I have just finished building a DIY controller as part of a home-brewed antenna rotator project. The controller allows simple clockwise and counterclockwise movement of the stepper motor using 4 buttons. The motor may be replaced with a larger one depending on the intended load. I have added an optional speaker for audible feedback.
My portable satellite radio setup won 1st place (VHF-UHF category) in this year’s go-kit (portable equipment) contest as part of the 87th anniversary of the Philippine Amateur Radio Association. It is essentially a satellite phone with collapsible antenna which allows communication with anyone, anywhere in the Philippines and neighboring countries such as Japan, Malaysia, China, Korea, Indonesia, India, Sri Lanka, Singapore, Vietnam, Hong Kong, Taiwan, and even Australia, using only a transmit power of 5W.
The go-kit was built in April 2019 to help the STAMINA4SPACE test our country’s first amateur radio satellite DIWATA2.
Amateur radio satellites are orbiting relay stations that enable long distance communications using only a two-way radio and a home-brewed antenna. Unlike other communications systems like the cellular service and the Internet, satellites do not rely on ground-based communications infrastructure. If a locality is hit with a major disaster, damage to infrastructure will render the cellular phones and the Internet unusable, but satellites in space will continue to function. 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.
To view all posts on amateur radio satellite communications, click here.
I’ve received 6 SSTV images from the International Space Station (ISS) from August 3-4, 2019, from my amateur radio station in Bacoor, Cavite, using a DIY antenna and a portable radio. The app Robot 36 was used to decode the SSTV transmissions. For participating in the SSTV event, I was awarded a certificate.
To learn how to receive SSTV images from the ISS, click here.
I was invited to conduct a live satellite demo at the Philippine Navy as part of the exit presentation of DOST-Balik-Scientist CDR Leo Almazan USN (ret) 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).
The ability to operate off-the-grid is a huge advantage when hunting satellites. Coupled with a portable antenna, this battery-operated radio setup can be easily carried to any remote DX location while requiring only very minimal prep time (5 minutes). Simply connect a satellite antenna, turn the radio on, select the pre-programmed uplink and downlink frequencies, and you are ready to make contact!
The portable satellite radio setup consists of the following:
1. Kenwood TMV71A full-duplex VHF-UHF radio with microphone 2. 12V 8AH lead-acid battery pack with volt meter 3. Sony recorder 4. Headset 5. Other accessories (not shown) such as SWR meter, patch cable, compass, flashlight, notebook, pencil, etc.
This setup has been used recently in a satellite demo at a local hamfest. Since only 5 watts of power is needed to access the FM satellites, this setup lasts for one week of use (about 50 satellite contacts) in a single charge, perfect for DX-peditions!
Here are the Slow Scan Television (SSTV) images I’ve received from the International Space Station (ISS) from February 15-17, 2019, using a Yaesu FT60 hand-held tranceiver and a smartphone with Robot 36 app as decoder. The audio output of the radio is tapped directly to the microphone input of the smartphone for improved signal decoding.
Transmission received from the International Space Station
The International Space Station (ISS) has been transmitting images since October 28 and will continue to do so in the next few days. It transmits in SSTV format—the same format used to send images to Earth during the Apollo missions. The transmissions can be received with any radio tuned at 145.8 MHz, and a decoder app such as Robot 36 (try installing that app and decode this recording).