In some article you will read that 4kHz is ELF, while the other article you'll read that 4kHz it is VLF. So where is this 4kHz anyway? And what is difference between ELF, ULF and VLF? Each frequency range has a band designator and each range of frequencies behaves differently and performs different functions.

电磁波能量、频率、波长转换关系： E=h u=h\frac {c} {\lambda}\\ E =4.136\times ( u/10^ {15}Hz)\ eV \\ E=1.240 \times (1\mu m/\lambda) \ eV \\ 其中，普朗克常数，光速为 h=6.626 \times 10^ {-27} erg\, s =6.6…

Here we are building the world’s largest repository of publicly available ELF/VLF/LF radio data, which is used to study the physics of lightning, the ionosphere, and the magnetosphere. The mission of WALDO World is to collect, curate and deliver ELF/VLF/LF radio data for scientific use for open public use.

What is ELF/VLF Research? ELF/VLF stands for Extremely Low Frequency and Very Low Frequency, and refers to the range 300 Hz to 30 kHz. We’re talking about radio waves, like the AM/FM signals you get, just at an even lower frequency.

Extremely low frequency (ELF) is the ITU designation [1] for electromagnetic radiation (radio waves) with frequencies from 3 to 30 Hz, and corresponding wavelengths of 100,000 to 10,000 kilometers, respectively. [2][3] In atmospheric science, an alternative definition is usually given, from 3 Hz to 3 kHz. [4][5] In the related magnetosphere scie...

Very low frequency or VLF is the ITU designation [1] [2] for radio frequencies (RF) in the range of 3–30 kHz, corresponding to wavelengths from 100 to 10 km, respectively. The band is also known as the myriameter band or myriameter wave as the wavelengths range from one to ten myriameters (an obsolete metric unit equal to 10 kilometers).

一些医学 同行评审的 期刊文章是指在频率为50hz和50-80hz的“极低频（elf）磁场（mf）”的情况下的elf。 美国国家航空和宇宙航行局等美国政府机构将ELF描述为频率在0到300Hz之间的 非电离辐射 。

2020年10月15日 · VLF: 甚低频“哨声”的动态光谱仪。 LF: 立体波（SWAVES）利用无线电成像来研究日冕物质抛射。 MF: 非定向信标利用中频无线电频率向飞机传送方向信息。改进无定向信标技术。 HF: QuickScat散射测量卫星捕捉地球上的海风模式图像。

2020年4月26日 · 本文详细介绍了对潜通信系统，包括vlf、elf、卫星通信、水声通信、蓝绿激光、中微子、引力波和流星余迹猝发通信等多种方式。 强调了每种通信方式的特点、优势和应用场景，特别提到了量子通信在水下安全通信的潜力。

THE OPEN LAB’s – ELF and VLF frequency Guide By Trond JACOBSEN Version 1.0 - updated 16 November 2001. The target of focus for this ELF and VLF guide, is manmade signals in the range from DC to 30 kHz.