I tried using the iOS app to check the tension on my Gates Carbon Drive belt (centre-track, CDX I assume as it's driving a Rohlof) and I could not get a consistent measurement over the length of the belt. It varied between 35Hz and ~70Hz.
How is this possible?*
Is the belt ruined?
Is this what is causing the belt to make horrible noises and the spokes of my rear wheel to loosen, such that I've had to go around and tighten them three times within the space of a week?
[*] Might it be caused by "rolling the belt on" to the sprocket in direct contradiction to the Gates manual which says "don't do that" (pages 4, 16, 17)?