[amsat-bb] Re: V/U Linear Transponder

Tanan Rangseeprom HS1JAN hs1jan at tamsat.org
Thu Aug 8 22:02:34 PDT 2013

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 

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 at aol.com>
To: <hs1jan at 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


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 at tamsat.org>
To: amsat-bb <amsat-bb at 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
in thai language. JAISAT is Joint Academies Intelligent Satellites for
Radio of Thailand. this is project research and developmentean consists
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
time I and technical team have no knowledge of the circuit diagram of
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 at tamsat.org

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