\begin{table}%t1
%\centering
\par
\caption {\label{tab:1657}Fluxes determined for the phase-reference 1657-56.}
\begin{tabular}{llllll}
\hline\hline
& Config.& 8.6~GHz & 4.8~GHz & 2.5~GHz & 1.4~GHz \\
& &(Jy)& (Jy)& (Jy)& (Jy)\\
\par
\hline
1998 Mar. & 6B & $1.54$ & $1.81$ & $1.92$ & $1.89$ \\
2001 Jun. & 750C & $1.44$ & $1.61$ & $1.71$ & $1.88$ \\
2002 May & 6A & $1.63$ & $1.79$ & &\\
\hline
\end{tabular}
\end{table}