The all-digital MA3 signal has been proven reliable out to around the 0.1 mV/m contour, or 100 uV/m (red in the figure). This is 1/5 the strength of the old standard, and merely 5% of the signal level ...

MA3 also relocates the secondary carriers to the upper sideband and the tertiary carriers to the lower sideband, and both have their power increased to –30 dBc. Thus the MA3 mode requires 20 kHz of ...