As one of the most important subsystems aboard the satelite, the Communication subsystem is in charge of the radio link between the satellite and ground station. In previous projects the Laboratory for Space Systems has demonstrated the unique mothodology of communication system development, whereby COTS-based handheld transceivers are utilised. The experience has provided good understanding of communication engineering employed. The communication subsystem of the TSUBAME satellite is being developed based on aquired technology. This is so that the project can contribute to the development of amateur communication technology of the project members.

TSUBAME is an amateur satellite the operation frequency of which will be used for the purposes stated in the IARU's guidelines. TSUBAME has three communication bands, 144MHz VHF band for FM/DTMFG uplink, 430MHz UHF band for CW downlink and another 430MHzx UHF for FM downlink. The frequency coordination is currenly in process by IARU.

Within the TSUBAME project, we specifically focus on the demonstraion of high-speed GMSK downlink and SRLL communication protocols.

THe website for the TSUBAME ground station is now under development. But the general description of LSS's ground station is available from the following link;LSS's ground station

This ground station will be used for the operation of TSUBAME. We have 10 years of experience on using this ground station and we are ready to terminate it in case of any harmful interference.

The configuration of communication equipments has been decided based on technology proven aboard LSS's other satellite projects. Furthermore, TSUBAME will use a new COTS-based handheld transceiver, ID-80 from iCOM Inc. for GMSK downlink. The table showing the configuration of comm. equipment is as follows.

	Frequency [MHz]	Moduration	Protocol	Transceiver	Output power [W]	Power consumption [W]
FM Uplink (Command)	144MHz	AFSK 1200bps / DTMF	AX.25 / DTMF	DJ-C7 (ALINCO)	-	0.3
FM Downlink	430MHz	AFSK 1200bps	AX.25 / SRLL	DJ-C7 (ALINCO)	0.5	2
FM Downlink	430MHz	GMSK 9600bps	AX.25 / SRLL	ID-80 (iCOM)	1	7
CW Downlink	430MHz	CW	CW	Custom made (Cosmowave)	0.1	1