the foregrounds, which depend on frequency. Here, we show the frequency dependence of the MWA data.]{}

Fig. \[fig:APSfreq\] shows the APS calculated from visibility data with 1.28MHz bandwidth in units of $\rm Jy^2$. At small scale ($l>200$), the signal increases with decreasing frequency, and the APS at 167MHz is 1.53 times larger than the signal at 197MHz. This feature is consistent with the negative spectral index of point source foregrounds [e.g., @2017MNRAS.464.1146H]. On the other hand, at large scales, the several APSs at high frequencies are stronger than that of low frequency data. As discussed above, the APS is dominated by the Galactic synchrotron emission with the negative spectral index at these scale, and therefore this feature is un-expected. This feature is caused from the pointing dependence of APS as shown in Fig. \[fig:APSLST\].

[Frequency dependence of the CPS is shown in the Fig. \[fig:CPSfreq\]. No clear tendency can be seen in the behavior of the CPS. However, the CPS is dominated by foreground error, as indicated in the above analysis (e.g. Fig. \[fig:IonoX\] and Fig. \[fig:CPSLST\]). Thus, Fig. \[fig:CPSfreq\] indicates that the frequency dependence is weaker than the variance due to foreground errors. ]{}[However, the CPS shows weak oscillation 