Results from a recent measurement campaign in Turkey, pertinent to reliability and compatibility determination in HF service planning, are presented. Within-an-hour signal fading was found to be slightly more severe than, but day-to-day variability only half as large as the values (in decibels) adopted by the 1984 World Administrative Radio Conference on HF Broadcasting, or WARC-HFBC(84). Within-an-hour variability of noise was negligible, and day-to-day variations of noise were only about one quarter of the amplitude (in decibels) given by CCIR report 322-3 [International Radio Consultative Committee (CCIR), 1988a]. The day-to-day spatial correlation coefficients of both signal and noise at sites separated in range by about 400 km were found to be about 0.4. Correlation of signal with noise at each site was negligible.