Trevor M5AKA

Amateur Bands Around the World

We often grumble about the fact that the HF/UHF/Microwave allocations in this country are considerably smaller than in other countries such as the USA, Canada and Australia and that we have to share 70cm with other users. However, we should remember that things are far worse elsewhere.

Outside of the English Speaking Nations and Western Europe, Amateurs in many countries don't even have access to the higher frequency allocations.

Below is an email posted to the AMSAT-BB by Tanan Rangseeprom Doud of Thailand AMSAT, which points out that Thai Amateurs are not allowed to transmit on any
part of 70cm, not even the Primary Amateur Satellite segment 435-438 MHz as it's used by the givernment. His English is not perfect but infinately better than my Thai.

The Kington $25 2.5 watt handheld 400-470 MHz radios he mentions can be bought at:
http://search-desc.ebay.co.uk/Kington-UHF_W0QQfltZ9Q5A1QQftsZ2

Incidently Thailand has a rapidly growing Amateur population. It's now about the same as the UK.

73 Trevor M5AKA

From: Tanan Rangseeprom Doud

Dear Paolo Pitacco IW3QBN AMSAT Italy and All HAM of AMSAT

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 the 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
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
activities.

Best Regards,

Tanan Rangseeprom HS1JAN

member TAMSAT GROUP

e-mail hs1jan@tamsat.org

Hi Mr. Tanan Rangseeprom HS1JAN,
I am Paolo Pitacco, IW3QBN, of AMSAT Italy, and I would like respond to your request on amsat-bb reflector.

I have designed and built, some time ago, a telemetry system similar to Microsat (I was a member of design and realization team of ITAMSAT IO-26), for this reason is very simple (eventually) to adapt my project to your needs.

Let me know if you are interested, in any case, you can see some details and pictures avilable at www.amsat-i.org under the chapter "transponder amsat italia".

Best 73,

Paolo, IW3QBN

(take a look at my recent implementation for an amateur rocket telemetry system at www.missilistica.it )

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