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The expression of b(Hb) parameter in the Extended Hata model, giving large extra losses for transmitter antenna heights below 30 m, was considered to be unnecessarily severe. Therefore, the only difference between Extended Hata-SRD and Extended Hata model lies in the new expression for the antenna gain factor b(Hb), which for Extended Hata model is expressed as
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| body | b = min(0, 20log(Hb/30)) |
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(Eq. 214)
to be replaced in Hata-SRD model by :
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| body | b = ( 1.1 log( f ) - 0.7 ) * min(10, Hb ) |
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| - ( 1.56 log(f ) - 0.8 ) + max( 0, 20 log( Hb / 10 ) ) |
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;
(Eq. 215)
Note: This expression assumes that antenna heights should not exceed 1.5-3 m.