Ready for Service: Getting to Know Diwata-2’s Amateur Radio Unit

26 Oct 2020 11:54 AM

(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

The Research Team

The Space Technology and Applications Mastery, Innovation and Advancement (STAMINA4Space) Program
Philippine Universities for Ground Archiving and Data Reception (PUGAD) under STAMINA4Space's STeP-UP Project.

The Development of Philippine Scientific Earth Observation Microsatellite (PHL-Microsat) Program