Radio Amateurs PDF Print E-mail

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 TLE

To 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 modulation

Xatcobeo 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 1

Field Size(bytes) Value 
 RADIO IDXATCOB 
 Protocol headervariable 
 SDU ID0x13 
 Timestampvariable
 SID0xA0 
 +X/-X solar panel voltagevariable
 +X solar panel current2variable
 +X solar panel temperaturevariable
 -X solar panel current2variable
 -X solar panel temperaturevariable
 +Y/-Y solar panel voltage2variable
 +Y solar panel currentvariable
 +Y solar panel temperature2variable 
 -Y solar panel current2variable
 -Y solar panel temperature2variable
 +Z/-Z solar panel voltage2variable
 Paddingvariable
 CRC 2variable 

 

Frame 2

Field Size(bytes) Value 
 RADIO IDXATCOB 
 Protocol headervariable 
 SDU ID0x13 
 Timestampvariable
 SID0xA1 
 +Z solar panel current2variable
 +Z solar panel temperaturevariable
 -Z solar panel current2variable
 -Z solar panel temperaturevariable
 PDM solar panel voltage2variable
 +PDM solar panel currentvariable
 +PDM solar panel temperature2variable 
 -PDM solar panel current2variable
 -PDM solar panel temperature2variable
 Antenna deployment status2variable
 Padding3variable 
 CRCvariable 

 

Frame 3

Field Size(bytes) Value 
 RADIO IDXATCOB 
 Protocol headervariable 
 SDU ID0x13 
 Timestampvariable
 SID0xA2 
 Battery discharge directionvariable
 Battery temperature2variable
 3,3V bus currentvariable
 5V bus current2variable
 Unregulated bus currentvariable
 EPS status2variable
 Battery voltagevariable
 Battery current2variable 
 Corrected bytes by TTC4variable
 RSSI TTC2variable
 Padding1variable
 CRCvariable 

 

Frame 4

Field Size(bytes) Value 
 RADIO IDXATCOB 
 Protocol headervariable 
 SDU ID0x13 
 Timestampvariable
 SID0xA3 
 Received framesvariable
 RX frames with errors4variable
 Transmitted frames4variable
 PA temperature2variable
 VCO temperaturevariable
 RF frequency error in rx2variable
 TTC bootcount4variable
 OBSW mode1variable 
 Padding0variable
 CRC2variable

 

Frame 5 

Field Size(bytes) Value 
 RADIO IDXATCOB 
 Protocol headervariable 
 SDU ID0x13 
 Timestampvariable
 SID0xA4 
 SRAD 5V bus voltagevariable
 SRAD 3,3V bus voltage2variable
 TTC 3,3V bus voltagevariable
 RDS 5V bus voltage2variable
 OBC 1,5V reference voltagevariable
 OBC 3,3V reference voltage2variable
 OBSW last TC executed1variable
 OBSW last eclipse current2variable 
 Number of TCs received4variable
 Number of TCs received (direct)4variable
 Padding0variable
 CRC2variable 
Last Updated on Thursday, 23 February 2012 17:09