<P> For typical radio applications, it is common to find f (\ displaystyle \ f) measured in units of GHz and d (\ displaystyle \ d) in km, in which case the FSPL equation becomes </P> <Dl> <Dd> FSPL (dB) = 20 log 10 ⁡ (d) + 20 log 10 ⁡ (f) + 92.45 (\ displaystyle \ (\ mbox (FSPL (dB))) = 20 \ log _ (10) (d) + 20 \ log _ (10) (f) + 92.45) </Dd> </Dl> <Dd> FSPL (dB) = 20 log 10 ⁡ (d) + 20 log 10 ⁡ (f) + 92.45 (\ displaystyle \ (\ mbox (FSPL (dB))) = 20 \ log _ (10) (d) + 20 \ log _ (10) (f) + 92.45) </Dd> <P> For d, f (\ displaystyle \ d, f) in meters and kilohertz, respectively, the constant becomes − 87.55 (\ displaystyle \ - 87.55). </P>

Difference between free space loss and path loss