May I stir it up a bit?
The SAA is a bit of concern to LEO satellites -- including the ISS -- because the bottom of a "radiation bubble" dips down into that area, thus its name. It is a region or volume where the frequency of Single Event Effects on Integrated Circuits is slightly higher than other points at that altitude. Or, conversely, matches the frequency of upsets that you would expect at a slightly higher altitude.
The "bubble" bottom and overall volume (roughly donut shaped) I speak of are part of the lower Van Allen radiation belt and of course is related to the ionosphere that influences our terrestrial radio wave propagation. But, my best guess is that on a global scale, the bubble bottom has negligible effect if any at all on signals NOT passing through that particular volume, and likely little affect on signals through that volume. I've made contact with McMurdo station several times but not enough to notice any SAA effects that I know of. I am interested in such observations by others.
My contribution to this discussion is limited to helping describe how the SAA volume is only a small part of a much larger volume(s) surrounding our planet. FWIW, I work with electronics that pass through the SAA on a regular basis, and have also done simulations and testing on ICs w.r.t. SEE/SEU bit flips, latch up and related phenomena. And I still enjoy HF ops to boot.