A 10-year data set of alpha and gamma radiation from radon in air has been collected using an Enhanced Confined Mode experiment (ECM; EXP #1). Analysis of periodic phenomena from annual to sub-daily scales of the variation of nuclear radiation from radon reveals: a) Possible multi-year variations; b) Periodic signals which occur in the annual, solar rotation (around 30 days), and daily frequency bands; c) Semi-annual and ternary-annual variations which occur as multiples of the primary annual periodicity; d) Daily variation of 24-hour periodicity which is accompanied by multiples of 12- and 8-hours; e) Non-linear couplings among the annual, solar rotation and daily periodicities; f) Evidence of directionality in the gamma radiation. The setting of EXP #1 is at an above surface outdoor location which is thus subject to large environmental influences. However, the most significant statistical features cannot be attributed to local environmental influences, although there is some similarity in the time domain. The patterns of fundamental geophysical periodicities on annual to daily scales and their modulation by Earth’s rotation around its axis, support the suggestion of an non-terrestrial influence, essentially of solar origin. Further investigations of radon decays in the geo-sphere will allow formulation of new geophysical implications.