Is it the Code, the Hardware or my Ignorance?

Projects Programming
2

The code looks reasonable to me. You should set the ch_1 and ch_2 pins to INPUT but that's the default.

I would print to Serial the values of 'x' and 'y' just after the calls to pulseIn() to make sure you are getting the expected values between 1000 and 2000.

// receiver pins and arduino pins
const int ch_1 = 10; // receiver pin 1 (L&R) arduino pin 10
const int ch_2 = 11; // receiver pin 2 (F&B) arduino pin 11

void setup()
{
  Serial.begin(115200);
  delay(200);

  pinMode(ch_1, INPUT);
  pinMode(ch_2, INPUT);
}

void loop()
{
  // Read pulse width from receiver
  int x = pulseIn(ch_1, HIGH, 30000);
  int y = pulseIn(ch_2, HIGH, 30000);

  Serial.print(x);
  Serial.print(' ');
  Serial.println(y);

  delay(2000);
}

If you are NOT getting a value of 1000 to 2000 for both channels every time then it's time to worry about hardware.