One of the most commonly used parameters to describe seismic attenuation is the high‐frequency spectral decay parameter Kappa (), yet the physics behind it remain little understood. A better understanding of potential factors that lead to large scatter in estimated values of constitutes a critical need for ground‐motion modeling and seismic hazard assessment at large. Most research efforts to date have focused on studying the site‐to‐site and model‐to‐model variability of , but the uncertainties in individual estimations associated with different events at a selected site (which we refer to as the within‐station variability of ) remain uncharacterized. As a direct corollary, obtaining robust estimates of the site‐specific component , and their corresponding interpretation become a challenge. To understand the sources of the variability observed in (and ) at a single site, we select 10 Japanese Kiban–Kyoshin network (KiK‐net) downhole arrays and investigate the systematic contributions from ground‐motion directionality. We observe that estimated from a single horizontal component is orientation dependent. In addition, the influence of ground‐motion directionality is a function of local site conditions. We propose an orientation‐independent ‐value, which is not affected either by ground‐motion directionality or by the events’ azimuths. In addition, we find that focal depth of events used in calculations affects the estimation of the regional attenuation component , which, in turn, influences the within‐station variability in the model.