Výpočty

Rádiový spoj

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]

Vstup přijímače

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]

Parabolická anténa

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

Fresnelova zóna

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

Útlum atmosféry

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