 | variable | +Z/-Z solar panel voltage | 2 | variable | Padding | 1 | variable | CRC | 2 | variable |
Frame 2Field | Size(bytes) | Value | RADIO ID | 6 | XATCOB | Protocol header | 3 | variable | SDU ID | 1 | 0x13 | Timestamp | 4 | variable | SID | 1 | 0xA1 | +Z solar panel current | 2 | variable | +Z solar panel temperature | 2 | variable | -Z solar panel current | 2 | variable | -Z solar panel temperature | 2 | variable | PDM solar panel voltage | 2 | variable | +PDM solar panel current | 2 | variable | +PDM solar panel temperature | 2 | variable | -PDM solar panel current | 2 | variable | -PDM solar panel temperature | 2 | variable | Antenna deployment status | 2 | variable | Padding | 3 | variable | CRC | 2 | variable |
Frame 3Field | Size(bytes) | Value | RADIO ID | 6 | XATCOB | Protocol header | 3 | variable | SDU ID | 1 | 0x13 | Timestamp | 4 | variable | SID | 1 | 0xA2 | Battery discharge direction | 2 | variable | Battery temperature | 2 | variable | 3,3V bus current | 2 | variable | 5V bus current | 2 | variable | Unregulated bus current | 2 | variable | EPS status | 2 | variable | Battery voltage | 2 | variable | Battery current | 2 | variable | Corrected bytes by TTC | 4 | variable | RSSI TTC | 2 | variable | Padding | 1 | variable | CRC | 2 | variable |
Frame 4Field | Size(bytes) | Value | RADIO ID | 6 | XATCOB | Protocol header | 3 | variable | SDU ID | 1 | 0x13 | Timestamp | 4 | variable | SID | 1 | 0xA3 | Received frames | 4 | variable | RX frames with errors | 4 | variable | Transmitted frames | 4 | variable | PA temperature | 2 | variable | VCO temperature | 2 | variable | RF frequency error in rx | 2 | variable | TTC bootcount | 4 | variable | OBSW mode | 1 | variable | Padding | 0 | variable | CRC | 2 | variable |
Frame 5 Field | Size(bytes) | Value | RADIO ID | 6 | XATCOB | Protocol header | 3 | variable | SDU ID | 1 | 0x13 | Timestamp | 4 | variable | SID | 1 | 0xA4 | SRAD 5V bus voltage | 2 | variable | SRAD 3,3V bus voltage | 2 | variable | TTC 3,3V bus voltage | 2 | variable | RDS 5V bus voltage | 2 | variable | OBC 1,5V reference voltage | 2 | variable | OBC 3,3V reference voltage | 2 | variable | OBSW last TC executed | 1 | variable | OBSW last eclipse current | 2 | variable | Number of TCs received | 4 | variable | Number of TCs received (direct) | 4 | variable | Padding | 0 | variable | CRC | 2 | variable |
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