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The BRITE Constellation of nanosatellites obtained mmag photometry of 28Cygni for 11 months in 2014-2016. Observations with the Solar Mass EjectionImager in 2003-2010 and 118 H$\alpha$ line profiles were added.  For decades, 28 Cyg has exhibited four large-amplitude frequencies: twoclosely spaced frequencies of spectroscopically confirmed $g$ modes near 1.5c/d, one slightly lower exophotospheric (Stefl) frequency, and at 0.05 c/d thedifference frequency between the two g modes. This top-level framework isindistinguishable from eta Cen (Paper I), which is also very similar inspectral type, rotation rate, and viewing angle. The Stefl frequency is theonly one that does not seem to be affected by the difference frequency. Theamplitude of the latter undergoes large variations; around maximum the amountof near-circumstellar matter is increased, and the amplitude of the Steflfrequency grows by some factor. During such brightenings dozens of transientspikes appear in the frequency spectrum, concentrated in three groups. Onlyeleven frequencies were common to all years of BRITE observations.  Be stars seem to be controlled by several coupled clocks, most of which arenot very regular on timescales of weeks to months but function for decades. Thecombination of g modes to the low difference frequency and/or the atmosphericresponse to it appears significantly nonlinear. Like in eta Cen, thedifference-frequency variability seems the main responsible for the modulationof the star-to-disc mass transfer in 28 Cyg. A hierarchical set of differencefrequencies may reach the longest timescales known of the Be phenomenon.

Short-term variability and mass loss in Be stars III. BRITE and SMEI satellite photometry of 28 Cygni