  We present quantum oscillation measurements of YbRh2Si2 at magnetic fields
above the Kondo-suppression scale H0 ~ 10 T. Comparison with electronic
structure calculations is complicated because the "small" Fermi surface, where
the Yb 4f-quasi-hole is not contributing to the Fermi volume, and "large" Fermi
surface, where the Yb 4f-quasi-hole is contributing to the Fermi volume, are
related by a rigid Fermi energy shift. This means that spin-split branches of
the large Fermi surface can look like unsplit branches of the small surface,
and vice-versa. Thus, although the high-field angle dependence of the
experimentally-measured oscillation frequencies most resembles the electronic
structure prediction for the small Fermi surface, this may instead be a branch
of the spin-split large Fermi surface.
