\begin{table}%[!h]%T2
%\renewcommand{\arraystretch}{1.05}
%\centering
\par
\caption{Main properties of the selected dm radio spikes shorter
than 100~ms observed in three events on 11 July 2000. The drifts
in frequency were calculated for spikes with inclined dynamic
spectra only, vertical spectra were considered as having
non-measurable drifts.}\label{t2}
\begin{tabular}{lrrr}
\hline \hline& \multicolumn{3}{c}{11 July 2000} \\
\cline{2-4} & \multicolumn{1}{c}{12:30:10--13:30:10} &
\multicolumn{1}{c}{14:34:50--14:51:30} & \multicolumn{1}{c}{14:57:40--15:02:20} \\
\hline 
No. of spikes           & 826 & 237 & 340 \\
No. spikes $<$100~ms     & 808 & 237 & 338 \\
Duration (s) &&&\\
min/max & 0.011/0.99 &0.012/0.097 & 0.009/0.085 \\
mean/median (skew.)  & 0.033/0.027 (1.7) & 0.025/0.019 (2.1) & 0.022/0.017 (2.5) \\
Width (MHz): &&&\\
min/max & 3.1/31.4 & 3.9/25.6 & 3.1/30.7 \\
mean/median (skew.)  & 10.1/9.1 (1.1) & 13.57/13.4 (0.3) & 9.09/8.2 (1.4) \\
Relative width (\%) &&&\\
min/max & 0.22/2.16 & 0.28/1.77 & 0.21/2.24 \\
mean/median (skew.)  & 0.71/0.65 (1.1) & 0.96/0.93 (0.3) & 0.64/0.57 (1.4) \\
Negative drifts (MHz/s) &&&\\
No. spikes   & 140 &32 & 40 \\
min/max & 64/3850 & 330/2952 & 254/2622 \\
mean/median (skew.) & 1105/799 (0.9) & 1467/1512 (0.0) & 1160/1058 (0.4) \\
Positive drifts (MHz/s) &&&\\
No. spikes & 105 & 36 & 38 \\
min/max      & 142/3853 & 373/5155 & 144/2423 \\
mean/median (skew.)  & 1174/966 (1.1) & 1695/1680 (1.2) & 894/672 (0.9) \\
\hline
\end{tabular}
\end{table}