LAST UPDATED: Oct.17, 2012
IMPORTANT: BY USING HAM RADIO SERVICE, YOU ARE AGREEING TO BE BOUND BY THE FOLLOWING TERMS.
We provide technical information only to those who comply with the following term.
Please read this term carefully before downloading technical information.
If you have any questions, please contact us.
ISSL PRISM team
HAM Radio Service is available only when all of the following conditions are fulfilled.
- ISSL permits the use of HAM Radio Service.
In case of emergency or other special condition, ISSL might suspend the use of HAM Radio Service.
The information is available on HAM Radio Service Availability.
Be sure to check the website before each pass of your operation.
State of HAM Radio Service
- The satellite pass corresponds to local afternoon.
PRISM’s orbit is sun-synchronous orbit with LTAN (Local Time of Ascending Node) 1 o’clock in the midnight.
This makes two kinds of operational passes; one is from 12 to 4 pm, and the other is from 12 to 4 am.
HAM Radio Service is only available at the former pass group.
- The operation is suspended during ISSL’s operation.
ISSL continues PRISM’s operation as before.
In order to avoid interference, HAM Radio Service during ISSL’s operation is prohibited.
For the ground stations near ISSL, ISSL suspend PRISM operation of Saturday and Sunday afternoon.
ISSL’s operation schedule is available on the website below.
State of HAM Radio Service
- Continuous beacon is received from PRISM.
If you cannot receive CW(Continuous Wave) beacon signal from PRISM, it might indicate defects of your ground station,
or emergency of PRISM. In this case, HAM Radio Service is not available.
Message box Specifications and Limits
- 100 Maximum Messages
The capacity of the message box is limited to 100 messages, corresponding to incremental IDs (from 000 to 099).
Do not write messages if the latest ID is more than 098.
- Message Erasure Condition
ISSL erases and resets the contents of the message box at the end of Saturday.
After the reset, ISSL write the following test message to ID 000.
Test Message: TALK PRISMTestMessage Page**.
** is 2 decimal digits standing for the number of reset.
- Adequate Number of Messages
ISSL want more people to use HAM Radio Service.
Be sure to limit the number of your message to 2 messages per pass and 5 messages per week from Sunday to Saturday.
- Maximum 44-Bytes Message Length
Maximum size of a packet is limited to 44 bytes, containing a 4-bytes header,
1-byte blank (0x20), and 39-bytes messages. Do NOT write longer messages.
The header explains the contents of message. Be sure to inset one of the following headers
at the beginning of your messages.
1. CALL : Call and talk to everyone using HAM Radio Service
2. R*** : Reply to ID ***
3. TALK : The other messages
- Blank of 5th Byte from MSB(Most Significant Bit)
Leave the 5th Byte blank. When downlinked, 5th Byte from MSB is decoded as NULL (0x00).
- Contents of the Message
The message must not violate applicable laws and regulations or disrupt public order and morals.
ISSL denies any liability for the contents of the messages.
Procedures of HAM Radio Service
- Setup of the Ground Station
Prepare the ground station capable of CWE downlink, FM packet downlink, and FM packet uplink.
- Careful Reading of Term and Getting Information
Read the term carefully. If you agree to obey the term, technical information is disclosed to you.
Technical information contains uplink frequency, command formats, and so on.
- Confirmation of Service Availability and Expected Satellite Orbit
Check the availability and get the orbit information.
The information is provided in the following page.
State of HAM Radio Service
- Health Check of Ground Station and PRISM
When PRISM get into your ground station’s range,
confirm that PRISM is sending CWE beacon and your ground station adequately receiving the signal
in CWE mode.
- Confirmation of No Uplinking Ground Station
After you successfully hear beacon signals,
change the ground station mode to FM and confirm that there are no other operators sending commands.
If you do not receive PRISM’s FM downlink for more than 15 seconds, this condition is cleared.
- Health Check of FM Packet Uplink
Firstly, send an Information Command to PRISM and check the health of both uplink and downlink of FM Packet.
PRISM replies approximately 4 seconds after receiving commands.
So, do not send commands for 5 seconds after sending the previous command.
- Registration and Downlink of Messages
After you confirm the current message ID, uplink write commands or read commands.
If the message ID is over 98. Do not send write command.
Note: After you send Write Command, use the Information Command
to confirm the registration. Do not continuously uplink write commands.
- Operator Change
After you write and downlinked the message,
please wait for more than 15 seconds for other potential main operators.
Although Information Commands and Read Commands can be uplinked continuously,
please pay attention to the other operators.
The procedures are also shown in the following block diagram.
Main Operator Rotation
Here, a main operator means an operator uplinking commands to PRISM.
Because this service allows only one operator at a time, please take turns to uplink commands.
Following are the condition to change main operator rotation and start uplinking.
- No FM packets are downlinked from PRISM for more than 20 seconds.
- Uplink and downlink of a message is confirmed.
Possibility of Term Change
The term of PRISM HAM Radio Service may be changed without prior notice.
ISSL will inform the change at Staet of HAM Radio Service page.
If you notice the change of term, be sure to read this term thoroughly and use HAM Radio Service.
Prohibition of Disclosing Technical Information to the Third Party
If you agree to follow this term thoroughly, we will provide you with technical information in the next page.
The information on the next page should not be reprinted or disclosed to the third party without explicit official permission from ISSL.
Also, this service is provided AS IS, and without any warranty expressed or implied as to its accuracy or its completeness,
ISSL denies any liability regarding your operation.
Agree to the term
If there are some people who violate this term and the act may disrupt PRISM or PRISM’s operation,
we might stop all HAM Radio Service by disabling receiver module concerning HAM Radio Service.
This is for PRISM’s safety. In order to maintain HAM Radio Service, please follow this term.
We appreciate your cooperation.