These readings were taken inside the Russian B-39 submarine at the San Diego Maritime Museum. If you live in that area and are wondering whether being shielded from certain frequencies will help you, this is a fairly cheap way to find out ($18).
(I haven't determined yet why the images appear horizontal here. They were vertical in my image viewer and in Google Photos.)
If you use a low backlight setting on your display and can't read them, here they are: -60 dBm (the lowest level the Cornet meter will display) and 0.02 uT (on the Cornet's LF30 mode, which only goes up to 1KHz).
The sub had CFL and LED lights, but so I was surprised that the first reading was so low.