Make It Tea - public:radio:topics:arduino

60m Transceiver

anonymous@undisclosed.example.com (Anonymous) — Sat, 11 Jul 2026 09:44:34 +0000

←Arduino Projects

60m Transceiver

The 60m transceiver has the following features, which vary according to the loaded firmware

Channelized operation
LCD display
- Frequency
- Mode (SSB / CW)
- Modulation Source (Mic/Key/Data)
- RX / TX status
9MHz IF with Xtal filter
SSB & CW set via mode switch
Approx 3W PEP
Digital mode input/output and PTT via 9-pin D
SSB Mic input via 8-pin round “Icom” connector
Modulation Source (Mic or Data) can chosen via select switch
Scan start switch - scan a preset group of channels - cycles continuously, no “squelch”
- Use of Jenal SC2 CCIR493 Selcal microphone can be supported - including scanning

Arduino Versions

There are several different firmware versions….this is just a sample…

RX Only, with SSB, CW & scan

gm4slv_60m_channels_cwscan_noptt_new_calibration_130523.ino

Firmware (Click to view)

#include <rgb_lcd.h>
#include <si5351.h>
 
char version[] = "v0.1";
 
const long channel_array[] = 
{
5258500,5260000,5261000,5262000,5263000, 5276000,
5278500,5279000,5287200,5290000,5298000,
5301000,5304000,5317000,5320000,5333000,
5334000,5335000,5354000,5355000,5362000,
5363000,5364700,5366500,5371500,5378000,
5379000,5395000,5398500,5403500,
5345000,5245000,5450000,5505000,5680000,
5195000,5616000,5649000
} ;
 
const long scan_array[] = 
{
 5260000,5261000,
 5262000,5263000,
 5366500,5354000,
 5355000,
} ;
 
 
const int mems = sizeof(channel_array)/sizeof(long);
 
const int scan_mems = sizeof(scan_array)/sizeof(long);
 
// the last "no_scan" number channels of
// channel_array are not to be scanned. 
// Put the channels not to be scanned last 
// in the array and update no_scan to reflect. 
 
const int no_scan = 0; 
 
const long bandStart = 5000000;    
const long bandEnd = 6000000;
const long txcio = 9001200;
 
const long cwoffset = 600;
const long filteroffset = 500;
 
volatile int channel = 01;
 
volatile long freq = channel_array[channel];  //      
volatile long oldfreq = 0;
 
 
 
 
 
volatile long currentfreq = 0;
volatile int updatedisplay = 0;
 
// Rotary encoder pins and other inputs
static const int rotAPin = 2;
static const int rotBPin = 3;
static const int pushSwPin = 4;
static const int mictxrxPin = 5;
static const int txRLA1Pin = 7;
static const int txRLA2Pin = 6;
static const int datatxrxPin = 8;
static const int modRLAPin = 9;
static const int modeSWPin = 11;
static const int scanSWPin = 10;
 
volatile int scanning = 0;
volatile int old_scanning = 0;
 
volatile int tx = 0;
volatile int oldtxrx = 0;
 
volatile int mod = 0;
volatile int oldmod = 0;
 
volatile int channel_freq = 0; // push-button to toggle tune method
volatile int old_channel_freq = 0;
 
volatile long scan_freq = scan_array[channel];
volatile long old_scan_freq = 0;
 
volatile int mode = 1; // 1 = USB/LSB, 0 = CW 
volatile int oldmode = 0;
 
// Rotary encoder variables, used by interrupt routines
volatile int rotState = 0;
volatile int rotAval = 1;
volatile int rotBval = 1;
 
 
int digit1 = 0;
int digit2 = 0;
int digit3 = 0;
int digit4 = 0;   
int digit5 = 0;
int digit6 = 0;
int digit7 = 0;
 
// Instantiate the Objects
rgb_lcd lcd;
Si5351 si5351;
 
 
 
byte customChar[8] = {
  0b11111,
  0b11011,
  0b11001,
  0b00000,
  0b11001,
  0b11011,
  0b11111,
  0b11111
};
 
 
 
void setup()
{
 
 
  // Set up frequency and radix switches
  pinMode(rotAPin, INPUT_PULLUP);
  pinMode(rotBPin, INPUT_PULLUP);
  pinMode(pushSwPin, INPUT_PULLUP);
 
  pinMode(mictxrxPin, INPUT_PULLUP);
  pinMode(datatxrxPin, INPUT_PULLUP);
 
  pinMode(modeSWPin, INPUT_PULLUP);
  pinMode(scanSWPin, INPUT_PULLUP);
  pinMode(txRLA1Pin, OUTPUT);
  pinMode(txRLA2Pin, OUTPUT);
  pinMode(modRLAPin, OUTPUT);
 
  digitalWrite(txRLA1Pin, LOW);
  digitalWrite(txRLA2Pin, LOW);
  digitalWrite(modRLAPin, LOW);
 
  // Set up interrupt pins
  attachInterrupt(digitalPinToInterrupt(rotAPin), ISRrotAChange, CHANGE);
  attachInterrupt(digitalPinToInterrupt(rotBPin), ISRrotBChange, CHANGE);
 
  // Initialize the display
  lcd.begin(16, 2);
 
lcd.createChar(0, customChar); // create a new custom character
 
  lcd.cursor();
 
  // Initialize the Si5351
 
  //si5351.init(SI5351_CRYSTAL_LOAD_8PF, 0, -31200);         // 
  //si5351.drive_strength(SI5351_CLK0, SI5351_DRIVE_8MA);   // 2 mA for HB mixers
  //si5351.drive_strength(SI5351_CLK2, SI5351_DRIVE_8MA);   // 2 mA for HB mixers
 
  si5351.init(SI5351_CRYSTAL_LOAD_8PF, 0, 0);
  si5351.set_correction(-34976, SI5351_PLL_INPUT_XO);
  si5351.set_pll(SI5351_PLL_FIXED, SI5351_PLLA);
  si5351.drive_strength(SI5351_CLK0, SI5351_DRIVE_8MA);
  si5351.drive_strength(SI5351_CLK2, SI5351_DRIVE_8MA);
 
 
  // Update display and send start frequency
  UpdateDisplay();
  SendFrequency();
}
 
 
void loop()
{
 
  CheckScanSwitch();
 
  //CheckTXSwitch();
 
  //CheckModSwitch();
 
  CheckModeSwitch();
 
  // Check to see if the freq has changed
  currentfreq = getfreq();                      // Interrupt safe method to get the current frequency
 
  if (currentfreq != oldfreq)
  {
 
    oldfreq = currentfreq;
 
    UpdateDisplay();
    SendFrequency();
 
  }
 
  // Check the rotary encoder (radix) swith
  if (digitalRead(pushSwPin) == LOW)           // Read the rotary encoder switch
  {
    delay(500);
    if (digitalRead(pushSwPin) == LOW)
    {
 
    if (channel_freq == 1)
    {
      channel_freq = 0;
    }
    else if (channel_freq == 0)
    {
      channel_freq = 1;
    }
    //delay(50);
 
    UpdateDisplay();
 
    }
  }
 
} // end of main loop
 
 
long getfreq()
{
  long temp_freq;
  cli();
  temp_freq = freq;
  sei();
  return temp_freq;
}
 
void CheckScanSwitch()
{
 if (digitalRead(scanSWPin) == 0)
 
    {
 
      scanning  = 1;
      scan_freq = 0;
      channel = channel + 1;
 
      if (channel > scan_mems - (no_scan + 1))
            {
              channel = 0;
            }
 
      freq = scan_array[channel];
 
      UpdateDisplay();
      SendFrequency();
      delay(500);
    }
    else
    {
 
 
      if (scanning != old_scanning)
      {
        scanning = 0;
        UpdateDisplay();
      }
      old_scanning = scanning;
    }
 
}
 
//void CheckModSwitch()
//{
//  if (digitalRead(modSWPin) == 0)
//      mod = 0;                             // 0 = Phone
//  else if (digitalRead(modSWPin) == 1)
//      mod = 1;                                 // 1=Data
 
 
//  if (mod != oldmod)
//  {
//    if ( mod == 0)
//      {
//        digitalWrite(modRLAPin,LOW);
//      }
//    else
//      {
//        digitalWrite(modRLAPin,HIGH);
//      } 
//    UpdateDisplay();
//    SendFrequency();
//    oldmod = mod;
//  }
//}
 
 
void CheckModeSwitch()
{
  if (digitalRead(modeSWPin) == 0)
      mode = 0;                             // 0 = CW
  else if (digitalRead(modeSWPin) == 1)
      mode = 1;                                 // 1=SSB
 
 
  if (mode != oldmode)
  {
    if ( mode == 0)
      {
 
      }
    else
      {
 
      } 
    UpdateDisplay();
    SendFrequency();
    oldmode = mode;
  }
}
 
 
 
void CheckTXSwitch()
{
  if (scanning == 0)
  {
  if (digitalRead(mictxrxPin) == 0)
 
  {
    tx = 1;                             // 1=TX
    mod = 0;
 
   }  else if (digitalRead(datatxrxPin) == 0)
 
  {  tx = 1;
     mod = 1;
 
  }  else if (digitalRead(mictxrxPin) == 1)
 
  {  tx = 0;                                 // 0=Phone
 
  } else if (digitalRead(datatxrxPin) == 1)
 
 {   tx = 0;
 
 }
 
  if (tx != oldtxrx)
  {
    if ( tx == 1)
      {
        if ( mod == 0 )
        {
          digitalWrite(modRLAPin,LOW);
        }
        else if ( mod == 1 )
        {
          digitalWrite(modRLAPin,HIGH);
        }
        digitalWrite(txRLA1Pin,HIGH);
        digitalWrite(txRLA2Pin,HIGH);
      }
    else
      {
        digitalWrite(txRLA1Pin,LOW);
        digitalWrite(txRLA2Pin,LOW);   
      }
    UpdateDisplay();
    SendFrequency();
    oldtxrx = tx;
  }
}
}
 
// Interrupt routines
void ISRrotAChange()
{
  if (digitalRead(rotAPin))
  {
    rotAval = 1;
    UpdateRot();
  }
  else
  {
    rotAval = 0;
    UpdateRot();
  }
}
 
 
void ISRrotBChange()
{
  if (digitalRead(rotBPin))
  {
    rotBval = 1;
    UpdateRot();
  }
  else
  {
    rotBval = 0;
    UpdateRot();
  }
}
 
 
// Determine which way the rotary encoder is rotating and action as required
void UpdateRot()
{
  switch (rotState)
  {
    case 0:                                         // Idle state, look for direction
      if (!rotBval)
        rotState = 1;                               // CW 1
      if (!rotAval)
        rotState = 11;                              // CCW 1
      break;
 
    case 1:                                         // CW, wait for A low while B is low
      if (!rotBval)
      {
        if (!rotAval)
        {
          // either increment the radix or freq
          if (channel_freq == 1)
          {
            updatedisplay = 1;
            if (mode == 1)
            {
            freq = freq + 500;
            }
            else
            {
              freq = freq + 100;
            }
            if (freq > bandEnd)
            {
              freq = bandEnd;
            }
 
          }
          else
          {
            channel = channel + 1;
 
            if (channel > mems -1)
            {
              channel = 0;
            }
            freq = channel_array[channel]; 
          }
          rotState = 2;                             // CW 2
        }
      }
      else if (rotAval)
        rotState = 0;                               // It was just a glitch on B, go back to start
      break;
 
    case 2:                                         // CW, wait for B high
      if (rotBval)
        rotState = 3;                               // CW 3
      break;
 
    case 3:                                         // CW, wait for A high
      if (rotAval)
        rotState = 0;                               // back to idle (detent) state
      break;
 
    case 11:                                        // CCW, wait for B low while A is low
      if (!rotAval)
      {
        if (!rotBval)
        {
          if ( channel_freq == 1 )
          {
            updatedisplay = 1;
 
            if (mode == 1)
            {
            freq = freq - 500;
            }
            else
            {
              freq = freq - 100;
            }
 
            if (freq < bandStart)
            {
              freq = bandStart;
            }
          }
          else
          {
            channel = channel - 1;
 
            if (channel < 0)
             {
              channel = mems - 1;
             }
            freq = channel_array[channel];
 
          }
          rotState = 12;                            // CCW 2
        }
      }
      else if (rotBval)
        rotState = 0;                               // It was just a glitch on A, go back to start
      break;
 
    case 12:                                        // CCW, wait for A high
      if (rotAval)
        rotState = 13;                              // CCW 3
      break;
 
    case 13:                                        // CCW, wait for B high
      if (rotBval)
        rotState = 0;                               // back to idle (detent) state
      break;
  }
}
 
 
void UpdateDisplay()
{
 
 
    digit1 = (freq%10);
    digit2 = ((freq/10)%10);
    digit3 = ((freq/100)%10);
    digit4 = ((freq/1000)%10);   
    digit5 = ((freq/10000)%10);
    digit6 = ((freq/100000)%10);
    digit7 = ((freq/1000000)%10);
 
 
  lcd.setCursor(0,0);
  lcd.print(digit7);
  lcd.setCursor(1,0);
  lcd.print(",");
  lcd.setCursor(2,0);
  lcd.print(digit6);
  lcd.setCursor(3,0);
  lcd.print(digit5);
  lcd.setCursor(4,0);
  lcd.print(digit4);
  lcd.setCursor(5,0);
  lcd.print(".");
  lcd.setCursor(6,0);
  lcd.print(digit3);
  lcd.setCursor(7,0);
  lcd.print(digit2);
 
  lcd.setCursor(8,0);
  lcd.print("kHz");
 
 
 
 
  lcd.setCursor(0,1);
  lcd.print("        ");
 
 
 
  lcd.setCursor(channel,1); 
 
 
if (scanning == 1)
{
   // lcd.print("|");
 
  lcd.write((byte)0);  // print the custom char at (2, 0)
}
 
 /*
  //if (channel < 10)
  //{
  //lcd.print("0");
  //}
  //lcd.print(channel);
 
 lcd.setCursor(0,1);
 if (freq == 5287200 )
 {
  //lcd.setCursor(3,1);
  //lcd.print("    ");
  //lcd.setCursor(3,1);
  lcd.print("WSPR1");
 }
 
 if (freq == 5290000 )
 {
  //lcd.setCursor(3,1);
  //lcd.print("    ");
  //lcd.setCursor(3,1);
  lcd.print("ORK");
 }
 
 if (freq == 5364700 )
 {
  //lcd.setCursor(3,1);
  //lcd.print("    ");
  //lcd.setCursor(3,1);
  lcd.print("WSPR2");
 }
 
 if (freq == 5450000 )
 {
  //lcd.setCursor(3,1);
  //lcd.print("    ");
  //lcd.setCursor(3,1);
  lcd.print("RAF");
 }
 
 if (freq == 5505000 )
 {
  //lcd.setCursor(3,1);
  //lcd.print("    ");
  //lcd.setCursor(3,1);
  lcd.print("EIP");
 }
 
if (freq == 5317000 )
 {
  //lcd.setCursor(3,1);
  //lcd.print("    ");
  //lcd.setCursor(3,1);
  lcd.print("VMARS");
 }
 
if (freq == 5366500 )
 {
  //lcd.setCursor(3,1);
  //lcd.print("    ");
  //lcd.setCursor(3,1);
  lcd.print("FK");
 }
 
if (freq == 5258500 )
 {
  //lcd.setCursor(3,1);
  //lcd.print("    ");
  //lcd.setCursor(3,1);
  lcd.print("FA");
 }
 
if (freq == 5278500 )
 {
  //lcd.setCursor(3,1);
  //lcd.print("    ");
  //lcd.setCursor(3,1);
  lcd.print("FB");
 }
 
if (freq == 5288500 )
 {
  //lcd.setCursor(3,1);
  //lcd.print("    ");
  //lcd.setCursor(3,1);
  lcd.print("FC");
 }
 
if (freq == 5371500 )
 {
  //lcd.setCursor(3,1);
  //lcd.print("    ");
  //lcd.setCursor(3,1);
  lcd.print("FL");
 }
 
if (freq == 5398500 )
 {
  //lcd.setCursor(3,1);
  //lcd.print("    ");
  //lcd.setCursor(3,1);
  lcd.print("FE");
 }
 
 if (freq == 5403500 )
 {
  //lcd.setCursor(3,1);
  //lcd.print("    ");
  //lcd.setCursor(3,1);
  lcd.print("FM");
 }
 
if (freq == 5195000 )
 {
  //lcd.setCursor(3,1);
  //lcd.print("    ");
  //lcd.setCursor(3,1);
  lcd.print("DRA5");
 }
 
if (freq == 5262000 )
 {
  //lcd.setCursor(3,1);
  //lcd.print("    ");
  //lcd.setCursor(3,1);
  lcd.print("QRP CW");
 }
 
 
if ((freq >= 5259000) && (freq < 5262000) )
 {
  //lcd.setCursor(3,1);
  //lcd.print("    ");
  //lcd.setCursor(3,1);
  lcd.print("CW");
 }
 
 
 
*/
 
 
 
 
 lcd.setCursor(14,0);
 
if (tx == 0)
   { lcd.print("RX");
 
   } else if (tx == 1)
   {
    lcd.print("TX");
  }
 
  lcd.setCursor(8,1);
  if (mode == 1)
  {
    lcd.print("SSB");
  }
  if (mode == 0)
  {
    lcd.print(" CW");
  }
 
  lcd.setCursor(12,1);
  if ( mode == 0 )
  {
    lcd.print(" Key");
    //lcd.print(version);
  }
  else
 
  {
    if (mod == 0)
  {
    lcd.print(" Mic");
    //lcd.print(version);
  }
  else
  {
   lcd.print("Data");
   //lcd.print(version);
  }
}
if (channel_freq == 1)
{
  if (mode == 1)
  {
    lcd.setCursor(6,0);
  }
  else if ( mode == 0 )
  {
    lcd.setCursor(7,0);
  }
  lcd.blink();
}
else
{
  lcd.noBlink();
}
} // end of updatedisplay()
 
 
void SendFrequency()
 
 
 
 
{
 
if (mode == 1 ) // SSB
 
  {
    si5351.set_freq(((txcio + freq) * 100ULL), SI5351_CLK0);     // VFO
    si5351.set_freq((txcio * 100ULL), SI5351_CLK2);              // BFO
 
  }
 
else if (mode == 0) // CW
 
  if ( tx == 0 )
 
  {
 
    si5351.set_freq(((txcio + freq - cwoffset - filteroffset) * 100ULL), SI5351_CLK0);    // VFO
    si5351.set_freq(((txcio  - filteroffset) * 100ULL), SI5351_CLK2);                     // BFO
 
  }
 
  else if (tx == 1 )
 
  {
 
    si5351.set_freq(((txcio + freq - cwoffset - filteroffset) * 100ULL), SI5351_CLK0);    // VFO
    si5351.set_freq(((txcio - cwoffset - filteroffset) * 100ULL), SI5351_CLK2);           // BFO
 
  }
 
} // end of sendfrequency()

Full TX/RX - with SSB, CW & Scan

gm4slv_60m_channels_cwscan_ptt_new_calibration_230823.ino

Firmware (Click to view)

#include <rgb_lcd.h>
#include <si5351.h>
 
char version[] = "v0.1";
 
const long channel_array[] = 
{
5258500,5260000,5261000,5262000,5263000, 5276000,
5278500,5279000,5287200,5290000,5298000,
5301000,5304000,5317000,5320000,5333000,
5334000,5335000,5354000,5355000,5362000,
5363000,5364700,5366500,5371500,5378000,
5379000,5395000,5398500,5403500,
5345000,5245000,5450000,5505000,5680000,
5195000,5616000,5649000
} ;
 
const long scan_array[] = 
{
 5260000,5261000,
 5262000,5263000,
 5366500,5354000,
 5355000,
} ;
 
 
const int mems = sizeof(channel_array)/sizeof(long);
 
const int scan_mems = sizeof(scan_array)/sizeof(long);
 
// the last "no_scan" number channels of
// channel_array are not to be scanned. 
// Put the channels not to be scanned last 
// in the array and update no_scan to reflect. 
 
const int no_scan = 0; 
 
const long bandStart = 5000000;    
const long bandEnd = 6000000;
const long txcio = 9001200;
 
const long cwoffset = 600;
const long filteroffset = 500;
 
volatile int channel = 01;
 
volatile long freq = channel_array[channel];  //      
volatile long oldfreq = 0;
 
 
 
 
 
volatile long currentfreq = 0;
volatile int updatedisplay = 0;
 
// Rotary encoder pins and other inputs
static const int rotAPin = 2;
static const int rotBPin = 3;
static const int pushSwPin = 4;
static const int mictxrxPin = 5;
static const int txRLA1Pin = 7;
static const int txRLA2Pin = 6;
static const int datatxrxPin = 8;
static const int modRLAPin = 9;
static const int modeSWPin = 11;
static const int scanSWPin = 10;
 
volatile int scanning = 0;
volatile int old_scanning = 0;
 
volatile int tx = 0;
volatile int oldtxrx = 0;
 
volatile int mod = 0;
volatile int oldmod = 0;
 
volatile int channel_freq = 0; // push-button to toggle tune method
volatile int old_channel_freq = 0;
 
volatile long scan_freq = scan_array[channel];
volatile long old_scan_freq = 0;
 
volatile int mode = 1; // 1 = USB/LSB, 0 = CW 
volatile int oldmode = 0;
 
// Rotary encoder variables, used by interrupt routines
volatile int rotState = 0;
volatile int rotAval = 1;
volatile int rotBval = 1;
 
 
int digit1 = 0;
int digit2 = 0;
int digit3 = 0;
int digit4 = 0;   
int digit5 = 0;
int digit6 = 0;
int digit7 = 0;
 
// Instantiate the Objects
rgb_lcd lcd;
Si5351 si5351;
 
 
 
byte customChar[8] = {
  0b11111,
  0b11011,
  0b11001,
  0b00000,
  0b11001,
  0b11011,
  0b11111,
  0b11111
};
 
 
 
void setup()
{
 
 
  // Set up frequency and radix switches
  pinMode(rotAPin, INPUT_PULLUP);
  pinMode(rotBPin, INPUT_PULLUP);
  pinMode(pushSwPin, INPUT_PULLUP);
 
  pinMode(mictxrxPin, INPUT_PULLUP);
  pinMode(datatxrxPin, INPUT_PULLUP);
 
  pinMode(modeSWPin, INPUT_PULLUP);
  pinMode(scanSWPin, INPUT_PULLUP);
  pinMode(txRLA1Pin, OUTPUT);
  pinMode(txRLA2Pin, OUTPUT);
  pinMode(modRLAPin, OUTPUT);
 
  digitalWrite(txRLA1Pin, LOW);
  digitalWrite(txRLA2Pin, LOW);
  digitalWrite(modRLAPin, LOW);
 
  // Set up interrupt pins
  attachInterrupt(digitalPinToInterrupt(rotAPin), ISRrotAChange, CHANGE);
  attachInterrupt(digitalPinToInterrupt(rotBPin), ISRrotBChange, CHANGE);
 
  // Initialize the display
  lcd.begin(16, 2);
 
lcd.createChar(0, customChar); // create a new custom character
 
  lcd.cursor();
 
  // Initialize the Si5351
 
  //si5351.init(SI5351_CRYSTAL_LOAD_8PF, 0, -31200);         // 
  //si5351.drive_strength(SI5351_CLK0, SI5351_DRIVE_8MA);   // 2 mA for HB mixers
  //si5351.drive_strength(SI5351_CLK2, SI5351_DRIVE_8MA);   // 2 mA for HB mixers
 
  si5351.init(SI5351_CRYSTAL_LOAD_8PF, 0, 0);
  si5351.set_correction(-34976, SI5351_PLL_INPUT_XO);
  si5351.set_pll(SI5351_PLL_FIXED, SI5351_PLLA);
  si5351.drive_strength(SI5351_CLK0, SI5351_DRIVE_8MA);
  si5351.drive_strength(SI5351_CLK2, SI5351_DRIVE_8MA);
 
 
  // Update display and send start frequency
  UpdateDisplay();
  SendFrequency();
}
 
 
void loop()
{
 
  CheckScanSwitch();
 
  CheckTXSwitch();
 
  //CheckModSwitch();
 
  CheckModeSwitch();
 
  // Check to see if the freq has changed
  currentfreq = getfreq();                      // Interrupt safe method to get the current frequency
 
  if (currentfreq != oldfreq)
  {
 
    oldfreq = currentfreq;
 
    UpdateDisplay();
    SendFrequency();
 
  }
 
  // Check the rotary encoder (radix) swith
  if (digitalRead(pushSwPin) == LOW)           // Read the rotary encoder switch
  {
    delay(500);
    if (digitalRead(pushSwPin) == LOW)
    {
 
    if (channel_freq == 1)
    {
      channel_freq = 0;
    }
    else if (channel_freq == 0)
    {
      channel_freq = 1;
    }
    //delay(50);
 
    UpdateDisplay();
 
    }
  }
 
} // end of main loop
 
 
long getfreq()
{
  long temp_freq;
  cli();
  temp_freq = freq;
  sei();
  return temp_freq;
}
 
void CheckScanSwitch()
{
 if (digitalRead(scanSWPin) == 0)
 
    {
 
      scanning  = 1;
      scan_freq = 0;
      channel = channel + 1;
 
      if (channel > scan_mems - (no_scan + 1))
            {
              channel = 0;
            }
 
      freq = scan_array[channel];
 
      UpdateDisplay();
      SendFrequency();
      delay(500);
    }
    else
    {
 
 
      if (scanning != old_scanning)
      {
        scanning = 0;
        UpdateDisplay();
      }
      old_scanning = scanning;
    }
 
}
 
//void CheckModSwitch()
//{
//  if (digitalRead(modSWPin) == 0)
//      mod = 0;                             // 0 = Phone
//  else if (digitalRead(modSWPin) == 1)
//      mod = 1;                                 // 1=Data
 
 
//  if (mod != oldmod)
//  {
//    if ( mod == 0)
//      {
//        digitalWrite(modRLAPin,LOW);
//      }
//    else
//      {
//        digitalWrite(modRLAPin,HIGH);
//      } 
//    UpdateDisplay();
//    SendFrequency();
//    oldmod = mod;
//  }
//}
 
 
void CheckModeSwitch()
{
  if (digitalRead(modeSWPin) == 0)
      mode = 0;                             // 0 = CW
  else if (digitalRead(modeSWPin) == 1)
      mode = 1;                                 // 1=SSB
 
 
  if (mode != oldmode)
  {
    if ( mode == 0)
      {
 
      }
    else
      {
 
      } 
    UpdateDisplay();
    SendFrequency();
    oldmode = mode;
  }
}
 
 
 
void CheckTXSwitch()
{
  if (scanning == 0)
  {
  if (digitalRead(mictxrxPin) == 0)
 
  {
    tx = 1;                             // 1=TX
    mod = 0;
 
   }  else if (digitalRead(datatxrxPin) == 0)
 
  {  tx = 1;
     mod = 1;
 
  }  else if (digitalRead(mictxrxPin) == 1)
 
  {  tx = 0;                                 // 0=Phone
 
  } else if (digitalRead(datatxrxPin) == 1)
 
 {   tx = 0;
 
 }
 
  if (tx != oldtxrx)
  {
    if ( tx == 1)
      {
        if ( mod == 0 )
        {
          digitalWrite(modRLAPin,LOW);
        }
        else if ( mod == 1 )
        {
          digitalWrite(modRLAPin,HIGH);
        }
        digitalWrite(txRLA1Pin,HIGH);
        digitalWrite(txRLA2Pin,HIGH);
      }
    else
      {
        digitalWrite(txRLA1Pin,LOW);
        digitalWrite(txRLA2Pin,LOW);   
      }
    UpdateDisplay();
    SendFrequency();
    oldtxrx = tx;
  }
}
}
 
// Interrupt routines
void ISRrotAChange()
{
  if (digitalRead(rotAPin))
  {
    rotAval = 1;
    UpdateRot();
  }
  else
  {
    rotAval = 0;
    UpdateRot();
  }
}
 
 
void ISRrotBChange()
{
  if (digitalRead(rotBPin))
  {
    rotBval = 1;
    UpdateRot();
  }
  else
  {
    rotBval = 0;
    UpdateRot();
  }
}
 
 
// Determine which way the rotary encoder is rotating and action as required
void UpdateRot()
{
  switch (rotState)
  {
    case 0:                                         // Idle state, look for direction
      if (!rotBval)
        rotState = 1;                               // CW 1
      if (!rotAval)
        rotState = 11;                              // CCW 1
      break;
 
    case 1:                                         // CW, wait for A low while B is low
      if (!rotBval)
      {
        if (!rotAval)
        {
          // either increment the radix or freq
          if (channel_freq == 1)
          {
            updatedisplay = 1;
            if (mode == 1)
            {
            freq = freq + 500;
            }
            else
            {
              freq = freq + 100;
            }
            if (freq > bandEnd)
            {
              freq = bandEnd;
            }
 
          }
          else
          {
            channel = channel + 1;
 
            if (channel > mems -1)
            {
              channel = 0;
            }
            freq = channel_array[channel]; 
          }
          rotState = 2;                             // CW 2
        }
      }
      else if (rotAval)
        rotState = 0;                               // It was just a glitch on B, go back to start
      break;
 
    case 2:                                         // CW, wait for B high
      if (rotBval)
        rotState = 3;                               // CW 3
      break;
 
    case 3:                                         // CW, wait for A high
      if (rotAval)
        rotState = 0;                               // back to idle (detent) state
      break;
 
    case 11:                                        // CCW, wait for B low while A is low
      if (!rotAval)
      {
        if (!rotBval)
        {
          if ( channel_freq == 1 )
          {
            updatedisplay = 1;
 
            if (mode == 1)
            {
            freq = freq - 500;
            }
            else
            {
              freq = freq - 100;
            }
 
            if (freq < bandStart)
            {
              freq = bandStart;
            }
          }
          else
          {
            channel = channel - 1;
 
            if (channel < 0)
             {
              channel = mems - 1;
             }
            freq = channel_array[channel];
 
          }
          rotState = 12;                            // CCW 2
        }
      }
      else if (rotBval)
        rotState = 0;                               // It was just a glitch on A, go back to start
      break;
 
    case 12:                                        // CCW, wait for A high
      if (rotAval)
        rotState = 13;                              // CCW 3
      break;
 
    case 13:                                        // CCW, wait for B high
      if (rotBval)
        rotState = 0;                               // back to idle (detent) state
      break;
  }
}
 
 
void UpdateDisplay()
{
 
 
    digit1 = (freq%10);
    digit2 = ((freq/10)%10);
    digit3 = ((freq/100)%10);
    digit4 = ((freq/1000)%10);   
    digit5 = ((freq/10000)%10);
    digit6 = ((freq/100000)%10);
    digit7 = ((freq/1000000)%10);
 
 
  lcd.setCursor(0,0);
  lcd.print(digit7);
  lcd.setCursor(1,0);
  lcd.print(",");
  lcd.setCursor(2,0);
  lcd.print(digit6);
  lcd.setCursor(3,0);
  lcd.print(digit5);
  lcd.setCursor(4,0);
  lcd.print(digit4);
  lcd.setCursor(5,0);
  lcd.print(".");
  lcd.setCursor(6,0);
  lcd.print(digit3);
  lcd.setCursor(7,0);
  lcd.print(digit2);
 
  lcd.setCursor(8,0);
  lcd.print("kHz");
 
 
 
 
  lcd.setCursor(0,1);
  lcd.print("        ");
 
 
 
  lcd.setCursor(channel,1); 
 
 
if (scanning == 1)
{
   // lcd.print("|");
 
  lcd.write((byte)0);  // print the custom char at (2, 0)
}
 
 /*
  //if (channel < 10)
  //{
  //lcd.print("0");
  //}
  //lcd.print(channel);
 
 lcd.setCursor(0,1);
 if (freq == 5287200 )
 {
  //lcd.setCursor(3,1);
  //lcd.print("    ");
  //lcd.setCursor(3,1);
  lcd.print("WSPR1");
 }
 
 if (freq == 5290000 )
 {
  //lcd.setCursor(3,1);
  //lcd.print("    ");
  //lcd.setCursor(3,1);
  lcd.print("ORK");
 }
 
 if (freq == 5364700 )
 {
  //lcd.setCursor(3,1);
  //lcd.print("    ");
  //lcd.setCursor(3,1);
  lcd.print("WSPR2");
 }
 
 if (freq == 5450000 )
 {
  //lcd.setCursor(3,1);
  //lcd.print("    ");
  //lcd.setCursor(3,1);
  lcd.print("RAF");
 }
 
 if (freq == 5505000 )
 {
  //lcd.setCursor(3,1);
  //lcd.print("    ");
  //lcd.setCursor(3,1);
  lcd.print("EIP");
 }
 
if (freq == 5317000 )
 {
  //lcd.setCursor(3,1);
  //lcd.print("    ");
  //lcd.setCursor(3,1);
  lcd.print("VMARS");
 }
 
if (freq == 5366500 )
 {
  //lcd.setCursor(3,1);
  //lcd.print("    ");
  //lcd.setCursor(3,1);
  lcd.print("FK");
 }
 
if (freq == 5258500 )
 {
  //lcd.setCursor(3,1);
  //lcd.print("    ");
  //lcd.setCursor(3,1);
  lcd.print("FA");
 }
 
if (freq == 5278500 )
 {
  //lcd.setCursor(3,1);
  //lcd.print("    ");
  //lcd.setCursor(3,1);
  lcd.print("FB");
 }
 
if (freq == 5288500 )
 {
  //lcd.setCursor(3,1);
  //lcd.print("    ");
  //lcd.setCursor(3,1);
  lcd.print("FC");
 }
 
if (freq == 5371500 )
 {
  //lcd.setCursor(3,1);
  //lcd.print("    ");
  //lcd.setCursor(3,1);
  lcd.print("FL");
 }
 
if (freq == 5398500 )
 {
  //lcd.setCursor(3,1);
  //lcd.print("    ");
  //lcd.setCursor(3,1);
  lcd.print("FE");
 }
 
 if (freq == 5403500 )
 {
  //lcd.setCursor(3,1);
  //lcd.print("    ");
  //lcd.setCursor(3,1);
  lcd.print("FM");
 }
 
if (freq == 5195000 )
 {
  //lcd.setCursor(3,1);
  //lcd.print("    ");
  //lcd.setCursor(3,1);
  lcd.print("DRA5");
 }
 
if (freq == 5262000 )
 {
  //lcd.setCursor(3,1);
  //lcd.print("    ");
  //lcd.setCursor(3,1);
  lcd.print("QRP CW");
 }
 
 
if ((freq >= 5259000) && (freq < 5262000) )
 {
  //lcd.setCursor(3,1);
  //lcd.print("    ");
  //lcd.setCursor(3,1);
  lcd.print("CW");
 }
 
 
 
*/
 
 
 
 
 lcd.setCursor(14,0);
 
if (tx == 0)
   { lcd.print("RX");
 
   } else if (tx == 1)
   {
    lcd.print("TX");
  }
 
  lcd.setCursor(8,1);
  if (mode == 1)
  {
    lcd.print("SSB");
  }
  if (mode == 0)
  {
    lcd.print(" CW");
  }
 
  lcd.setCursor(12,1);
  if ( mode == 0 )
  {
    lcd.print(" Key");
    //lcd.print(version);
  }
  else
 
  {
    if (mod == 0)
  {
    lcd.print(" Mic");
    //lcd.print(version);
  }
  else
  {
   lcd.print("Data");
   //lcd.print(version);
  }
}
if (channel_freq == 1)
{
  if (mode == 1)
  {
    lcd.setCursor(6,0);
  }
  else if ( mode == 0 )
  {
    lcd.setCursor(7,0);
  }
  lcd.blink();
}
else
{
  lcd.noBlink();
}
} // end of updatedisplay()
 
 
void SendFrequency()
 
 
 
 
{
 
if (mode == 1 ) // SSB
 
  {
    si5351.set_freq(((txcio + freq) * 100ULL), SI5351_CLK0);     // VFO
    si5351.set_freq((txcio * 100ULL), SI5351_CLK2);              // BFO
 
  }
 
else if (mode == 0) // CW
 
  if ( tx == 0 )
 
  {
 
    si5351.set_freq(((txcio + freq - cwoffset - filteroffset) * 100ULL), SI5351_CLK0);    // VFO
    si5351.set_freq(((txcio  - filteroffset) * 100ULL), SI5351_CLK2);                     // BFO
 
  }
 
  else if (tx == 1 )
 
  {
 
    si5351.set_freq(((txcio + freq - cwoffset - filteroffset) * 100ULL), SI5351_CLK0);    // VFO
    si5351.set_freq(((txcio - cwoffset - filteroffset) * 100ULL), SI5351_CLK2);           // BFO
 
  }
 
} // end of sendfrequency()

Further Information

Page created : 11/07/26 10:09 BST

Page updated : 01/01/70 01:00 BST

radio, arduino

QRSS MEPT

anonymous@undisclosed.example.com (Anonymous) — Sun, 12 Jul 2026 15:39:55 +0000

←Arduino Projects

QRSS MEPT

I started work on my small QRSS MEPT idea with a simple Arduino / SI5351 / 16×2 LCD arrangement. The LCD is only there because I found this breadboard setup already with Seeeduino Nano, SI5351 and LCD in my box of “Arduino Project bits” - from a previous experiment - and I thought I'd keep it for the time being as a display to help in debugging (?). Once the MEPT is functional and ready for operation I'll remove the LCD (and its code from the sketch)

Step one

modify an old sketch & strip out un-needed code until I had a simple carrier generator
add function to vary the frequency in a stepped-ramp sequence to check operation
add functions to make dits and dahs and spaces of appropriate lengths
add function to send a callsign/message explicitly entered as a series of calls to dah(), dit() and space() and run it from loop()
add code to light an onboard LED during “key-down”
add code to show operating frequency and the letters of the callsign as they're sent on the LCD

I monitored the SI5351 output on my normal 30m grabber - there's enough radiation direct from the SI5351 board to make a trace on the waterfall.

The sketch

Click to read / hide

#include <rgb_lcd.h>
#include <si5351.h>
 
char version[] = "v0.1";
 
 
 
volatile long shift_hz = 0;
int count = 0;
int dit_time = 6000;
 
volatile long freq = 10139780;  //      
 
int digit0 = 0;
int digit1 = 0;
int digit2 = 0;
int digit3 = 0;
int digit4 = 0;   
int digit5 = 0;
int digit6 = 0;
int digit7 = 0;
 
 
 
// Instantiate the Objects
rgb_lcd lcd;
Si5351 si5351;
 
void setup()
{
 
  // Initialize the display
  lcd.begin(16, 2);
 
  lcd.cursor();
 
  // Initialize the Si5351
  si5351.init(SI5351_CRYSTAL_LOAD_8PF, 0, 0);
  si5351.set_correction(-37500, SI5351_PLL_INPUT_XO);
  si5351.set_pll(SI5351_PLL_FIXED, SI5351_PLLA);
  si5351.drive_strength(SI5351_CLK0, SI5351_DRIVE_8MA);
 
  pinMode(13, OUTPUT);
  // Update display and send start frequency
 
    SendFrequency();    
    digit0 = (freq%10);
    digit1 = ((freq/10)%10);
    digit2 = ((freq/100)%10);
    digit3 = ((freq/1000)%10);   
    digit4 = ((freq/10000)%10);
    digit5 = ((freq/100000)%10);
    digit6 = ((freq/1000000)%10);
    digit7 = ((freq/10000000)%10);
 
    UpdateDisplay();
 
}
 
 
void loop()
{
 
// SendRamp();
SendCall();
// SendRamp();
 
}
 
 
void SendCall() {
 
  space();
 
  dah();
  dah();
  dit();
  lcd.setCursor(5,1);
  lcd.print("G");
  space();
 
 
  dah();
  dah();
  lcd.setCursor(6,1);
  lcd.print("M");
  space();
 
 
  dit();
  dit();
  dit();
  dit();
  dah();
  lcd.setCursor(7,1);
  lcd.print("4");
  space();
 
  dit();
  dit();
  dit();
  lcd.setCursor(8,1);
  lcd.print("S");
  space();
 
  dit();
  dah();
  dit();
  dit();
  lcd.setCursor(9,1);
  lcd.print("L");
  space();
 
  dit();
  dit();
  dit();
  dah();
  lcd.setCursor(10,1);
  lcd.print("V");
  space();
 
  space();
 
 
}
 
 
void space() {
  shift_hz = 0;
  SendFrequency();
  delay(dit_time * 2);
}
 
void dah() {
  shift_hz = 4;
  digitalWrite(13, HIGH);
  SendFrequency();
  delay(dit_time * 3);
  shift_hz = 0;
  SendFrequency();
  digitalWrite(13, LOW);
  delay(dit_time);
 
}
 
void dit() {
  shift_hz = 4;
  digitalWrite(13, HIGH);
  SendFrequency();
  delay(dit_time);
  shift_hz = 0;
  SendFrequency();
  digitalWrite(13, LOW);
  delay(dit_time);
 
}
 
void SendRamp() {
 
 shift_hz = 0;
 while ( shift_hz < 6 ) {
  digitalWrite(13, HIGH);
 SendFrequency();
   shift_hz++;
   delay(2000);
   SendFrequency();
 }
   shift_hz = 0;
   SendFrequency(); 
   delay (dit_time * 2);
 
   digitalWrite(13, LOW);
}
 
void UpdateDisplay()
{
 
 
 
  lcd.setCursor(0,0);
  lcd.print(digit7);
  lcd.setCursor(1,0);
  lcd.print(digit6);
  lcd.setCursor(2,0);
  lcd.print(",");
  lcd.setCursor(3,0);
  lcd.print(digit5);
  lcd.setCursor(4,0);
  lcd.print(digit4);
  lcd.setCursor(5,0);
  lcd.print(digit3);
  lcd.setCursor(6,0);
  lcd.print(".");
  lcd.setCursor(7,0);  
  lcd.print(digit2);
  lcd.setCursor(8,0);
  lcd.print(digit1);
  lcd.setCursor(9,0);
  lcd.print(digit0);
  lcd.setCursor(10,0);
  lcd.print("Hz");
 
  lcd.setCursor(0,1);
 
  lcd.print("QRSS");
 
  lcd.setCursor(12,1);
  lcd.print(version);
 
}
 
void SendFrequency()
{
 
  si5351.set_freq(((freq + shift_hz) * 100ULL), SI5351_CLK0);     // VFO
 
}

Step Two

The next step will be to build a small TX PA to boost the SI5351 output up to around 1W and a LPF. I'll add a PTT line to key the PA, driven from the Arduino so that the sketch can have periods of carrier off between cycles if necessary. 1W should be enough power and should be simple enough to generate. I might have a go at a Class-E MOSFET amplifier.

Test Amp

I found a 30m PA strip from a previous project that produces about 6W from < 10mV drive, with 3 class-A bipolar driver stages feeding an IRF510 MOSFET - originally intended as a linear amplifier.

I've played with the supply volts and the MOSFET bias and can comfortably get up to 3W carrier with 8V supply. It's not terribly efficient but at QRP levels that's hardly relevant.

I've got it connected to the Ardiuno/Si5351 and it's on the air running 1W.

I'll use this amp as a blueprint for a new PA for the MEPT, perhaps with fewer stages as I don't need so much gain or linearity.

I've seen it on grabbers around Europe

Grabber results at 1W

At 1533z I reduced power to around 200mW

Grabber Results at 200mW

Stretch Goals

Add a function to generate “Slow FSK Hell” to make waterfall-readable text - see the image of GM4GHK below
Add DFCW
Add a “normal-speed CW ident” for cases where it might make sense (?)

Further Information

Page created : 12/07/26 07:40 BST

Page updated : 01/01/70 01:00 BST

radio, qrss, arduino, mept

Arduino Projects

anonymous@undisclosed.example.com (Anonymous) — Sat, 11 Jul 2026 08:56:28 +0000

←Radio Topics

Arduino Projects

An area for my Radio projects that use an Arduino

Further Information

Page created : 11/07/26 09:54 BST

Page updated : 11/07/26 09:56 BST

radio, arduino