Dados: d = 5 m; c = 3  108 m/s; log 4π = 1,1; log 2 = 0,3; Prec(dB) = 4 dBW; f = 300 MHz = 3  102  106 Hz = 3  108 Hz. Prec(dB) = 10log Prec(...

Dados: d = 5 m; c = 3  108 m/s; log 4π = 1,1; log 2 = 0,3; Prec(dB) = 4 dBW; f = 300 MHz

= 3  102  106 Hz = 3  108 Hz.

Prec(dB) = 10log Prec(W)

10log Prec(W) = 4

Ptra / Prec = ( 4πfd / c )2

= ( 4π 3 108 5 / 3 108 )2

Ptra / Prec = (4π  5)2

10log ( Ptra / Prec ) = 10log (4π  5)2

10log Ptra – 4 = 20  1,8

10log Ptra – 4 = 36

10log ( Ptra / Prec ) = 10log (4 π 10 / 2 )2

10log Ptra – 10log Prec = 2  10log (4 π 10 / 2 )

10log Ptra – 4 = 20  (log 4π + log 10 – log 2)

log Ptra = 40 / 10

log Ptra = 4

Ptra = 104 W

Resp.: Alternativa D.


a) 102 W.
b) 103 W.
c) 105 W.
d) 104 W.
e) 101 W.