Dear All
Thanks respond for help to me
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 of Japanes (FO-29) , AmSat AO-51 , Saudiarabia SO-50 and other
satellites. for interference from China Thailand and other countries on VHF
is normal.
2.Ok, I do not have knowledge 100 khz bandwidth is too much for the over
power. please advice me for 30 khz uplink 145.90-145.92 MHz VHF / 435.10 -
435.12 MHz UHF of liner transponder.
3.We have to design FM repeater use to modify HX1 / RX2A RADIOMETRIX VHF /
UHF transmitter module we have change x-tal to 145.90 MHz / 13.59 MHz and
used MC3361 with x-tal 10.245 MHz and CML IC FX465 CTCSS Encode/Decode build
test it to be successful.
We and technical team of TAMSAT group would like to help and advice for
circuit diagram of V/U transponder same like transponder of Japanes (FO-29)
and other satellites. We had mail to Mr.William Leijenaar PE1RAH but do not
have respond feedback. Mrs Thida of 100watts ham radio magazine of thailand
sugges me to know Mr.William.because she meet him on Tokyo ham fair 2009.
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 satellite project.
best regards
Tanan Rangseeprom HS1JAN
Project Manager of JAISAT-1
member of RAST
email : [email protected]
----- Original Message -----
From: <[email protected]>
To: <[email protected]>
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
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Sent via [email protected]. Opinions expressed are those of the author.
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