Upon further investigation, the BFO value from the hw_settings.ini file is used.? Look in sbitx.c around line 903?
/*?
This is the one-time initialization code?
*/
void setup(){
?
read_hw_ini();
?
//setup the LPF and the gpio pins
pinMode(TX_LINE, OUTPUT);
pinMode(TX_POWER, OUTPUT);
pinMode(LPF_A, OUTPUT);
pinMode(LPF_B, OUTPUT);
pinMode(LPF_C, OUTPUT);
pinMode(LPF_D, OUTPUT);
? digitalWrite(LPF_A, LOW);
? digitalWrite(LPF_B, LOW);
? digitalWrite(LPF_C, LOW);
? digitalWrite(LPF_D, LOW);
digitalWrite(TX_LINE, LOW);
digitalWrite(TX_POWER, LOW);
?
fft_init();
vfo_init_phase_table();
? setup_oscillators();
read_hw_ini is performed before setup_oscillators.? The initial value would be overwritten.
I believe that the BFO impacts the frequency used, so it could be used to calibrate.? The potential issue is misalignment with the 40MHz crystal filter.? Since the bandwidth is 25kHz, this should have minimal impact.? Again, I do not have access to my sbitx to validate.
73
Evan
AC9TU
