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Re: Needs help from all ham for Telemetry module and HAM communication module


Thank you for youir email about your satelilte. 

As you know, UO-11, PCsat, PCSAT2, ANDE and 
RAFT all use 145.825 downlink for their packet
signals.  We welcome your satellite on this channel
if it will share the channel.  This means, it has no
more than a say a 20% overall dutycycle.

You described a 60 second cycle with
20 seconds packet data, 
20 seconds sound recording
20 seconds sound playback.

How many times is this 60 second cycle repeated?
If it is continuous, then your satellite would consume
67% of channel capacity and would be a very
high user of this channel.  This would interfere
significantly with the other satellties above.

So can you explain if there is some other timing
that would reduce the overall interference potential
of this mode all around the world?  maybe it is off
most of the time and only turned on over your

Anyway, I am happy to see another 1200 baud
packet satellite on 145.825, but I do want to be
sure we all share the channel well.

Bob Bruninga
USNA Satellite Lab

 If this

>>> "Tanan Rangseeprom Doud" <doud@ji-net.com> 08/29/05 6:28 AM >>>

Thank you very much for your response.Thailand Amateur Radio Satellites
Corporate, as known as TAMSAT GROUP, was established from a group of HAM users
in Thailand that interested in communication in HAM activities.  They formed a
group via VOIP system through Echolink software in HS0AC room.  After that
they developed and found the Satellites Gateway System for Thai HAM users can
communicate with HAM users from the rest of the world via the satellite.  This
communication can be done by repeating the received signal from Down Convertor
430 MHz to 145 MHz from Hamtronic Company.

The government sector in Thailand allows sending and receiving the signal in
VHF 144-146 MHz only.  The frequencies in range 430-438 MHz are used to
receive in HAM activities through the satellite only.  The reason why there
was no allowance from the government sector that control HAM activities to use
the HAM frequency in HAM activities via the satellite frequency UHF was
because the communicating radio devices of the government officers such as
soldiers, policemen, etc. about 99.9% were the devices using in HAM activities
as they were cheap and can be adjusted for a wide range of frequency.  To
allow HAM users to use UHF frequency would be harmed to the government.  But
now, Kington made in China using UHF is very easy to buy from Thai-Burma
border and the price is less than 25 US$ each only.

TAMSAT GROUP has the objectives to unite Thai HAM users to communicate with
HAM users around the world in HAM activities via the satellite, to test and
experiment which will leads to the production of HAM satellite in the future,
to provide the basic technology of communication via HAM satellite and other
communication satellites, and to study in the latest technology in space
activities as well.  Therefore, as we know that Space Affairs Bureau, which is
the government sector, has received the budget to produce the satellite for
experimenting and testing and modules will produce, assembly and launch to
space in China.  Asst. Prof. Kunchit Charmaraman, a project consultant in
Space Affairs Bureau and HAM of Thailand callsign HS1JC, offers TAMSAT GROUP
to propose the project of producing Telemetry module and HAM communication
module.  This module works in Packet Radio System as the same as DOVE DO-17
satellite.  There would be a module to record sound and send back that has a
cycle of work in 1 minute as followed:

00 * 20 second : send the Telemetry about the status of the satellite in
Packet Radio AFSK 1200 bps.

21 * 40 second : record the received sound to IC voice memory.

41 * 60 second : send the recorded sound back to transmitter frequency.

For all the process, using frequency at 145.825 MHz in FM

Therefore, I and TAMSAT GROUP would like to ask for your support for the
circuit in the module together with the knowledge in real production.  I and
my friends in TAMSAT GROUP have proposed the diagram of Telemetry Module and
HAM communication Module to the members of SPACE AFFAIRS BUREAU for approval
to put the module into the satellite of Space Affairs Bureau.  I still missing
some information for the proposal so could you please provide me these
information (includes pictures, if possible) as followed:-

1.The information of the circuit for Telemetry module and HAM communication
module or the similar one and including the circuit of sending and receiving
radio signal set that send and receive signal stable at 145.825 MHz all the
time even there is a reset, the frequency is still the same.
2. The information for the grade of the electronic components for producing
the module that can resist the Cosmic rays and also the heat and freeze
situation in space.  Where can I buy it or are there any places will donate?
3. The programming information to programme  into PIC or Micro Controller Unit
for send Telemetry packet radio output 1200 bps AFSK AX.25 and data input is
ASCII 192000 bps or 9600 bps together with the circuit of the PCB that when
assembled, it is smallest to put into a very small module because I have to
wait for the Space Affairs Bureau to inform me about the size and weight of
the module.
4. The information of antenna system, battery system, and the solar cell
voltage measurement system to measure the voltage used in every points from
modules in major satellite and convert into the information to send to the
Telemetry module and then convert into Packet Radio signal in AFSK 1200 bps.

I and TAMSAT GROUP would like to ask for your favours for these information
and please contact back to me or Mr. Kanchit Charmaraman, HS1JC or Mr.Chavalit
Rasaminil, E20KEW via e-mails or addresses as followed:

Mr. Tanan Rangseeprom HS1JAN e-mail : hs1jan@tamsat.org 

592 Charoennakorn 14 Charoennakorn Road

Khlongtonsai Khlongsan Bangkok 10600 Thailand

Mr. Kunchit Charmaraman HS1JC e-mail : hs1jc@tamsat.org 

125 Vipavadee 18  Chatujak  Bangkok 10900 Thailand

Mr. Chavalit Rasaminil E20KEW e-mail : e20kew@tamsat.org 

258 Moo 12 Suksawat Bangprakok Ratchaburana Bangkok 10140 Thailand

I and member TAMSAT GROUP would like to thank for your favours for providing
very useful information to produce the module.  We hope that in the future we
could produce our own satellite and can use the worldwide frequency in HAM

Best Regards, and 73

Tanan Rangseeprom HS1JAN


e-mail hs1jan@tamsat.org 
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