On Fri, 4 Aug 2000 01:42:26 -0700, davidmeigs
<[log in to unmask]>:

>Also you said that the PD surgeries use radio waves, can this be explained
>to someone like me with zilch techno background. Are you aware of a link
>that talks about the "how" these operations work? I thought they used
>electrical current, not radio waves. Is that why people can tell if their
>device is on by placing a radio next to the device to tell them if it is on?

I'll leave the medical applications to the physicians but radio waves
are electrical energy.

All electrical devices in which current flows are emitters of
electromagnetic energy fields. A radio receiver can often pick up
signals from some of these if the field is alternating (oscillating),
for instance, the wiring in your house. Sometimes a compass can pick
up the emissions if are steady state, for instance the current from a
battery.

Oversimplifying, radio waves are similar to the current (alternating
current- AC) in your home in which the current reverses it's direction
of flow 60 times per second, except that the direction of the radio
wave's current flow changes at a much higher rate. The numbers on your
radio usually represent the number of times the radio waves change
direction. On an ordinary home or car radio the AM dial is the number
of times in 1,000's per second and the FM is 1,000,000 per second.

Other devices do emit electrical signals that can be picked up by a
radio receiver. Not as easy today as in the past, since the
government has issued directives limiting the emitted power of
electrical devices, including radio receivers and computers. Also,
many if not all, hospitals have regulations forbidding the use of
cell phones because their emission could sometimes interfere with
other devices (I suspect ECG and EEG equipment would be
representative) within the building. MRI uses the radio emissions of
atoms stimulated by magnetic fields to map the body.

At one time at least, airlines banned the uses of radios, calculators,
computers on board because their emissions might interfere with the
planes' navigation devices.

A microwave oven is also a device depending on radio emission to
perform its task. Possible leakage of radio waves from these devices
has been a concern.

The possiblity of brain damage from cellular phones has been under
study for some time, so far with inconclusive evidence according to
the last news story I have seen on this subject. However, that has
not stopped a lawyer from filing a suit claiming such damage as I read
either today or yesterday.

I hope this is not too rambling to answer some of your questions.
Corrections and additions are welcome.