Longley-Rice model works correct in given frequency ranges, antenna heights, distance, surface refraction, as shown in Table 93.
Table 93: Range of ITM model correctly working
Parameter | Range |
Frequency | 20 MHz – 40 GHz |
Antenna height | 50[A1] [A1]This should be 50 cm (or 0.5 m). All the references about the ITM model give 0.5 m as the lower antenna height. For example, J. S. Seybold, "Introduction to RF Propagation," Wiley, 2005.
cm – 3 km |
Distance | 1 – 2 000 km |
Surface refraction | 250 -400 N |