This page contains information on the modulation and coding used by 1KUNS-PF, as well as its message formats.
The modulation scheme is similar to the one used for GOMX-3, there are many demodulators already available such as UZ7HO’s SoundModem http://uz7.ho.ua/packetradio.htm . In the “other-versions.zip” file you can find the demodulator specific to our CubeSat. Special thanks to UZ7HO for providing such a great tool.

Frequency: 437.3MHz
Modulation: GMSK
Baud Rate: 9600bps
Beacon Frequency: 1/15s
Telemetry Frequency: On request

In the case you want to know about the protocol, it is structured as follows:
The signal is a simple 9600 baud GMSK, that starts with a preamble of fifty 0xAA that is followed by the Sync Word 0xc9d08a7b.
The next three bytes are the Golay-encoded length field. The first 12 bits are FEC and the latter are the length of the packet.
The data is under a CSP layer that has a four-byte header containing information on the source and destination of the packet.
The data field is followed by a CRC32 of the data and a (255,223) Reed Solomon.
The entire packet after the length is field is randomized using the CCSDS XOR sequence.

In the end, the packet is structured as follows:

Bytes 4 3 4 Length 4 32
Content Sync Word Golay Length CSP Header Data CRC32 Reed Solomon

There are three major type of packets: Beacon, Telemetry and Image.

Beacon:

DATA UNITS OPERATION
beacon_counter >> 8    
beacon_counter    
solar_panel_voltage_0
mV *16
solar_panel_voltage_1
mV *16
solar_panel_voltage_2
mV *16
eps_temp_0 
*C -100
eps_temp_1 
*C -100
eps_temp_2 
*C -100
eps_temp_3
*C  
eps_boot_cause
   
eps_batt_mode
   
solar_panel_current
mA *10
system_input_current
mA *16
battery_voltage
mV *34
radio_PA_temp 
*C -100
tx_count >> 8
   
tx_count
   
rx_count >> 8
   
rx_count
   
obc_temp_0
*C -100
obc_temp_1 
*C -100
ang_velocity_mag
*/s  
magnetometer_x
uT *6
magnetometer_y
uT *6
magnetometer_z 
uT *6
main_axis_of_rot
x,y,z  

Images:
The images are JPEG encoded. They have a two-byte preamble that indicates what number packet is being transmitted, after which 128 bytes of JPEG encoded data follow.