I should have read your comments better. I'm curious what is the RF meter you're using that shows the exact frequency range of the signal? I have an HF35C and Safe & Sound Pro II which only indicate the strength of the signal in (micro)uw/m2 in the range of 200 Mhz - 12 Ghz. Your measurements are in milliwatts per m2 correct? It gets confusing.
I have measured RF on both of my meters from lights which are on dimmer switches when turned on and also from lights which are on an incorrectly wired electrical circuit. Dirty electricity can be heard with a cheap AM battery operated radio coming from keyboard, mouse, computer screen and many other electrical devices. In the US, dirty electricity is a multiple of 60 hertz, i.e, 120 Hz, 180, 240, and up. In Europe it would be multiples of 50 Hz.
This site indicates that RF range for submarines is as low as 30 hertz!