# Calculations

 e.i.r.p. = P_(TX)  – b + G_(TX) [dBm; dBm, dB, dBi] e.r.p. = e.i.r.p.  – 2,15 [dBm; dBm] G_(dBd) = G_(dBi) - 2,15 [dBd; dBi] P_(TX__W) = 10^((P_(TX__dBm) – 30)/10) [W; dBm] E_(dBµV//m) = e.i.r.p. – 20 * log_10 d + 44,8 [dBµV/m; dBm, km] E_(V//m) = (10^((E_(dBµV//m))/20)) / 10^6 [V/m; dBµV/m] pfddBW/m2 = E_(dBµV//m) – 145,8 [dBW/m2; dBµV/m] pfdW/m2 = E_(V//m)^2 / 377 [W/m2; V/m] P_(RX) = e.i.r.p. – l + G_(RX) – b_(RX) [dBm; dBm, dB, dBi, dB] P_(dBW) = 10 * log_10 P_W [dBW; W] P_(dBm) = P_(dBW) + 30 [dBm; dBW]

 AF75 = 20 * log_10 f - 31,53 - G [dB/m; MHz, dBi] AF50 = 20 * log_10 f - 29,77 - G [dB/m; MHz, dBi] U_(RX) = E - b - AF [dbµV; dBµV/m, dB, dB/m] P_(m50) = U_(RX) - 107 [dBm; dBµV] P_(m75) = U_(RX) - 108,75 [dBm; dBµV]

## Parabolic antenna

G_(dB) = 20 * log_10(f * D) + 10 * log_10 η − 39,6
[dB; MHz, m, —]   Pozn.: dB se číselně shoduje s dBi

## Fresnel zone

 r_n = 17,3 * sqrt((n * d_1 * d_2)/((d_1 + d_2) * f) [m; km, GHz]

## Atmosphere attenuation

 l_(atm) = l_(spec__atm) * d [dB; dB/km, km]