Op 28-07-13 16:59, Tanan Rangseeprom HS1JAN schreef:

Dear Sir;

My name Mr.Tanan Rangseeprom my callsign HS1JAN. I need help and advice from you for circuit diagram of V/U Liner transponder .I and team want to build it for payload of JAISAT-1 amateur radio satellites of Thailand. JAISAT means is HEART in thai language. JAISAT is Joint Academies Intelligent Satellites for Amateur Radio of Thailand. this is project research and developmentean consists of RAST and Amateur Radio University inThailand both instructor and students.

JAISAT-1 have payload liner transponder V/U uplink at 145.800 - 145.90 MHz and Downlink at 435.10 - 435.20 MHz on CW/SSB to fit in CUBESAT design. but this time I and technical team have no knowledge of the circuit diagram of liner transponder V/U. So you can help and advice me for Electronic Circuit Diagram of liner transponder V/U.

Best Regards

Tanan Rangseeprom HS1JAN / XU7ADN Project Manager of JAISAT-1 member of RAST email : hs1jan@tamsat.org

You could contact William PE1RAH http://www.leijenaarelectronics.nl/index.html for advice or or prebuild transponders. I would advice against V/U but rather go for U/V for several reasons, 1st is grondstation desensing, if you transmit on 435 and recive on 145 you won't have to deal with harmonics, 2nd is pirates in 145.800 to 146 mhz, you are less likely to pick up illigal taxi transmitters and cordless phones on 435 mhz.

Lots of luck on the designs and flying of your sat

73 Andre PE1RDW