How the ELF-VLF background noise spectrum looks like?

In the ELF-VLF frequency band,some background noise like Schumann resonances shows in the spectrum analyzer as peaks.

I want to have a overview look of the background noise of ELF-VLF frequency band,but have no spectrum analyzer and antenna which can analyze ELF-VLF signal,and I googled but has no expected result.

How the ELF-VLF background noise spectrum looks like?

• how would you even observe that spectrum? You literally can't do that without a nation-sized antenna. Sep 29 '21 at 10:21
• An antenna can either be small, and highly tuned for a narrow bandwidth, or it can be wideband and large. "large" in terms of wavelengths, which I leave up to you to calculate. Now, when you say you want to observe background noise, you'll need an antenna that is wideband AND known and constant in gain. That's a nation-level research institute problem. Sep 29 '21 at 12:27
• So, while your question is indeed an interesting one, it bears the question of "what is it that you actually need to observe", because no matter what you observe, you'll never see that background spectrum. Sep 29 '21 at 12:28
• (downvote for lack of research, by the way, the wikipedia article on Schumann resonances actually describes the measurement method & effort. ) Sep 29 '21 at 12:38
• @MarcusMüller,searched again and again,there's no one picture to show an overview of natural background spectrum Oct 5 '21 at 17:35