Quote:
Now explenation for Realtek 888 889 .. etc..
That's good soundcard. but, can happen that power supply is not good, motherboard (because motherboard design) etc..
If you load any preset (like yours) and play it via VAC to MPX Tool, you will not see ANY peek after 75kHz. However analog exciters just cannot have same exact 75kHz .. but can be very close.
Few days ago i measured mine transmitter with some professional unit and deviation was 75.5kHz with peeks upto 76.5kHz.
Soundcard is Juli@ and tilt adjusted. (FM Transmitter Calibration)
So, in your case problem can be, Soundcard tilt (?), (power supply, motherboard..), cable or exciter.
There is maybe explenation why beta79 is better for you. now bass is more 'sqere' and if you have tilt on soundcard or transmitter deviation can go high.
my condition is not the final situation beacause in october the computer send the signal MPX to a radio link and now it's a simple cable go to pc to the transmitter