...
b = min(0, 20log(Hb/30)) (Eq. 205214)
to be replaced in Hata-SRD model by :
b = ( 1.1 log( f ) - 0.7 ) * min(10, Hb ) - ( 1.56 log(f ) - 0.8 ) + max( 0, 20 log( Hb / 10 ) ); (Eq. 206215)
Note: This expression assumes that antenna heights should not exceed 1.5-3 m.