Passive HF geolocation methods can be used to extract the location of an unknown transmitter in the range of one-hop HF links through a synchronized time difference of arrival (TDoA) network. This paper aims to highlight that a measurement can be qualified with respect to the different parameters available at the reception sites in the context of passive HF geolocation. In particular, a qualified measurement could be used to estimate the transmitter location whereas unqualified measurement could be discarded which, if processed, would result in a totally incorrect estimate of transmitter location. HF receiver design and the installed receiver network to synchronously capture HF radio signals are presented. Measurements from different transmitters are analyzed in terms of different estimated measurement metrics with the purpose of measurement qualification or elimination. Specifically, data reduction is achieved based on the analysis of the estimated TDoA's by exploiting the assumed coherence of collected measurements over time.