I thought now a days the broadcasting stations put up a brick wall filter at something like 800 or 900 hurts to prevent the public from accidentally picking up stuff like this with their teeth or electrical supplies that are never meant to do this. I can't remember the lecture we had in my class I took on such things and I no longer have all the tapes, but that's the one thing I remember, the brick wall filter that supposedly is on all am and fm transmitters.
take care to all. On Mar 15, 2014, at 8:16 PM, Martin G. McCormick <[email protected]> wrote: > The stories about radio stations being received on > heaters, electric kettles and tooth crowns are not crazy at all > but they are weird all right. > > Here is a very brief simple explanation. Electricity > produces magnetism every time it passes through anything > conductive. It could be electric wire, water with salt water > being the best, you name it. If it conducts, some magnetism > results. > > Ther are also substances like certain ceramics, bones, > teeth and minerals that are said to be piezoelectric which means > they produce electricity when force is applied to them and they > also bend or twist ever so slightly when electric current is > applied. > So, what does this have to do with anything we are > talking about? > Well, everything but you have to think outside the box. > > While telephones, music players and electronic devices > have speakers and buzzers meant to be heard, Your heater or > kettle wasn't ever made to be heard but some of the same > activity that makes a speaker speak goes on accidentally in just > about anything electrical or electronic. How many machines do > you have that make some noise as they work but that's not their > primary function? > The hot wires in an electric heater or cooking appliance are not > too different in some ways than the very fine wire in a coil > that is called the voice coil in loud speakers and headphones. > The voice coil produces magnetism which adds to and subtracts > from a permanent magnet and pushes and pulls a thin diaphragm of > paper or plastic that turns the vibrations in to sound. > In the electric heater or kettle, those wires produce strong > magnetic fields that cause the very wire itself to vibrate > causing a slight humming sound in some devices and occasionally > a fairly loud buzz or hum. > Radio signals from strong nearby AM stations can make it > on to the power mains or lines leading to your house and, if > strong enough, could generate magnetic fields and vibrations > just like a voice coil in a speaker though not well. > Also, some heaters contain a device called a rectifier > or diode that turns alternating current in to direct current for > various technical reasons. This would make it even easier to > hear music on your heater. See the next paragraph. > As for tooth fillings and crowns, etc, we actually have all the > ingredients for a radio in our bodies but fortunately, they > don't work all that well for most of us most of the time. > Teeth and bones are capable of turning electric currents > in to vibrations. The saliva in some people's mouths is acidic > and that combination can rectify the signal of a radio station > like an old-fashioned crystal radio. If you live close enough to > the broadcast antenna, the audio of the radio signal will be > decoded and vibrate your teeth and skull, making you hear sound. > Several years ago, there was a news report about a > veteran of the Vietnam War who had bullet fragments in his skull > and complained of hearing a local radio station. It was > absolutely proved he was telling the truth when another person > could also hear it by pressing his ear to the man's head. > > There is a high-powered AM radio station in South > Oklahoma City and people who live near the antenna can hear it > on lots of odd objects such as a cooking pan with a fork lying > tines-down with a bit of water in the bottom of the pan. > Hearing radio stations where you shouldn't be hearing them > doesn't happen every day, but I hope I haven't bored too many of > you as to what is happening. It has never happened to me as far > as tooth fillings but I have certainly heard my share of > radio stations on amplifiers that weren't properly filtered. > > Martin > > ======================================= > > The Techno-Chat E-Mail forum is guaranteed malware, spyware, Trojan, virus > and worm-free > > To modify your subscription options, please visit for forum's dedicated web > pages located at > http://mail.tft-bbs.co.uk/mailman/listinfo/techno-chat > > You can find an archive of all messages posted to the Techno-Chat group at > either of the following websites: > > http://mail.tft-bbs.co.uk/pipermail/techno-chat/index.html > > Or: > <http://www.mail-archive.com/[email protected]> > you may also subscribe to this list via RSS. 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