<https://lh3.googleusercontent.com/-LYasQnPTuZw/VbqhztDFUnI/AAAAAAAAABM/Krolxv4oHR4/s1600/world.JPG> The world is divided roughly into two parts, one part subjected to a 50 cycle per second mains and one part subjected to a 60 cycle per second mains.
As all my measurements have been made in the UK the Hum detectors I use have been tuned to 50 c/s. It has long been observed that the Hum is nothing like a pure tone, it is more like a rumbling with a mixture of frequencies. In an attempt to separate these frequencies I have constructed Hum detectors tuned to various frequencies and have found two dominant frequencies one at 50 c/s and one at 60 c/s. It may at first seem improbable but it appears possible to detect Hum waves in the UK that originate in the USA, this being the closest source of a 60 c/s grid. One striking feature is that the intensity of the 60 c/s waves increase during the hours of darkness, this is also when the Hum is loudest and most obtrusive. It appears that at such times the brain is subjected to both frequencies and most probably the difference frequency of 10 cycles per second, such a low frequency would account for the rumbling sensation. -- You received this message because you are subscribed to the Google Groups "Hum Sufferers" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/hum-sufferers. For more options, visit https://groups.google.com/d/optout.
