I’ve recently finished building a satellite traker based on SATNOGS satellite tracker. The automated tracker uses an Arduino to control a pair of stepper motors that move two cross-yagi antennas (VHF and UHF). The Arduino receives satellite’s azimuth and elevation info using the tracking software Gpredict. Hamlib is then used to establish a link between the computer and Arduino through USB connection via EasyComm III protocol.
The tracker uses two A4988 stepper motor driver, and two geared stepper motors. A weatherproof metal box is used as a case, and rubber seals prevent water from entering. To watch a video about this homebrewed tracker, click here.
I have finished building and testing a DIY Terminal Node Controller (TNC). With a TNC, any radio may encode and decode signals in the Automatic Packet Reporting System (APRS) format. This TNC is based on the home-brewed TNC project by VK3DAN.
The TNC requires a smart phone with APRSdroid connected via bluetooth. It taps directly to a radio through the dedicated audio line-in and line-out ports. I’ve tested this TNC to work with the International Space Station’s (ISS) digipeater at 145.825 MHz, using the digipath: ARISS.
PSAT2 transmits SSTV images at 435.360 MHz (UHF) which may be received using just a DIY Moxon-Yagi satellite antenna, a UHF radio, and a decoder such as Robot 36 running on a smartphone (Android). Here is an image decoded in May 2020, as PSAT2 passes over the Philippines.
SSTV transmission by PSAT2 is active only at daytime. Doppler-effect compensation is necessary to properly receive the transmission. Tune the radio at 435.370 to 435.350 MHz from start to end of the pass. You may decode up to two SSTV images per pass. To watch a a demo video click here.
On October 28, 2019, I was invited by the UP Resilience Institute-NOAH to deliver a talk about amateur radio satellites. In this talk, I’ve discussed how to access these amateur radio satellites, and explained how to setup a home-brewed satellite phone for reliable communication in times of disaster.
I was invited to conduct a live satellite demo at the Pascual Ledesma Naval Station in Cavite, Philippines. We’ve accessed DIWATA2 (PO-101) and had successful contact with JA6PL (Japan), DV2JHA (Pangasinan), and DU1ELT (Cotabato).
This battery-operated radio setup can be easily carried to any remote location. Connect a satellite antenna, turn the radio on, select the pre-programmed uplink and downlink frequencies, and you are ready to make contact!