GSAT-4, GSAT-8, GSAT-10, GSAT-11, GSAT-12 Transponder and Location Status
G-Sat-4 Satellite also known as HealthSat Satellite. This satellite Launched in April, 2010 by ISRO. Its Mission duration had planned for 7 years but according to my knowledge it's failed to be in orbit.
Longitude: 82°E (planned)
Transponders: Ka-band bent pipe and regenerative transponder
GSAT-8 is communication satellite, for Television and Radio Channels. It is also constructed by ISRO as part of INSAT System. GSAT-8 Satellite was launched on Date of May 21st 2011.
It's planned duration more that for 12 years.
Transponders: 24 Ku band transponders
TV Channels: At this Time 4 Channels are Free to Air From this satellite (Mana TV)
GSAT-10 Satellite also will use for communication so we can say it's communication satellite for purpose of TV Channels, Radio, GPS and other communications. It will field C and Ku band transponders, and includes a navigation payload to augment GAGAN capacity.
It's planned duration for about 15 years.
Transponders: 2 Normal C-band, 12 Extended C-band and 12 Ku-band transponders.
GSAT-11 satellite also is an Indian communication satellite and developing cost of about Rs. 500 crore. GSAT-11 will provide much faster uplinks for a host of communications and broadcasting services, including direct-to-home (DTH television).
The satellite is planned to be launched in 2013
Transponders: It will carry 40 Ku/Ka band transponders.
GSAT-12 Satellite is communication satellite developed by the Indian Space Research Organization, as part of INSAT system India. It had been launched on 15th July 2012.
GSAT-12 Satellite is considered to be a replacement of the aged satellite INSAT-3B and provide services like tele-medicine, point of sale transactions and satellite internet access. its planned duration about 8 years.
Longitude: 83 E
Spectral band 12 C-band Transponders
Transponders 12 Ku-band Transponders