A mobile base station in an urban environment has a power measurementr of 25 µW at 225 m

Question

A mobile base station in an urban environment has a power measurementr of 25 µW at 225 m. If the propagation follows an inverse 4^th-power law, assuming a distance of 0.9 km from the base station, what would be a reasonable power value, in µW?

Answer 1

You need to devise an equation that relates power and distance in the manner that the question described. An inverse 4th power law.

Power = K / distance ^4

At 25 uW, we can solve for constant K. 25 uW = k/225m^4 = k = (225m^4)x(25uW)

Now we can solve for power at a different distance, 0.9 km or 900 meters.

P = K/d^4 = (225m^4)x(25uW) / 900m^4

P = 0.098 uW

Good luck!