Observed radio SED of NGC 7027 (Zijlstra et al. 2008) over the same period of time as the time baseline covered here. All the Effelsberg frequencies from 2.64 up to the highest IRAM frequency of 142.33 GHz are shown. The filled circles (red and black) denote the measurements. The red symbols mark the Effelsberg measurements that where used in the fit, the red dotted-dashed line is the fitted spectrum. The grey area denotes the 1σ region around each data point. The agreement of the extrapolated values with those measured by IRAM is better than 3%.