  The relativistic string Hamiltonian is used to calculate the masses and decay
constants of $B_q$ mesons: they appear to be expressed through onlythree
fundamental values: the string tension $\sigma $, $\alpha_s$, and the quark
pole masses. The values $f_B =186 $ MeV, $f_{B_s}= 222$ MeV are calculated
while $f_{B_c}$ depends on the $c$-quark pole mass used, namely $f_{B_c}=440
(424)$ MeV for $m_c =1.40 (1.35)$ GeV. For the $1P$ states we predict the
spin-averaged masses: $\bar M(B_J)=5730$ MeV and $\bar M(B_{sJ})=5830$ MeV
which are in good agreement with the recent data of the D0 and CDF
Collaborations, at the same time owning to the string correction being by $\sim
50$ MeV smaller than in other calculations.
