Emitters are limited to a preset list. Emitter frequencies are nominal frequencies. Intercept ranges of zero indicate that this nominal frequency does not fall within the prescribed receiver s bandwidth. . The ESM program does not account for absorption of EM energy. In general, the absorption of EM energy by things such as oxygen, water vapor, fog, rain, or snow adds little to the propagation loss.
Refraction is considered the main factor in transmission. .
The ESM program is valid for frequencies between 100 Mhz and 20 GHz. . Sea-reflected interference is considered. . Errors are small and should be insignificant when the separation exceeds a few thousand feet. . The effects of a surface-based evaporation duct. The ESM program assumes the emitters are radiating at peak power. .