## 3 Analysis of Results and Discussion  
During the study, 530 experimental attempts were performed and processed, 222 of which were performed using the first experimental scheme, and 308 using the second. The processed experimental results showed that the characteristics of the current pulse of the upward streamer corona with model rods and elongated elements depended on the characteristics of the electric field (group of amplification coefficient) near such objects (Tables 1 and 2). The impulse current of the streamer flash from the model elements with relatively low amplification coefficients (group I) showed average higher current amplitudes and charges, and less impulse duration. However, higher values of the maximal current rise velocity were observed for the model elements with amplification coefficients ranging from 10 to 25 (group II). For all groups of model amplification coefficients, the duration of the current impulse and flowing charge was on average higher for elongated model elements than for rods. It should be noted that for all groups of model element amplification coefficients, the characteristics of the signals induced in the elongated model elements by the neighboring upward streamer corona flash showed higher values than those of the rod model elements (Table 3). \begin{table}
\begin{tabular}{c c c c} \hline
**Amplification Coefficient** & **Group I** & **Group II** & **Group III** \\ \hline Current amplitude, A & 8.45 & 5.11 & 3.26 \\ Maximal current rise velocity, A/ns & 0.13 & 0.17 & 0.14 \\ Impulse duration, \(\upmu\)s & 2.65 & 5.24 & 2.98 \\ Flowing charge, \(\upmu\)C & 4.38 & 4.17 & 1.96 \\ \hline \end{tabular}
\end{table} 
Table 1: Characteristics of the current impulse of streamer corona on the rod model elements (average values). Figure 7: Wavelet spectrum of the signal induced in the nearby model element by the upward streamer corona flash. The wavelet analysis showed that the spectral characteristics (upper frequency and frequency corresponding to maximal intensity) of a current impulse of an upward streamer flash had average values 1.5-9.0 times higher for the case of the rod model elements than for elongated elements for all the groups of model amplification coefficients (Tables 4 and 5). In some cases, an upper frequency ranging from 500 MHz to 1 GHz appeared in the wavelet spectrum of the current impulse of the streamer corona from the rod model elements related to group III (a higher amplification coefficient). A generalization of the spectral characteristics of the signals induced by the electromagnetic radiation of the nearby impulse streamer corona flash on model elements of different types showed the close values of all frequency parameters inside every group of the electric amplification coefficient for rod and elongated model elements (Tables 6 and 7). The maximal values of the upper level of the characteristic frequency in the wavelet spectrum of the induced signal (the electromagnetic radiation of upward streamers was sometimes in the range of 1.0-1.5 GHz) were discovered in group II (an amplification coefficient of 10-25). Group III (amplification coefficient > 25) showed similar, but slightly lower, values. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Amplification Coefficient** & **Group I** & **Group II** & **Group III** \\ \hline Upper level of the characteristic frequency, MHz & 9.9 & 13.2 & 83.5 \\ Frequency of the maximal intensity, MHz & 0.9 & 1.1 & 5.8 \\ Maximal intensity, A2 & 2300 & 900 & 450 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Spectral characteristics of the current impulse of streamer corona on the rod model elements (average values). \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Amplification Coefficient** & **Group I** & **Group II** & **Group III** \\ \hline Current amplitude, A & 8.89 & 3.04 & 2.19 \\ Maximal current rise velocity, A/ns & 0.10 & 0.13 & 0.12 \\ Impulse duration, \(\mu\)s & 4.12 & 7.08 & 9.23 \\ Flowing charge, \(\mu\)C & 6.54 & 5.09 & 4.12 \\ \hline \hline \end{tabular}
\end{table}