Branch contents in sparsely short-chain branched polyethylenes (<C28) and end-group concentrations in linear polyethylenes were investigated by solid- and melt-state 13C NMR using model copolymers of 1-octene, 1-octadecene, 1-hexacosene, and linear PE standards. Benchmark measurements were established for single-pulse acquisition under MAS on these melts at 423 K, using 7 mm ceramic rotors and commercially available solid-state probes at 300 and 500 MHz 1H Larmor frequency. Signal improvement by a factor of 3−4 was observed, corresponding to a factor 10 reduction in measurement time, when compared to a reference solution-state (400 MHz 1H) measurement. Transient NOE effects due to proton decoupling during FID acquisition were found to affect significantly the accuracy of branch content determination and end-group analysis in the melt spectra, even at moderate pulse repetition rates. 13C T1 and NOE buildup rates and intensity variations were established at 423 K and correlated to the local packing of the b...