  Processes with almost periodic covariance functions have spectral mass on
lines parallel to the diagonal in the two-dimensional spectral plane. Methods
have been given for estimation of spectral mass on the lines of spectral
concentration if the locations of the lines are known. Here methods for
estimating the intercepts of the lines of spectral concentration in the
Gaussian case are given under appropriate conditions. The methods determine
rates of convergence sufficiently fast as the sample size $n\to\infty$ so that
the spectral estimation on the estimated lines can then proceed effectively.
This task involves bounding the maximum of an interesting class of non-Gaussian
possibly nonstationary processes.
