Setting to smallest bandwidth possible

[pe5pvb]

Hi,

Maybe you guys can help me. I'm building a spectrum monitor for a RF converter and use the RFM69 module to measure RSSI. The only thing I can't find out is what I need to send to set the receiver to the smallest bandwidth possible. This is needed to get the most accurate readout.

My current working testcode is:

Code Select Expand

#include <TFT_eSPI.h>
#include <RFM69.h>                  //get it here: https://www.github.com/lowpowerlab/rfm69
#include <SPI.h>                    //included with Arduino IDE (www.arduino.cc)
#include <analogWrite.h>            // https://github.com/ERROPiX/ESP32_AnalogWrite
#include "ADF4351.h"                // Included with this file
#include <RotaryEncoder.h>          // https://github.com/enjoyneering/RotaryEncoder

#define RFA                   32
#define RFB                   15
#define BANDBUTTON            27
#define BWBUTTON              33
#define ROTARY_BUTTON         39
#define PIN_POT               35
#define ROTARY_PIN_A          36
#define ROTARY_PIN_B          34

unsigned int frequency1 = 43600;
unsigned int frequency2 = 14460;
unsigned int frequency3 = 7100;
unsigned int frequency4 = 5100;
unsigned int frequencyold;
byte bandselect = 1;
byte bwselect = 1;
byte bw1;
byte bw2;
int position = 0;

RFM69 radio;
TFT_eSPI display = TFT_eSPI(176, 220);
RotaryEncoder encoder(ROTARY_PIN_A, ROTARY_PIN_B, ROTARY_BUTTON);
ADF4351 Frontend;

void ICACHE_RAM_ATTR encoderISR() {
  encoder.readAB();
}

void ICACHE_RAM_ATTR encoderButtonISR() {
  encoder.readPushButton();
}

void setup()   {
  pinMode(2, OUTPUT);
  pinMode(5, OUTPUT);
  pinMode(RFA, OUTPUT);
  pinMode(RFB, OUTPUT);
  pinMode(BANDBUTTON, INPUT);
  pinMode(BWBUTTON, INPUT);
  analogWrite(2, 511);
  Serial.begin(115200);
  Frontend.Init(4, 25000000);
  Frontend.Power(1);
  display.begin(0x3C);
  display.init();
  display.setRotation(3);
  display.fillScreen(TFT_BLACK);
  radio.initialize(-1, -1, -1);
  display.drawRect(1, 1, 219, 175, TFT_BLUE);
  showBand();
  display.drawRect(4, 23, 213, 150, TFT_WHITE);
  radio.setLNA(001);
  radio.setMode(RF69_MODE_RX);
  RF(4);
  attachInterrupt(digitalPinToInterrupt(ROTARY_PIN_A),  encoderISR,       CHANGE);
  attachInterrupt(digitalPinToInterrupt(ROTARY_PIN_B),  encoderISR,       CHANGE);
  attachInterrupt(digitalPinToInterrupt(ROTARY_BUTTON), encoderButtonISR, FALLING);
  position = encoder.getPosition();
}

void RF(byte band) {
  char* addon;
  switch (band)
  {
    case 1:
      digitalWrite(RFA, HIGH);  // 6m
      digitalWrite(RFB, HIGH);
      display.setTextColor(TFT_BLACK);
      if (frequencyold % 100 < 10) addon = "0"; else  addon = "";
      display.drawCentreString(String(frequencyold / 100) + "." + addon + String(frequencyold % 100), 110, 2, 4);
      display.setTextColor(TFT_WHITE);
      if (frequency4 % 100 < 10) addon = "0"; else  addon = "";
      display.drawCentreString(String(frequency4 / 100) + "." + addon + String(frequency4 % 100), 110, 2, 4);
      frequencyold = frequency4;
      Frontend.SetFreq(frequency4 + 31500, 0);
      break;
    case 2:
      digitalWrite(RFA, LOW);  // 4m
      digitalWrite(RFB, HIGH);
      display.setTextColor(TFT_BLACK);
      if (frequencyold % 100 < 10) addon = "0"; else  addon = "";
      display.drawCentreString(String(frequencyold / 100) + "." + addon + String(frequencyold % 100), 110, 2, 4);
      display.setTextColor(TFT_WHITE);
      if (frequency3 % 100 < 10) addon = "0"; else  addon = "";
      display.drawCentreString(String(frequency3 / 100) + "." + addon + String(frequency3 % 100), 110, 2, 4);
      frequencyold = frequency3;
      Frontend.SetFreq(frequency3 + 31500, 0);
      break;
    case 3:
      digitalWrite(RFA, HIGH);  // 2m
      digitalWrite(RFB, LOW);
      display.setTextColor(TFT_BLACK);
      if (frequencyold % 100 < 10) addon = "0"; else  addon = "";
      display.drawCentreString(String(frequencyold / 100) + "." + addon + String(frequencyold % 100), 110, 2, 4);
      display.setTextColor(TFT_WHITE);
      if (frequency2 % 100 < 10) addon = "0"; else  addon = "";
      display.drawCentreString(String(frequency2 / 100) + "." + addon + String(frequency2 % 100), 110, 2, 4);
      frequencyold = frequency2;
      Frontend.SetFreq(frequency2 + 31500, 0);
      break;
    case 4:
      digitalWrite(RFA, LOW);  // 70cm
      digitalWrite(RFB, LOW);
      display.setTextColor(TFT_BLACK);
      if (frequencyold % 100 < 10) addon = "0"; else  addon = "";
      display.drawCentreString(String(frequencyold / 100) + "." + addon + String(frequencyold % 100), 110, 2, 4);
      display.setTextColor(TFT_WHITE);
      if (frequency1 % 100 < 10) addon = "0"; else  addon = "";
      display.drawCentreString(String(frequency1 / 100) + "." + addon + String(frequency1 % 100), 110, 2, 4);
      frequencyold = frequency1;
      Frontend.SetFreq(frequency1 - 31500, 0);
      break;
  }
}

void loop() {
  SpectrumView();
  if (digitalRead(BANDBUTTON) == LOW) {
    bandselect++;
    if (bandselect > 4) bandselect = 1;
    RF(bandselect);
    while (digitalRead(BANDBUTTON) == LOW);
  }

  if (digitalRead(BWBUTTON) == LOW) {
    bwselect++;
    if (bwselect > 6) bwselect = 1;
    showBand();
    while (digitalRead(BWBUTTON) == LOW);
  }

  if (position < encoder.getPosition()) KeyUp();
  if (position > encoder.getPosition()) KeyDown();
  if (encoder.getPushButton() == true) ButtonPress();
}

void KeyUp() {
  while (digitalRead(ROTARY_PIN_A) == LOW || digitalRead(ROTARY_PIN_B) == LOW);
  position = encoder.getPosition();
}

void KeyDown() {
  while (digitalRead(ROTARY_PIN_A) == LOW || digitalRead(ROTARY_PIN_B) == LOW);
  position = encoder.getPosition();
}

void ButtonPress() {
  while (digitalRead(ROTARY_BUTTON) == LOW);
}

void showBand() {
  switch (bwselect)
  {
    case 1:
      bw1 = 74;    // Symbolrate 35
      bw2 = 146;
      display.setTextColor(TFT_BLACK);
      display.drawRightString("500ks/s", 50, 8, 1);
      display.setTextColor(TFT_YELLOW);
      display.drawRightString("35ks/s", 50, 8, 1);
      break;
    case 2:
      bw1 = 70;    // Symbolrate 66
      bw2 = 150;
      display.setTextColor(TFT_BLACK);
      display.drawRightString("35ks/s", 50, 8, 1);
      display.setTextColor(TFT_YELLOW);
      display.drawRightString("66ks/s", 50, 8, 1);
      break;
    case 3:
      bw1 = 65;    // Symbolrate 125
      bw2 = 155;
      display.setTextColor(TFT_BLACK);
      display.drawRightString("66ks/s", 50, 8, 1);
      display.setTextColor(TFT_YELLOW);
      display.drawRightString("125ks/s", 50, 8, 1);
      break;
    case 4:
      bw1 = 50;    // Symbolrate 250
      bw2 = 170;
      display.setTextColor(TFT_BLACK);
      display.drawRightString("125ks/s", 50, 8, 1);
      display.setTextColor(TFT_YELLOW);
      display.drawRightString("250ks/s", 50, 8, 1);
      break;
    case 5:
      bw1 = 40;    // Symbolrate 333
      bw2 = 180;
      display.setTextColor(TFT_BLACK);
      display.drawRightString("250ks/s", 50, 8, 1);
      display.setTextColor(TFT_YELLOW);
      display.drawRightString("333ks/s", 50, 8, 1);
      break;
    case 6:
      bw1 = 20;    // Symbolrate 500
      bw2 = 200;
      display.setTextColor(TFT_BLACK);
      display.drawRightString("333ks/s", 50, 8, 1);
      display.setTextColor(TFT_YELLOW);
      display.drawRightString("500ks/s", 50, 8, 1);
      break;
  }
  SpectrumView();
}

void SpectrumView() {
  long scanfreq = 314495000;
  for (uint8_t i = 0; i < 200; i++) {
    scanfreq += 5000;
    radio.setFrequency(scanfreq);
    float level;
    delayMicroseconds(550);
    level = ((radio.readRSSI() + map(analogRead(PIN_POT), 0, 1023, 90, 95)) * 2);
    if (level < 0) level = 0;
    if (level > 146) level = 146;
    display.drawLine(i + 10, 170, i + 10, 170 - int(level), TFT_YELLOW);
    display.drawLine(i + 10, 170 - int(level), i + 10, 24, TFT_BLACK);
    display.drawLine(bw1, 170, bw1, 40, TFT_RED);
    display.drawLine(bw2, 170, bw2, 40, TFT_RED);
    display.drawLine(bw1, 40, bw1 + 10, 30, TFT_RED);
    display.drawLine(bw2, 40, bw2 - 10, 30, TFT_RED);
    display.drawLine(bw1 + 10, 30, bw2 - 10, 30, TFT_RED);
  }
}