Re: #uBITX Firmware KD8CEC - IF-Shift etc. #ubitx

Ian Lee


I programmed something similar to what you said. I just added another setting instead of a constant(SECOND_OSC_USB).

The code is shown below.

    if (isUSB){
      si5351bx_setfreq(2, SECOND_OSC_USB - usbCarrier + f  + (isIFShift ? ifShiftValue : 0));
      si5351bx_setfreq(1, SECOND_OSC_USB);
      si5351bx_setfreq(2, SECOND_OSC_LSB + usbCarrier + f + (isIFShift ? ifShiftValue : 0));
      si5351bx_setfreq(1, SECOND_OSC_LSB);

Also, I would like to ask you an opinion, but now I am using the hotspot in the place where the internet is not available, so I can not use it long. 

I temporarily shifted the usbCarrier (BFO Setting value) when IF-Shift was applied.
I thought IF-Shift was a temporary function that only used for a while, so I could not satisfy both LSB and USB.
The IF-Shift value can be set to + or -, so can set the desired value according to the using mode.


2018-03-11 5:54 GMT+09:00 Jerry Gaffke via Groups.Io <jgaffke@...>:

I think I was wrong in my previous post, shifting the value of SECOND_OSC_USB won't help.
The audio frequencies through the crystal filter should be strictly a matter of where the BFO is relative to 
the crystal filter passband.  I can't explain why USB audio would be different than LSB audio.

I'm not quite sure what you mean by "IF Shift function".
Can you give an example?


On Sat, Mar 10, 2018 at 11:59 am, Mike Woods wrote:
The IF Shift function should only be applied during RX, but it sounds like it is being applied during TX in error in KD8CEC's sketch.  Probably a bug.

However, the op shouldn't be using the IF Shift permanently, he may not have used the BFO calibration function to fix the shift for LSB & USB for the correct passband.

Best 73
KD8CEC / Ph.D ian lee
kd8cec@... (my blog)

Join to automatically receive all group messages.