DIY Rotator Controller

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.

To view the circuit diagram, head directly to Stepper Motor Controller using Arduino.

I have posted the sketch below:

//DIY Rotator Controller Sample Sketch
//November 30, 2019
//DIY Rotator Controller
//du1au@nightskyinfocus.com

#include <Stepper.h>  
//initialize Azimuth motor

const int stepperPin1 = 9;                           //Stepper pin
const int stepperPin2 = 10;                          //Stepper pin
const int stepperPin3 = 11;                          //Stepper pin
const int stepperPin4 = 12;                          //Stepper pin
Stepper AZstepper(6330, stepperPin1, stepperPin2, stepperPin3, stepperPin4);  
int motorSpeed = 3;                                  //Motor speed                                             
const int Button1 = 2;                               //Button pin
const int Button2 = 3;                               //Button pin
const int Button3 = 4;                               //Button pin
const int Button4 = 5;                               //Button pin
int speakerPin = 6;                                   //Tones feedback

void setup() {
  Serial.begin(9600);
  pinMode(stepperPin1, OUTPUT);                       //AZStepper pin
  pinMode(stepperPin2, OUTPUT);                       //AZStepper pin
  pinMode(stepperPin3, OUTPUT);                       //AZStepper pin
  pinMode(stepperPin4, OUTPUT);                       //AZStepper pin
  AZstepper.setSpeed(motorSpeed);                     //AZStepper speed
  playLongHighBeep();
 
}
void loop() {
  if(digitalRead(Button3) == HIGH){ //Orange
          playHighTone(); 
          AZstepper.step(1582); 
          playHighTone(); 
    }
   if(digitalRead(Button4) == HIGH){ //Yellow
          playHighTone(); 
          AZstepper.step(-1582); 
          playHighTone();         
    }
     while(digitalRead(Button1) == HIGH){ //Red
        AZstepper.step(1);  
         playLowTone(); 
    }
    while(digitalRead(Button2) == HIGH){ //Green
        AZstepper.step(-1);
        playLowTone();   
    }    
}    
void playHighTone()
{
  tone(speakerPin, 7040, 50);                           //High tone
}
void playLongHighBeep()
{
  tone(speakerPin, 2000, 2000);                        //Long high tone
}
void playLowTone()
{
  tone(speakerPin, 55, 50);                             //Low tone
}

To view all posts on amateur radio, click here.

Related link: Stepper Motor Controller

Night Sky in Focus
Astronomy and Amateur Radio
© Anthony Urbano (Manila, Philippines)

DIY Satellite Radio Wins Go-Kit Contest

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.

Related links:
DIY Satellite Antenna
Portable Satellite Radio Setup
Amateur Radio on the International Space Station (ISS)

Night Sky in Focus
Astronomy and Amateur Radio
© Anthony Urbano (Manila, Philippines)

Talk on Amateur Radio Satellites

On October 28, 2019, I was invited by the UP Resilience Institute-NOAH to deliver a talk about amateur radio satellites.

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.

Related link:
4th UP RI-NOAH Talk on Disaster Resiliency

Night Sky in Focus
Astronomy and Amateur Radio
© Anthony Urbano (Manila, Philippines)

SSTV Images August 3-4, 2019

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.

Related links:
Satellite Communications
My Satellite Antenna

Night Sky in Focus
Astronomy and Amateur Radio
© Anthony Urbano (Manila, Philippines)

Satellite Demo with the Philippine Navy

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).

Naval Sea Systems Command
We used DIWATA2 satellite to bounce a signal from our location in Cavite, to other radio operators in Pangasinan, Cotabato, and as far away as Japan. Copyright: Naval Sea Systems Command, Philippine Navy

For this demo,  I used a home-brew portable satellite radio setup and a DIY satellite antenna.

To view all posts on amateur radio, click here.
Related link: Satellite Demo at a local Hamfest

Night Sky in Focus
Astronomy and Amateur Radio
© Anthony Urbano (Manila, Philippines)

Portable Satellite Radio Setup

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.

Satellite Go-Bag (3).jpg
Everything fits in a small waterproof camera bag, with room to spare for some accessories.

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!

Related links:
DIY Satellite Radio Wins Go-Kit Contest

Night Sky in Focus
Astronomy and Amateur Radio
© Anthony Urbano (Manila, Philippines)

SSTV Images Received February 15-17, 2019

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.

To lean how to receive SSTV images from the ISS, head directly to Receiving Transmissions from the International Space Station.

To learn more about my progress in amateur radio, click here.
Related link: Amateur Radio

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© Anthony Urbano (Manila, Philippines)

SSTV Image from the ISS (October 29, 2018)

SSTV October 29, 2018, 241 am 4G1AWN
SSTV image received and decoded from the International Space Station (ISS) as it passes over the Philippines on October 29, 2018, around 2:41 local time

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).

To learn more about receiving SSTV images from the ISS, click here. To learn more about my progress in amateur radio, click here© Anthony Urbano (Manila, Philippines)