(Photo Credits: STAMINA4SPACE)

On April 2019, a few months after the launch of the Diwata-2 microsatellite, the Space Technology and Applications Mastery, Innovation, and Advancement (STAMINA4SPACE) program announced that its on-board Amateur Radio Unit (ARU) was ready for service.

What does this mean for us?

During disasters, the Diwata-2’s ARU can help transmit messages throughout licensed amateur radio users in the country and reach emergency responders when communication lines on the ground are down. This is because the Diwata-2 carries this communication payload, which was co-developed by Filipino engineers as an additional payload aside from its optical payloads or cameras. The ARU is capable of various downlink and uplink communication functions:

• FM voice repeating (uplink/downlink)
• APRS (Automatic Packet Reporting System) message repeating (uplink/downlink)
• Morse-based beacon (downlink)
• APRS (Automatic Packet Reporting System)-based beacon (downlink)

Uplink frequency refers to the transmission of signals from the on-ground station to the satellite, while downlink frequency refers to the transmission from the satellite to its on-ground receiver. In terms of downlink communication, the ARU sends beacon messages using either Morse-coded CW (Carrier Wave) or APRS packets, depending on scheduled operation.

Thanks to these capabilities, the Radio Amateur Satellite Corporation or AMSAT designated the Diwata-2 as Philippines-OSCAR 101 (PO-101).

Furthermore, the ARU is a spaceborne device placed in a 600 km orbit, meaning that it has an extremely wide coverage, thanks to its high altitude that enables any Licensed Amateur Radio operator, or ham operator, to access the Diwata-2 and communicate with another station both within and outside the Philippines. This high altitude also means that communication won’t be faltered by any weather condition, making it a vital instrument in emergency response during disasters.

Ham operators only need a VHF (Very High Frequency) or UHF (Ultra High Frequency) handheld transmitter and a directional antenna to be able to utilize the ARU. An orbit tracker app, however, is also recommended.

The sun-synchronous orbit of Diwata-2 means that it regularly passes at around noontime and midnight. A more accurate schedule is regularly monitored by the STAMINA4SPACE team and posted through the official Diwata-2 Twitter Page (@Diwata2PH), so operators know when to access the ARU for calls and messages.

For more information, visit http://phl-microsat.upd.edu.ph/diwata2.