The way to measure electromagnetic frequencies is with a huge range of expensive and specific test equipment . It may be as low as 50 Hz actually a lot lower , but you can hear 50 Hz when an unshielded mic cable is close to a mains run through heat infra red , light , UV , radio signals , TV signals , satellite signals , cellphone signals appx 18002200 MHz and beyond . As to what the numbers on an app represent , could be anything , but probably magnetic flux inferred from the compass sensor . They aren ' t important or indicative of much . <| sep |> You stopped watching because the next episode had a connection with Thor Dark World and you were like oh I have to see that film first and then you delayed watching that film , because you heard it wasn ' t that good , and when you maybe finally watched it you were like oh shield wasn ' t that good either from what I remember so you gave up on it . at least . that ' s what happened to me . I think I went back to it in a few months though after I read online it got good , and I had them all recorded on my tv thingy so I was like gotta free up this trash . Now it ' s my favourite show , and yeah , it gets SOOO good , this new season is amazing in my opinion