Dear David G0MRF
Thanks you very much for file present of FUNCUBE satellites. I 'm sorry for reply to you late. I have work out of country. on august 4, 2013 have RAST meeting. I have present for JAISAT-1 project. please you seen at web site http://www.qsl.net/rast/ I would like answer the question.of you as follows.
1.Thailand has regular to forbid for transmitt UHF band but can receive the signal for amateur radio satellites only. we need to used VHF band same like transponder FO-29 AO-51 SO-50 and other satellites. for interference from China Thailand and other countries on VHF is normal.
2.Ok, please advice me for circuit diagram of V/U liner transponder.
3.We have to basic design FM repeater use to modify HX1 / RX2A RADIOMETRIX VHF / UHF transmitter module we have change x-tal to 145.90 MHz used x-tal 13.59 MHz and used MC3361 with x-tal IF 10.245 MHz and CML IC FX465 CTCSS Encode/Decode build test it to be via balloon successful.
On this time we and technical team of TAMSAT group need help very urgent. we need advice of circuit diagram or datasheet IC for build V/U Liner transponder for payload 1U cubesat of JAISAT-1 satellite project.
best regards
Tanan Rangseeprom HS1JAN Project Manager of JAISAT-1 member of RAST
----- Original Message ----- From: g0mrf@aol.com To: hs1jan@tamsat.org Sent: Monday, July 29, 2013 5:24 PM Subject: Re: [amsat-bb] V/U Linear Transponder
Dear Tanan.
Thanks for the mail via AMSAT.org
My name is David Bowman G0MRF and I'm a member of the team building FUNcube, due for launch this November.
I can help with transponder design, but there are some points which you need to consider.
1) The use of V band for the uplink will be a poor choice for your location. The interference from China and other countries on 145MHz will mean the transponder will not be usable. Using U band for the uplink is a much better choice.
2) The 100kHz bandwidth is too much for the typical power available from a CubeSat. If you get your RF team to do a link budget analysis, you will see the cubesat power budget will not support 100kHz of bandwidth. Ususally 30kHz is as much as you can do with a 1U cube.
3) You may want to consider a FM 'repeater' as there is now only 1 in orbit, while there are several linear transponder satellites ready to be launched. The FM design will allow you to run a very efficient power amplifier (70%) and power can be saved over oceans and areas of low population by using a 67Hz access tone (CML FX465)
I can assist with design but would need to know if you are planning a 1U 2U or 3U design.
William PE???? is good, but will probably just offer to sell you a transponder.
Regards
David G0MRF
some old info is available at www.g0mrf.com/transponder.htm
The attached powerpoint has some pictures of the UV transponder and other boards in FUNcube from AMSAT-UK
-----Original Message----- From: Tanan Rangseeprom HS1JAN hs1jan@tamsat.org To: amsat-bb amsat-bb@amsat.org Sent: Sun, 28 Jul 2013 17:48 Subject: [amsat-bb] V/U Linear Transponder
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
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