Horizontal symmetry and mass of the $t$ quark

We estimate masses of the $b$ and $t$ quarks as $m_b=4-6\mathrm{}$ GeV and $m_t=16-19\mathrm{}$ GeV, assuming the horizontal gauge symmetry, $\mathrm{S}{\mathrm{U}}_F\mathrm{}\left(3\right)\mathrm{}$.