Amateur ULF: 5 wavelengths on the 101km band?

From Stefan DK7FC:

Hi all,

Meanwhile my 1 week taking transmission, starting  01.FEB.2017 23:30 UTC on 2970.000000 Hz at 150...170 mA is completed. I tried to leave a trace/peak into a range beyong 3 wavelengths.

Renato Romero / IK1QFK is running a 5 uHz FFT spectrogram on 2970 Hz. He's using a well working E field antenna in Cumiana/Italy.
The spectrogram is running since christmas evening 2016, available at http://www.webalice.it/rromero/live_cumiana/last-LFtest_2970.jpg

There are time markers in 1 week intervals.

I can see a dash, a trace right on the frequency. It appeared 2 days after i started transmitting, which is expected with an FFT window time of nearly 3 days. The SNR was up to 12 dB during the visual observation of incoming spectra.
Partly, the trace disappered during the transmission time (destructive interference with QRN). However i can see a resulting trace of a high average SNR and exact (!) frequency stability relative to the other traces beeing present in the spectrogram.

I would tend to call it a serious detection of my signal. Spectrogram experts, what's your opinion please?

The distance is quite exactly at 5 wavelength on that 101 km band!
It would be a first detection on ULF (0.3...3 kHz) between DL - I !

73, Stefan